https://wiki.math.wisc.edu/api.php?action=feedcontributions&user=Nagreen&feedformat=atomUW-Math Wiki - User contributions [en]2022-12-06T08:27:12ZUser contributionsMediaWiki 1.35.6https://wiki.math.wisc.edu/index.php?title=Colloquia&diff=24099Colloquia2022-11-28T17:31:01Z<p>Nagreen: /* December 5, 2022, Monday at 4pm: Di Fang (Berkeley) */</p>
<hr />
<div>__NOTOC__<br />
<br />
In 2022-2023, our colloquia will be in-person talks in B239 unless otherwise stated. <br />
<br />
==September 9 , 2022, Friday at 4pm [https://math.ou.edu/~jing/ Jing Tao] (University of Oklahoma)==<br />
(host: Dymarz, Uyanik, WIMAW)<br />
<br />
'''On surface homeomorphisms'''<br />
<br />
In the 1970s, Thurston generalized the classification of self-maps of the torus to surfaces of higher genus, thus completing the work initiated by Nielsen. This is known as the Nielsen-Thurston Classification Theorem. Over the years, many alternative proofs have been obtained, using different aspects of surface theory. In this talk, I will overview the classical theory and sketch the ideas of a new proof, one that offers new insights into the hyperbolic geometry of surfaces. This is joint work with Camille Horbez.<br />
==September 23, 2022, Friday at 4pm [https://www.pabloshmerkin.org/ Pablo Shmerkin] (University of British Columbia) ==<br />
(host: Guo, Seeger)<br />
<br />
'''Incidences and line counting: from the discrete to the fractal setting'''<br />
<br />
How many lines are spanned by a set of planar points?. If the points are collinear, then the answer is clearly "one". If they are not collinear, however, several different answers exist when sets are finite and "how many" is measured by cardinality. I will discuss a bit of the history of this problem and present a recent extension to the continuum setting, obtained in collaboration with T. Orponen and H. Wang. No specialized background will be assumed.<br />
<br />
==September 30, 2022, Friday at 4pm [https://alejandraquintos.com/ Alejandra Quintos] (University of Wisconsin-Madison, Statistics) ==<br />
(host: Stovall)<br />
<br />
'''Dependent Stopping Times and an Application to Credit Risk Theory'''<br />
<br />
Stopping times are used in applications to model random arrivals. A standard assumption in many models is that the stopping times are conditionally independent, given an underlying filtration. This is a widely useful assumption, but there are circumstances where it seems to be unnecessarily strong. In the first part of the talk, we use a modified Cox construction, along with the bivariate exponential introduced by Marshall & Olkin (1967), to create a family of stopping times, which are not necessarily conditionally independent, allowing for a positive probability for them to be equal. We also present a series of results exploring the special properties of this construction.<br />
<br />
In the second part of the talk, we present an application of our model to Credit Risk. We characterize the probability of a market failure which is defined as the default of two or more globally systemically important banks (G-SIBs) in a small interval of time. The default probabilities of the G-SIBs are correlated through the possible existence of a market-wide stress event. We derive various theorems related to market failure probabilities, such as the probability of a catastrophic market failure, the impact of increasing the number of G-SIBs in an economy, and the impact of changing the initial conditions of the economy's state variables. We also show that if there are too many G-SIBs, a market failure is inevitable, i.e., the probability of a market failure tends to one as the number of G-SIBs tends to infinity.<br />
==October 7, 2022, Friday at 4pm [https://www.daniellitt.com/ Daniel Litt] (University of Toronto)==<br />
(host: Ananth Shankar)<br />
<br />
'''The search for special symmetries'''<br />
<br />
What are the canonical sets of symmetries of n-dimensional space? I'll describe the history of this question, going back to Schwarz, Fuchs, Painlevé, and others, and some new answers to it, obtained jointly with Aaron Landesman. While our results rely on low-dimensional topology, Hodge theory, and the Langlands program, and we'll get a peek into how these areas come into play, no knowledge of them will be assumed.<br />
<br />
==October 14, 2022, Friday at 4pm [https://math.sciences.ncsu.edu/people/asagema/ Andrew Sageman-Furnas] (North Carolina State)==<br />
(host: Mari-Beffa)<br />
<br />
'''Constructing isometric tori with the same curvatures'''<br />
<br />
Which data determine an immersed surface in Euclidean three-space up to rigid motion? A generic surface is locally determined by only an intrinsic metric and extrinsic mean curvature function. However, there are exceptions. These may arise in a family like the isometric family of vanishing mean curvature surfaces transforming a catenoid into a helicoid.<br />
<br />
For compact surfaces, Lawson and Tribuzy proved in 1981 that a metric and non-constant mean curvature function determine at most one immersion with genus zero, but at most two compact immersions (compact Bonnet pairs) for higher genus. In this talk, we discuss our recent construction of the first examples of compact Bonnet pairs. It uses a local classification by Kamberov, Pedit, and Pinkall in terms of isothermic surfaces. Moreover, we describe how a structure-preserving discrete theory for isothermic surfaces and Bonnet pairs led to this discovery.<br />
<br />
The smooth theory is joint work with Alexander Bobenko and Tim Hoffmann and the discrete theory is joint work with Tim Hoffmann and Max Wardetzky.<br />
<br />
== October 20, 2022, Thursday at 4pm, VV911 [https://tavarelab.cancerdynamics.columbia.edu/ Simon Tavaré] (Columbia University) ==<br />
(host: Kurtz, Roch)<br />
<br />
''Note the unusual time and room!''<br />
<br />
'''An introduction to counts-of-counts data'''<br />
<br />
Counts-of-counts data arise in many areas of biology and medicine, and have been studied by statisticians since the 1940s. One of the first examples, discussed by R. A. Fisher and collaborators in 1943 [1], concerns estimation of the number of unobserved species based on summary counts of the number of species observed once, twice, … in a sample of specimens. The data are summarized by the numbers ''C<sub>1</sub>, C<sub>2</sub>, …'' of species represented once, twice, … in a sample of size<br />
<br />
''N = C<sub>1</sub> + 2 C<sub>2</sub> + 3 C<sub>3</sub> + <sup>….</sup>'' containing ''S = C<sub>1</sub> + C<sub>2</sub> + <sup>…</sup>'' species; the vector ''C ='' ''(C<sub>1</sub>, C<sub>2</sub>, …)'' gives the counts-of-counts. Other examples include the frequencies of the distinct alleles in a human genetics sample, the counts of distinct variants of the SARS-CoV-2 S protein obtained from consensus sequencing experiments, counts of sizes of components in certain combinatorial structures [2], and counts of the numbers of SNVs arising in one cell, two cells, … in a cancer sequencing experiment.<br />
<br />
In this talk I will outline some of the stochastic models used to model the distribution of ''C,'' and some of the inferential issues that come from estimating the parameters of these models. I will touch on the celebrated Ewens Sampling Formula [3] and Fisher’s multiple sampling problem concerning the variance expected between values of ''S'' in samples taken from the same population [3]. Variants of birth-death-immigration processes can be used, for example when different variants grow at different rates. Some of these models are mechanistic in spirit, others more statistical. For example, a non-mechanistic model is useful for describing the arrival of covid sequences at a database. Sequences arrive one at a time, and are either a new variant, or a copy of a variant that has appeared before. The classical Yule process with immigration provides a starting point to model this process, as I will illustrate.<br />
<br />
''References''<br />
<br />
[1] Fisher RA, Corbet AS & Williams CB. J Animal Ecology, 12, 1943<br />
<br />
[2] Arratia R, Barbour AD & Tavaré S. ''Logarithmic Combinatorial Structures,'' EMS, 2002<br />
<br />
[3] Ewens WJ. Theoret Popul Biol, 3, 1972<br />
<br />
[4] Da Silva P, Jamshidpey A, McCullagh P & Tavaré S. Bernoulli Journal, in press, 2022 (online)<br />
<br />
==October 21, 2022, Friday at 4pm [https://web.ma.utexas.edu/users/ntran/ Ngoc Mai Tran] (Texas)==<br />
(host: Rodriguez)<br />
<br />
'''Forecast science, learn hidden networks and settle economics conjectures with combinatorics, geometry and probability.''' <br />
<br />
In many problems, one observes noisy data coming from a hidden or complex combinatorial structure. My research aims to understand and exploit such structures to arrive at an efficient and optimal solution. I will showcase a few successes, achieved with different tools, from different different fields: networks forecasting, hydrology, and auction theory. Then I will outline some open questions in each field. <br />
<br />
==October 28, 2022, Friday at 4pm [https://people.math.wisc.edu/~qinli/ Qin Li] (UW)==<br />
'''Multiscale inverse problem, from Schroedinger to Newton to Boltzmann'''<br />
<br />
Inverse problems are ubiquitous. We probe the media with sources and measure the outputs, to infer the media information. At the scale of quantum, classical, statistical and fluid, we face inverse Schroedinger, inverse Newton’s second law, inverse Boltzmann problem, and inverse diffusion respectively. The universe, however, expects a universal mathematical description, as Hilbert proposed in 1900. In this talk, we discuss the connection between these problems. We will give arguments for justifying that these are the same problem merely represented at different scales. It is a light-hearted talk, and I will mostly focus on the story instead of the derivation. PDE background is appreciated but not necessary.<br />
<br />
== November 7, 2022, Monday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures<br />
<br />
(host: Yang).<br />
<br />
'''Private AI: Machine Learning on Encrypted Data'''<br />
<br />
As the world adopts Artificial Intelligence, the privacy risks are many. AI can improve our lives, but may leak our private data. Private AI is based on Homomorphic Encryption (HE), a new encryption paradigm which allows the cloud to operate on private data in encrypted form, without ever decrypting it, enabling private training and private prediction. Our 2016 ICML CryptoNets paper showed for the first time that it was possible to evaluate neural nets on homomorphically encrypted data, and opened new research directions combining machine learning and cryptography. The security of Homomorphic Encryption is based on hard problems in mathematics involving lattices, recently standardized by NIST for post-quantum cryptography. This talk will explain Homomorphic Encryption, Private AI, and explain HE in action.<br />
<br />
== November 8, 2022, Tuesday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures in VV911. ''Note: unusual room.''<br />
<br />
(host: Yang).<br />
<br />
'''Artificial Intelligence & Cryptography: Privacy and Security in the AI era'''<br />
<br />
How is Artificial Intelligence changing your life and the world? How do you expect your data to be kept secure and private in the future? Artificial intelligence (AI) refers to the science of utilizing data to formulate mathematical models that predict outcomes with high assurance. Such predictions can be used to make decisions automatically or give recommendations with high confidence. Cryptography is the science of protecting the privacy and security of data. This talk will explain the dynamic relationship between cryptography and AI and how AI can be used to attack post-quantum cryptosystems.<br />
<br />
The first talk is based on my 2019 ICIAM Plenary Lecture and the second one is based on my 2022 SIAM Block Prize Lecture.<br />
<br />
== November 11, 2022, Friday at 4pm [http://users.cms.caltech.edu/~jtropp/ Joel Tropp] (Caltech)==<br />
This is the Annual LAA lecture. See [https://math.wisc.edu/laa-lecture/ this] for its history.<br />
<br />
(host: Qin, Jordan)<br />
<br />
'''Rocket-propelled Cholesky: Addressing the challenges of large-scale kernel computations'''<br />
<br />
Kernel methods are used for prediction and clustering in many data science and scientific computing applications, but applying kernel methods to a large number of data points N is expensive due to the high cost of manipulating the N x N kernel matrix. A basic approach for speeding up kernel computations is low-rank approximation, in which we replace the kernel matrix A with a factorized approximation that can be stored and manipulated more cheaply. When the kernel matrix A has rapidly decaying eigenvalues, mathematical existence proofs guarantee that A can be accurately approximated using a constant number of columns (without ever looking at the full matrix). Nevertheless, for a long time designing a practical and provably justified algorithm to select the appropriate columns proved challenging.<br />
<br />
Recently, we introduced RPCholesky ("randomly pivoted" or "rocket-propelled" Cholesky), a natural algorithm for approximating an N x N positive semidefinite matrix using k adaptively sampled columns. RPCholesky can be implemented with just a few lines of code; it requires only (k+1)N entry evaluations and O(k^2 N) additional arithmetic operations. In experiments, RPCholesky matches or improves on the performance of alternative algorithms for low-rank psd approximation. Moreover, RPCholesky provably achieves near-optimal approximation guarantees. The simplicity, effectiveness, and robustness of this algorithm strongly support its use for large-scale kernel computations.<br />
<br />
Joint work with Yifan Chen, Ethan Epperly, and Rob Webber. Available at arXiv:2207.06503.<br />
<br />
==November 18, 2022, Friday at 4pm [http://homepages.math.uic.edu/~freitag/index.html Jim Freitag] (U of Illinois-Chicago) Zoom link: https://go.wisc.edu/jimfreitag<nowiki/>==<br />
'''Now available:''' [https://people.math.wisc.edu/logic/talks/221118-Freitag.mp4 Recording] and [https://people.math.wisc.edu/logic/talks/221118-Freitag.pdf Slides]<br />
<br />
(hosts: Lempp, Andrews)<br />
<br />
'''When any three solutions are independent'''<br />
<br />
In this talk, we'll talk about a surprising recent result about the algebraic relations between solutions of a differential equation. The result has applications to functional transcendence, diophantine geometry, and compact complex manifolds.<br />
<br />
==November 21, 2022, <span style="color: red;">Monday</span> at 4pm [https://math.mit.edu/directory/profile.html?pid=1698 Andrei Negut] (MIT) Zoom link: [https://go.wisc.edu/andreinegut https://go.wisc.edu/andreinegut]==<br />
Hiring talk.<br />
<br />
(hosts: Arinkin, Caldararu)<br />
<br />
'''From gauge theory to geometric representation theory and back'''<br />
<br />
We start from the celebrated construction (due to Grojnowski and Nakajima) of a Heisenberg algebra action on the cohomology groups of Hilbert schemes of points on surfaces<br />
<br />
# replacing Hilbert schemes with moduli spaces of higher rank sheaves yields a computation of Nekrasov partition functions in 5d supersymmetric gauge theory, and a proof of the deformed Alday-Gaiotto-Tachikawa conjecture.<br />
# replacing cohomology by Chow groups gives a proof of the Beauville conjecture in the hyperkahler geometry of Hilbert schemes of points on K3 surfaces (with Maulik)<br />
# working with derived categories allows us to construct a detailed framework realizing categorical knot invariants in terms of the geometry of Hilbert schemes of points on the affine plane (with Gorsky and Rasmussen)<br />
<br />
==December 2, 2022, Friday at 4pm: Promit Ghosal (MIT)==<br />
'''Fractal Geometry of the KPZ equation'''<br />
<br />
The Kardar-Parisi-Zhang (KPZ) equation is a fundamental stochastic PDE related to many important models like random growth processes, Burgers turbulence, interacting particles system, random polymers etc. In this talk, we focus on how the tall peaks and deep valleys of the KPZ height function grow as time increases. In particular, we will ask what is the appropriate scaling of the peaks and valleys of the (1+1)-d KPZ equation and whether they converge to any limit under those scaling. These questions will be answered via the law of iterated logarithms and fractal dimensions of the level sets. The talk will be based on joint works with Sayan Das and Jaeyun Yi. If time permits, I will also mention an interesting story about the (2+1)-d and (3+1)-d case (work in progress with Jaeyun Yi).<br />
<br />
== December 5, 2022, Monday at 4pm: Di Fang (Berkeley) ==<br />
(reserved by HC. contact: Stechmann)<br />
<br />
== December 7, 2022, Wednesday at 4pm: Benjamin Eichinger (Vienna University of Technology) ==<br />
(reserved by HC. contact: Stechmann)<br />
<br />
==December 9, 2022, Friday at 4pm: Dallas Albritton (Princeton)==<br />
(reserved by HC. contact: Stechmann)<br />
<br />
== December 12, 2022, Monday at 4pm: Laurel Ohm (Princeton) ==<br />
(reserved by HC. contact: Stechmann)<br />
<br />
== Future Colloquia ==<br />
<br />
[[Colloquia/Fall2022|Fall 2022]]<br />
<br />
[[Colloquia/Spring2023|Spring 2023]]<br />
<br />
== Past Colloquia ==<br />
[[Spring 2022 Colloquiums|Spring 2022]]<br />
<br />
[[Colloquia/Fall2021|Fall 2021]]<br />
<br />
[[Colloquia/Spring2021|Spring 2021]]<br />
<br />
[[Colloquia/Fall2020|Fall 2020]]<br />
<br />
[[Colloquia/Spring2020|Spring 2020]]<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]<br />
<br />
[[WIMAW]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Colloquia&diff=24098Colloquia2022-11-28T17:29:31Z<p>Nagreen: /* December 2, 2022, Friday at 4pm: Promit Ghosal (MIT) */</p>
<hr />
<div>__NOTOC__<br />
<br />
In 2022-2023, our colloquia will be in-person talks in B239 unless otherwise stated. <br />
<br />
==September 9 , 2022, Friday at 4pm [https://math.ou.edu/~jing/ Jing Tao] (University of Oklahoma)==<br />
(host: Dymarz, Uyanik, WIMAW)<br />
<br />
'''On surface homeomorphisms'''<br />
<br />
In the 1970s, Thurston generalized the classification of self-maps of the torus to surfaces of higher genus, thus completing the work initiated by Nielsen. This is known as the Nielsen-Thurston Classification Theorem. Over the years, many alternative proofs have been obtained, using different aspects of surface theory. In this talk, I will overview the classical theory and sketch the ideas of a new proof, one that offers new insights into the hyperbolic geometry of surfaces. This is joint work with Camille Horbez.<br />
==September 23, 2022, Friday at 4pm [https://www.pabloshmerkin.org/ Pablo Shmerkin] (University of British Columbia) ==<br />
(host: Guo, Seeger)<br />
<br />
'''Incidences and line counting: from the discrete to the fractal setting'''<br />
<br />
How many lines are spanned by a set of planar points?. If the points are collinear, then the answer is clearly "one". If they are not collinear, however, several different answers exist when sets are finite and "how many" is measured by cardinality. I will discuss a bit of the history of this problem and present a recent extension to the continuum setting, obtained in collaboration with T. Orponen and H. Wang. No specialized background will be assumed.<br />
<br />
==September 30, 2022, Friday at 4pm [https://alejandraquintos.com/ Alejandra Quintos] (University of Wisconsin-Madison, Statistics) ==<br />
(host: Stovall)<br />
<br />
'''Dependent Stopping Times and an Application to Credit Risk Theory'''<br />
<br />
Stopping times are used in applications to model random arrivals. A standard assumption in many models is that the stopping times are conditionally independent, given an underlying filtration. This is a widely useful assumption, but there are circumstances where it seems to be unnecessarily strong. In the first part of the talk, we use a modified Cox construction, along with the bivariate exponential introduced by Marshall & Olkin (1967), to create a family of stopping times, which are not necessarily conditionally independent, allowing for a positive probability for them to be equal. We also present a series of results exploring the special properties of this construction.<br />
<br />
In the second part of the talk, we present an application of our model to Credit Risk. We characterize the probability of a market failure which is defined as the default of two or more globally systemically important banks (G-SIBs) in a small interval of time. The default probabilities of the G-SIBs are correlated through the possible existence of a market-wide stress event. We derive various theorems related to market failure probabilities, such as the probability of a catastrophic market failure, the impact of increasing the number of G-SIBs in an economy, and the impact of changing the initial conditions of the economy's state variables. We also show that if there are too many G-SIBs, a market failure is inevitable, i.e., the probability of a market failure tends to one as the number of G-SIBs tends to infinity.<br />
==October 7, 2022, Friday at 4pm [https://www.daniellitt.com/ Daniel Litt] (University of Toronto)==<br />
(host: Ananth Shankar)<br />
<br />
'''The search for special symmetries'''<br />
<br />
What are the canonical sets of symmetries of n-dimensional space? I'll describe the history of this question, going back to Schwarz, Fuchs, Painlevé, and others, and some new answers to it, obtained jointly with Aaron Landesman. While our results rely on low-dimensional topology, Hodge theory, and the Langlands program, and we'll get a peek into how these areas come into play, no knowledge of them will be assumed.<br />
<br />
==October 14, 2022, Friday at 4pm [https://math.sciences.ncsu.edu/people/asagema/ Andrew Sageman-Furnas] (North Carolina State)==<br />
(host: Mari-Beffa)<br />
<br />
'''Constructing isometric tori with the same curvatures'''<br />
<br />
Which data determine an immersed surface in Euclidean three-space up to rigid motion? A generic surface is locally determined by only an intrinsic metric and extrinsic mean curvature function. However, there are exceptions. These may arise in a family like the isometric family of vanishing mean curvature surfaces transforming a catenoid into a helicoid.<br />
<br />
For compact surfaces, Lawson and Tribuzy proved in 1981 that a metric and non-constant mean curvature function determine at most one immersion with genus zero, but at most two compact immersions (compact Bonnet pairs) for higher genus. In this talk, we discuss our recent construction of the first examples of compact Bonnet pairs. It uses a local classification by Kamberov, Pedit, and Pinkall in terms of isothermic surfaces. Moreover, we describe how a structure-preserving discrete theory for isothermic surfaces and Bonnet pairs led to this discovery.<br />
<br />
The smooth theory is joint work with Alexander Bobenko and Tim Hoffmann and the discrete theory is joint work with Tim Hoffmann and Max Wardetzky.<br />
<br />
== October 20, 2022, Thursday at 4pm, VV911 [https://tavarelab.cancerdynamics.columbia.edu/ Simon Tavaré] (Columbia University) ==<br />
(host: Kurtz, Roch)<br />
<br />
''Note the unusual time and room!''<br />
<br />
'''An introduction to counts-of-counts data'''<br />
<br />
Counts-of-counts data arise in many areas of biology and medicine, and have been studied by statisticians since the 1940s. One of the first examples, discussed by R. A. Fisher and collaborators in 1943 [1], concerns estimation of the number of unobserved species based on summary counts of the number of species observed once, twice, … in a sample of specimens. The data are summarized by the numbers ''C<sub>1</sub>, C<sub>2</sub>, …'' of species represented once, twice, … in a sample of size<br />
<br />
''N = C<sub>1</sub> + 2 C<sub>2</sub> + 3 C<sub>3</sub> + <sup>….</sup>'' containing ''S = C<sub>1</sub> + C<sub>2</sub> + <sup>…</sup>'' species; the vector ''C ='' ''(C<sub>1</sub>, C<sub>2</sub>, …)'' gives the counts-of-counts. Other examples include the frequencies of the distinct alleles in a human genetics sample, the counts of distinct variants of the SARS-CoV-2 S protein obtained from consensus sequencing experiments, counts of sizes of components in certain combinatorial structures [2], and counts of the numbers of SNVs arising in one cell, two cells, … in a cancer sequencing experiment.<br />
<br />
In this talk I will outline some of the stochastic models used to model the distribution of ''C,'' and some of the inferential issues that come from estimating the parameters of these models. I will touch on the celebrated Ewens Sampling Formula [3] and Fisher’s multiple sampling problem concerning the variance expected between values of ''S'' in samples taken from the same population [3]. Variants of birth-death-immigration processes can be used, for example when different variants grow at different rates. Some of these models are mechanistic in spirit, others more statistical. For example, a non-mechanistic model is useful for describing the arrival of covid sequences at a database. Sequences arrive one at a time, and are either a new variant, or a copy of a variant that has appeared before. The classical Yule process with immigration provides a starting point to model this process, as I will illustrate.<br />
<br />
''References''<br />
<br />
[1] Fisher RA, Corbet AS & Williams CB. J Animal Ecology, 12, 1943<br />
<br />
[2] Arratia R, Barbour AD & Tavaré S. ''Logarithmic Combinatorial Structures,'' EMS, 2002<br />
<br />
[3] Ewens WJ. Theoret Popul Biol, 3, 1972<br />
<br />
[4] Da Silva P, Jamshidpey A, McCullagh P & Tavaré S. Bernoulli Journal, in press, 2022 (online)<br />
<br />
==October 21, 2022, Friday at 4pm [https://web.ma.utexas.edu/users/ntran/ Ngoc Mai Tran] (Texas)==<br />
(host: Rodriguez)<br />
<br />
'''Forecast science, learn hidden networks and settle economics conjectures with combinatorics, geometry and probability.''' <br />
<br />
In many problems, one observes noisy data coming from a hidden or complex combinatorial structure. My research aims to understand and exploit such structures to arrive at an efficient and optimal solution. I will showcase a few successes, achieved with different tools, from different different fields: networks forecasting, hydrology, and auction theory. Then I will outline some open questions in each field. <br />
<br />
==October 28, 2022, Friday at 4pm [https://people.math.wisc.edu/~qinli/ Qin Li] (UW)==<br />
'''Multiscale inverse problem, from Schroedinger to Newton to Boltzmann'''<br />
<br />
Inverse problems are ubiquitous. We probe the media with sources and measure the outputs, to infer the media information. At the scale of quantum, classical, statistical and fluid, we face inverse Schroedinger, inverse Newton’s second law, inverse Boltzmann problem, and inverse diffusion respectively. The universe, however, expects a universal mathematical description, as Hilbert proposed in 1900. In this talk, we discuss the connection between these problems. We will give arguments for justifying that these are the same problem merely represented at different scales. It is a light-hearted talk, and I will mostly focus on the story instead of the derivation. PDE background is appreciated but not necessary.<br />
<br />
== November 7, 2022, Monday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures<br />
<br />
(host: Yang).<br />
<br />
'''Private AI: Machine Learning on Encrypted Data'''<br />
<br />
As the world adopts Artificial Intelligence, the privacy risks are many. AI can improve our lives, but may leak our private data. Private AI is based on Homomorphic Encryption (HE), a new encryption paradigm which allows the cloud to operate on private data in encrypted form, without ever decrypting it, enabling private training and private prediction. Our 2016 ICML CryptoNets paper showed for the first time that it was possible to evaluate neural nets on homomorphically encrypted data, and opened new research directions combining machine learning and cryptography. The security of Homomorphic Encryption is based on hard problems in mathematics involving lattices, recently standardized by NIST for post-quantum cryptography. This talk will explain Homomorphic Encryption, Private AI, and explain HE in action.<br />
<br />
== November 8, 2022, Tuesday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures in VV911. ''Note: unusual room.''<br />
<br />
(host: Yang).<br />
<br />
'''Artificial Intelligence & Cryptography: Privacy and Security in the AI era'''<br />
<br />
How is Artificial Intelligence changing your life and the world? How do you expect your data to be kept secure and private in the future? Artificial intelligence (AI) refers to the science of utilizing data to formulate mathematical models that predict outcomes with high assurance. Such predictions can be used to make decisions automatically or give recommendations with high confidence. Cryptography is the science of protecting the privacy and security of data. This talk will explain the dynamic relationship between cryptography and AI and how AI can be used to attack post-quantum cryptosystems.<br />
<br />
The first talk is based on my 2019 ICIAM Plenary Lecture and the second one is based on my 2022 SIAM Block Prize Lecture.<br />
<br />
== November 11, 2022, Friday at 4pm [http://users.cms.caltech.edu/~jtropp/ Joel Tropp] (Caltech)==<br />
This is the Annual LAA lecture. See [https://math.wisc.edu/laa-lecture/ this] for its history.<br />
<br />
(host: Qin, Jordan)<br />
<br />
'''Rocket-propelled Cholesky: Addressing the challenges of large-scale kernel computations'''<br />
<br />
Kernel methods are used for prediction and clustering in many data science and scientific computing applications, but applying kernel methods to a large number of data points N is expensive due to the high cost of manipulating the N x N kernel matrix. A basic approach for speeding up kernel computations is low-rank approximation, in which we replace the kernel matrix A with a factorized approximation that can be stored and manipulated more cheaply. When the kernel matrix A has rapidly decaying eigenvalues, mathematical existence proofs guarantee that A can be accurately approximated using a constant number of columns (without ever looking at the full matrix). Nevertheless, for a long time designing a practical and provably justified algorithm to select the appropriate columns proved challenging.<br />
<br />
Recently, we introduced RPCholesky ("randomly pivoted" or "rocket-propelled" Cholesky), a natural algorithm for approximating an N x N positive semidefinite matrix using k adaptively sampled columns. RPCholesky can be implemented with just a few lines of code; it requires only (k+1)N entry evaluations and O(k^2 N) additional arithmetic operations. In experiments, RPCholesky matches or improves on the performance of alternative algorithms for low-rank psd approximation. Moreover, RPCholesky provably achieves near-optimal approximation guarantees. The simplicity, effectiveness, and robustness of this algorithm strongly support its use for large-scale kernel computations.<br />
<br />
Joint work with Yifan Chen, Ethan Epperly, and Rob Webber. Available at arXiv:2207.06503.<br />
<br />
==November 18, 2022, Friday at 4pm [http://homepages.math.uic.edu/~freitag/index.html Jim Freitag] (U of Illinois-Chicago) Zoom link: https://go.wisc.edu/jimfreitag<nowiki/>==<br />
'''Now available:''' [https://people.math.wisc.edu/logic/talks/221118-Freitag.mp4 Recording] and [https://people.math.wisc.edu/logic/talks/221118-Freitag.pdf Slides]<br />
<br />
(hosts: Lempp, Andrews)<br />
<br />
'''When any three solutions are independent'''<br />
<br />
In this talk, we'll talk about a surprising recent result about the algebraic relations between solutions of a differential equation. The result has applications to functional transcendence, diophantine geometry, and compact complex manifolds.<br />
<br />
==November 21, 2022, <span style="color: red;">Monday</span> at 4pm [https://math.mit.edu/directory/profile.html?pid=1698 Andrei Negut] (MIT) Zoom link: [https://go.wisc.edu/andreinegut https://go.wisc.edu/andreinegut]==<br />
Hiring talk.<br />
<br />
(hosts: Arinkin, Caldararu)<br />
<br />
'''From gauge theory to geometric representation theory and back'''<br />
<br />
We start from the celebrated construction (due to Grojnowski and Nakajima) of a Heisenberg algebra action on the cohomology groups of Hilbert schemes of points on surfaces<br />
<br />
# replacing Hilbert schemes with moduli spaces of higher rank sheaves yields a computation of Nekrasov partition functions in 5d supersymmetric gauge theory, and a proof of the deformed Alday-Gaiotto-Tachikawa conjecture.<br />
# replacing cohomology by Chow groups gives a proof of the Beauville conjecture in the hyperkahler geometry of Hilbert schemes of points on K3 surfaces (with Maulik)<br />
# working with derived categories allows us to construct a detailed framework realizing categorical knot invariants in terms of the geometry of Hilbert schemes of points on the affine plane (with Gorsky and Rasmussen)<br />
<br />
==December 2, 2022, Friday at 4pm: Promit Ghosal (MIT)==<br />
'''Fractal Geometry of the KPZ equation'''<br />
<br />
The Kardar-Parisi-Zhang (KPZ) equation is a fundamental stochastic PDE related to many important models like random growth processes, Burgers turbulence, interacting particles system, random polymers etc. In this talk, we focus on how the tall peaks and deep valleys of the KPZ height function grow as time increases. In particular, we will ask what is the appropriate scaling of the peaks and valleys of the (1+1)-d KPZ equation and whether they converge to any limit under those scaling. These questions will be answered via the law of iterated logarithms and fractal dimensions of the level sets. The talk will be based on joint works with Sayan Das and Jaeyun Yi. If time permits, I will also mention an interesting story about the (2+1)-d and (3+1)-d case (work in progress with Jaeyun Yi).<br />
<br />
== December 5, 2022, Monday at 4pm: Di Fang (Berkeley) ==<br />
(reserved by HC. contact: Stechmann)<br />
<br />
==December 9, 2022, Friday at 4pm: Dallas Albritton (Princeton)==<br />
(reserved by HC. contact: Stechmann)<br />
<br />
== December 12, 2022, Monday at 4pm: Laurel Ohm (Princeton) ==<br />
(reserved by HC. contact: Stechmann)<br />
<br />
== Future Colloquia ==<br />
<br />
[[Colloquia/Fall2022|Fall 2022]]<br />
<br />
[[Colloquia/Spring2023|Spring 2023]]<br />
<br />
== Past Colloquia ==<br />
[[Spring 2022 Colloquiums|Spring 2022]]<br />
<br />
[[Colloquia/Fall2021|Fall 2021]]<br />
<br />
[[Colloquia/Spring2021|Spring 2021]]<br />
<br />
[[Colloquia/Fall2020|Fall 2020]]<br />
<br />
[[Colloquia/Spring2020|Spring 2020]]<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]<br />
<br />
[[WIMAW]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Colloquia&diff=24097Colloquia2022-11-28T17:28:38Z<p>Nagreen: /* December 9, 2022, Friday at 4pm: Dallas Albritton (Princeton) */</p>
<hr />
<div>__NOTOC__<br />
<br />
In 2022-2023, our colloquia will be in-person talks in B239 unless otherwise stated. <br />
<br />
==September 9 , 2022, Friday at 4pm [https://math.ou.edu/~jing/ Jing Tao] (University of Oklahoma)==<br />
(host: Dymarz, Uyanik, WIMAW)<br />
<br />
'''On surface homeomorphisms'''<br />
<br />
In the 1970s, Thurston generalized the classification of self-maps of the torus to surfaces of higher genus, thus completing the work initiated by Nielsen. This is known as the Nielsen-Thurston Classification Theorem. Over the years, many alternative proofs have been obtained, using different aspects of surface theory. In this talk, I will overview the classical theory and sketch the ideas of a new proof, one that offers new insights into the hyperbolic geometry of surfaces. This is joint work with Camille Horbez.<br />
==September 23, 2022, Friday at 4pm [https://www.pabloshmerkin.org/ Pablo Shmerkin] (University of British Columbia) ==<br />
(host: Guo, Seeger)<br />
<br />
'''Incidences and line counting: from the discrete to the fractal setting'''<br />
<br />
How many lines are spanned by a set of planar points?. If the points are collinear, then the answer is clearly "one". If they are not collinear, however, several different answers exist when sets are finite and "how many" is measured by cardinality. I will discuss a bit of the history of this problem and present a recent extension to the continuum setting, obtained in collaboration with T. Orponen and H. Wang. No specialized background will be assumed.<br />
<br />
==September 30, 2022, Friday at 4pm [https://alejandraquintos.com/ Alejandra Quintos] (University of Wisconsin-Madison, Statistics) ==<br />
(host: Stovall)<br />
<br />
'''Dependent Stopping Times and an Application to Credit Risk Theory'''<br />
<br />
Stopping times are used in applications to model random arrivals. A standard assumption in many models is that the stopping times are conditionally independent, given an underlying filtration. This is a widely useful assumption, but there are circumstances where it seems to be unnecessarily strong. In the first part of the talk, we use a modified Cox construction, along with the bivariate exponential introduced by Marshall & Olkin (1967), to create a family of stopping times, which are not necessarily conditionally independent, allowing for a positive probability for them to be equal. We also present a series of results exploring the special properties of this construction.<br />
<br />
In the second part of the talk, we present an application of our model to Credit Risk. We characterize the probability of a market failure which is defined as the default of two or more globally systemically important banks (G-SIBs) in a small interval of time. The default probabilities of the G-SIBs are correlated through the possible existence of a market-wide stress event. We derive various theorems related to market failure probabilities, such as the probability of a catastrophic market failure, the impact of increasing the number of G-SIBs in an economy, and the impact of changing the initial conditions of the economy's state variables. We also show that if there are too many G-SIBs, a market failure is inevitable, i.e., the probability of a market failure tends to one as the number of G-SIBs tends to infinity.<br />
==October 7, 2022, Friday at 4pm [https://www.daniellitt.com/ Daniel Litt] (University of Toronto)==<br />
(host: Ananth Shankar)<br />
<br />
'''The search for special symmetries'''<br />
<br />
What are the canonical sets of symmetries of n-dimensional space? I'll describe the history of this question, going back to Schwarz, Fuchs, Painlevé, and others, and some new answers to it, obtained jointly with Aaron Landesman. While our results rely on low-dimensional topology, Hodge theory, and the Langlands program, and we'll get a peek into how these areas come into play, no knowledge of them will be assumed.<br />
<br />
==October 14, 2022, Friday at 4pm [https://math.sciences.ncsu.edu/people/asagema/ Andrew Sageman-Furnas] (North Carolina State)==<br />
(host: Mari-Beffa)<br />
<br />
'''Constructing isometric tori with the same curvatures'''<br />
<br />
Which data determine an immersed surface in Euclidean three-space up to rigid motion? A generic surface is locally determined by only an intrinsic metric and extrinsic mean curvature function. However, there are exceptions. These may arise in a family like the isometric family of vanishing mean curvature surfaces transforming a catenoid into a helicoid.<br />
<br />
For compact surfaces, Lawson and Tribuzy proved in 1981 that a metric and non-constant mean curvature function determine at most one immersion with genus zero, but at most two compact immersions (compact Bonnet pairs) for higher genus. In this talk, we discuss our recent construction of the first examples of compact Bonnet pairs. It uses a local classification by Kamberov, Pedit, and Pinkall in terms of isothermic surfaces. Moreover, we describe how a structure-preserving discrete theory for isothermic surfaces and Bonnet pairs led to this discovery.<br />
<br />
The smooth theory is joint work with Alexander Bobenko and Tim Hoffmann and the discrete theory is joint work with Tim Hoffmann and Max Wardetzky.<br />
<br />
== October 20, 2022, Thursday at 4pm, VV911 [https://tavarelab.cancerdynamics.columbia.edu/ Simon Tavaré] (Columbia University) ==<br />
(host: Kurtz, Roch)<br />
<br />
''Note the unusual time and room!''<br />
<br />
'''An introduction to counts-of-counts data'''<br />
<br />
Counts-of-counts data arise in many areas of biology and medicine, and have been studied by statisticians since the 1940s. One of the first examples, discussed by R. A. Fisher and collaborators in 1943 [1], concerns estimation of the number of unobserved species based on summary counts of the number of species observed once, twice, … in a sample of specimens. The data are summarized by the numbers ''C<sub>1</sub>, C<sub>2</sub>, …'' of species represented once, twice, … in a sample of size<br />
<br />
''N = C<sub>1</sub> + 2 C<sub>2</sub> + 3 C<sub>3</sub> + <sup>….</sup>'' containing ''S = C<sub>1</sub> + C<sub>2</sub> + <sup>…</sup>'' species; the vector ''C ='' ''(C<sub>1</sub>, C<sub>2</sub>, …)'' gives the counts-of-counts. Other examples include the frequencies of the distinct alleles in a human genetics sample, the counts of distinct variants of the SARS-CoV-2 S protein obtained from consensus sequencing experiments, counts of sizes of components in certain combinatorial structures [2], and counts of the numbers of SNVs arising in one cell, two cells, … in a cancer sequencing experiment.<br />
<br />
In this talk I will outline some of the stochastic models used to model the distribution of ''C,'' and some of the inferential issues that come from estimating the parameters of these models. I will touch on the celebrated Ewens Sampling Formula [3] and Fisher’s multiple sampling problem concerning the variance expected between values of ''S'' in samples taken from the same population [3]. Variants of birth-death-immigration processes can be used, for example when different variants grow at different rates. Some of these models are mechanistic in spirit, others more statistical. For example, a non-mechanistic model is useful for describing the arrival of covid sequences at a database. Sequences arrive one at a time, and are either a new variant, or a copy of a variant that has appeared before. The classical Yule process with immigration provides a starting point to model this process, as I will illustrate.<br />
<br />
''References''<br />
<br />
[1] Fisher RA, Corbet AS & Williams CB. J Animal Ecology, 12, 1943<br />
<br />
[2] Arratia R, Barbour AD & Tavaré S. ''Logarithmic Combinatorial Structures,'' EMS, 2002<br />
<br />
[3] Ewens WJ. Theoret Popul Biol, 3, 1972<br />
<br />
[4] Da Silva P, Jamshidpey A, McCullagh P & Tavaré S. Bernoulli Journal, in press, 2022 (online)<br />
<br />
==October 21, 2022, Friday at 4pm [https://web.ma.utexas.edu/users/ntran/ Ngoc Mai Tran] (Texas)==<br />
(host: Rodriguez)<br />
<br />
'''Forecast science, learn hidden networks and settle economics conjectures with combinatorics, geometry and probability.''' <br />
<br />
In many problems, one observes noisy data coming from a hidden or complex combinatorial structure. My research aims to understand and exploit such structures to arrive at an efficient and optimal solution. I will showcase a few successes, achieved with different tools, from different different fields: networks forecasting, hydrology, and auction theory. Then I will outline some open questions in each field. <br />
<br />
==October 28, 2022, Friday at 4pm [https://people.math.wisc.edu/~qinli/ Qin Li] (UW)==<br />
'''Multiscale inverse problem, from Schroedinger to Newton to Boltzmann'''<br />
<br />
Inverse problems are ubiquitous. We probe the media with sources and measure the outputs, to infer the media information. At the scale of quantum, classical, statistical and fluid, we face inverse Schroedinger, inverse Newton’s second law, inverse Boltzmann problem, and inverse diffusion respectively. The universe, however, expects a universal mathematical description, as Hilbert proposed in 1900. In this talk, we discuss the connection between these problems. We will give arguments for justifying that these are the same problem merely represented at different scales. It is a light-hearted talk, and I will mostly focus on the story instead of the derivation. PDE background is appreciated but not necessary.<br />
<br />
== November 7, 2022, Monday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures<br />
<br />
(host: Yang).<br />
<br />
'''Private AI: Machine Learning on Encrypted Data'''<br />
<br />
As the world adopts Artificial Intelligence, the privacy risks are many. AI can improve our lives, but may leak our private data. Private AI is based on Homomorphic Encryption (HE), a new encryption paradigm which allows the cloud to operate on private data in encrypted form, without ever decrypting it, enabling private training and private prediction. Our 2016 ICML CryptoNets paper showed for the first time that it was possible to evaluate neural nets on homomorphically encrypted data, and opened new research directions combining machine learning and cryptography. The security of Homomorphic Encryption is based on hard problems in mathematics involving lattices, recently standardized by NIST for post-quantum cryptography. This talk will explain Homomorphic Encryption, Private AI, and explain HE in action.<br />
<br />
== November 8, 2022, Tuesday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures in VV911. ''Note: unusual room.''<br />
<br />
(host: Yang).<br />
<br />
'''Artificial Intelligence & Cryptography: Privacy and Security in the AI era'''<br />
<br />
How is Artificial Intelligence changing your life and the world? How do you expect your data to be kept secure and private in the future? Artificial intelligence (AI) refers to the science of utilizing data to formulate mathematical models that predict outcomes with high assurance. Such predictions can be used to make decisions automatically or give recommendations with high confidence. Cryptography is the science of protecting the privacy and security of data. This talk will explain the dynamic relationship between cryptography and AI and how AI can be used to attack post-quantum cryptosystems.<br />
<br />
The first talk is based on my 2019 ICIAM Plenary Lecture and the second one is based on my 2022 SIAM Block Prize Lecture.<br />
<br />
== November 11, 2022, Friday at 4pm [http://users.cms.caltech.edu/~jtropp/ Joel Tropp] (Caltech)==<br />
This is the Annual LAA lecture. See [https://math.wisc.edu/laa-lecture/ this] for its history.<br />
<br />
(host: Qin, Jordan)<br />
<br />
'''Rocket-propelled Cholesky: Addressing the challenges of large-scale kernel computations'''<br />
<br />
Kernel methods are used for prediction and clustering in many data science and scientific computing applications, but applying kernel methods to a large number of data points N is expensive due to the high cost of manipulating the N x N kernel matrix. A basic approach for speeding up kernel computations is low-rank approximation, in which we replace the kernel matrix A with a factorized approximation that can be stored and manipulated more cheaply. When the kernel matrix A has rapidly decaying eigenvalues, mathematical existence proofs guarantee that A can be accurately approximated using a constant number of columns (without ever looking at the full matrix). Nevertheless, for a long time designing a practical and provably justified algorithm to select the appropriate columns proved challenging.<br />
<br />
Recently, we introduced RPCholesky ("randomly pivoted" or "rocket-propelled" Cholesky), a natural algorithm for approximating an N x N positive semidefinite matrix using k adaptively sampled columns. RPCholesky can be implemented with just a few lines of code; it requires only (k+1)N entry evaluations and O(k^2 N) additional arithmetic operations. In experiments, RPCholesky matches or improves on the performance of alternative algorithms for low-rank psd approximation. Moreover, RPCholesky provably achieves near-optimal approximation guarantees. The simplicity, effectiveness, and robustness of this algorithm strongly support its use for large-scale kernel computations.<br />
<br />
Joint work with Yifan Chen, Ethan Epperly, and Rob Webber. Available at arXiv:2207.06503.<br />
<br />
==November 18, 2022, Friday at 4pm [http://homepages.math.uic.edu/~freitag/index.html Jim Freitag] (U of Illinois-Chicago) Zoom link: https://go.wisc.edu/jimfreitag<nowiki/>==<br />
'''Now available:''' [https://people.math.wisc.edu/logic/talks/221118-Freitag.mp4 Recording] and [https://people.math.wisc.edu/logic/talks/221118-Freitag.pdf Slides]<br />
<br />
(hosts: Lempp, Andrews)<br />
<br />
'''When any three solutions are independent'''<br />
<br />
In this talk, we'll talk about a surprising recent result about the algebraic relations between solutions of a differential equation. The result has applications to functional transcendence, diophantine geometry, and compact complex manifolds.<br />
<br />
==November 21, 2022, <span style="color: red;">Monday</span> at 4pm [https://math.mit.edu/directory/profile.html?pid=1698 Andrei Negut] (MIT) Zoom link: [https://go.wisc.edu/andreinegut https://go.wisc.edu/andreinegut]==<br />
Hiring talk.<br />
<br />
(hosts: Arinkin, Caldararu)<br />
<br />
'''From gauge theory to geometric representation theory and back'''<br />
<br />
We start from the celebrated construction (due to Grojnowski and Nakajima) of a Heisenberg algebra action on the cohomology groups of Hilbert schemes of points on surfaces<br />
<br />
# replacing Hilbert schemes with moduli spaces of higher rank sheaves yields a computation of Nekrasov partition functions in 5d supersymmetric gauge theory, and a proof of the deformed Alday-Gaiotto-Tachikawa conjecture.<br />
# replacing cohomology by Chow groups gives a proof of the Beauville conjecture in the hyperkahler geometry of Hilbert schemes of points on K3 surfaces (with Maulik)<br />
# working with derived categories allows us to construct a detailed framework realizing categorical knot invariants in terms of the geometry of Hilbert schemes of points on the affine plane (with Gorsky and Rasmussen)<br />
<br />
==December 2, 2022, Friday at 4pm: Promit Ghosal (MIT)==<br />
'''Fractal Geometry of the KPZ equation'''<br />
<br />
The Kardar-Parisi-Zhang (KPZ) equation is a fundamental stochastic PDE related to many important models like random growth processes, Burgers turbulence, interacting particles system, random polymers etc. In this talk, we focus on how the tall peaks and deep valleys of the KPZ height function grow as time increases. In particular, we will ask what is the appropriate scaling of the peaks and valleys of the (1+1)-d KPZ equation and whether they converge to any limit under those scaling. These questions will be answered via the law of iterated logarithms and fractal dimensions of the level sets. The talk will be based on joint works with Sayan Das and Jaeyun Yi. If time permits, I will also mention an interesting story about the (2+1)-d and (3+1)-d case (work in progress with Jaeyun Yi).<br />
==December 9, 2022, Friday at 4pm: Dallas Albritton (Princeton)==<br />
(reserved by HC. contact: Stechmann)<br />
<br />
== December 12, 2022, Monday at 4pm: Laurel Ohm (Princeton) ==<br />
(reserved by HC. contact: Stechmann)<br />
<br />
== Future Colloquia ==<br />
<br />
[[Colloquia/Fall2022|Fall 2022]]<br />
<br />
[[Colloquia/Spring2023|Spring 2023]]<br />
<br />
== Past Colloquia ==<br />
[[Spring 2022 Colloquiums|Spring 2022]]<br />
<br />
[[Colloquia/Fall2021|Fall 2021]]<br />
<br />
[[Colloquia/Spring2021|Spring 2021]]<br />
<br />
[[Colloquia/Fall2020|Fall 2020]]<br />
<br />
[[Colloquia/Spring2020|Spring 2020]]<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]<br />
<br />
[[WIMAW]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Colloquia&diff=24096Colloquia2022-11-28T17:27:35Z<p>Nagreen: /* December 9, 2022, Friday at 4pm [TBD] */</p>
<hr />
<div>__NOTOC__<br />
<br />
In 2022-2023, our colloquia will be in-person talks in B239 unless otherwise stated. <br />
<br />
==September 9 , 2022, Friday at 4pm [https://math.ou.edu/~jing/ Jing Tao] (University of Oklahoma)==<br />
(host: Dymarz, Uyanik, WIMAW)<br />
<br />
'''On surface homeomorphisms'''<br />
<br />
In the 1970s, Thurston generalized the classification of self-maps of the torus to surfaces of higher genus, thus completing the work initiated by Nielsen. This is known as the Nielsen-Thurston Classification Theorem. Over the years, many alternative proofs have been obtained, using different aspects of surface theory. In this talk, I will overview the classical theory and sketch the ideas of a new proof, one that offers new insights into the hyperbolic geometry of surfaces. This is joint work with Camille Horbez.<br />
==September 23, 2022, Friday at 4pm [https://www.pabloshmerkin.org/ Pablo Shmerkin] (University of British Columbia) ==<br />
(host: Guo, Seeger)<br />
<br />
'''Incidences and line counting: from the discrete to the fractal setting'''<br />
<br />
How many lines are spanned by a set of planar points?. If the points are collinear, then the answer is clearly "one". If they are not collinear, however, several different answers exist when sets are finite and "how many" is measured by cardinality. I will discuss a bit of the history of this problem and present a recent extension to the continuum setting, obtained in collaboration with T. Orponen and H. Wang. No specialized background will be assumed.<br />
<br />
==September 30, 2022, Friday at 4pm [https://alejandraquintos.com/ Alejandra Quintos] (University of Wisconsin-Madison, Statistics) ==<br />
(host: Stovall)<br />
<br />
'''Dependent Stopping Times and an Application to Credit Risk Theory'''<br />
<br />
Stopping times are used in applications to model random arrivals. A standard assumption in many models is that the stopping times are conditionally independent, given an underlying filtration. This is a widely useful assumption, but there are circumstances where it seems to be unnecessarily strong. In the first part of the talk, we use a modified Cox construction, along with the bivariate exponential introduced by Marshall & Olkin (1967), to create a family of stopping times, which are not necessarily conditionally independent, allowing for a positive probability for them to be equal. We also present a series of results exploring the special properties of this construction.<br />
<br />
In the second part of the talk, we present an application of our model to Credit Risk. We characterize the probability of a market failure which is defined as the default of two or more globally systemically important banks (G-SIBs) in a small interval of time. The default probabilities of the G-SIBs are correlated through the possible existence of a market-wide stress event. We derive various theorems related to market failure probabilities, such as the probability of a catastrophic market failure, the impact of increasing the number of G-SIBs in an economy, and the impact of changing the initial conditions of the economy's state variables. We also show that if there are too many G-SIBs, a market failure is inevitable, i.e., the probability of a market failure tends to one as the number of G-SIBs tends to infinity.<br />
==October 7, 2022, Friday at 4pm [https://www.daniellitt.com/ Daniel Litt] (University of Toronto)==<br />
(host: Ananth Shankar)<br />
<br />
'''The search for special symmetries'''<br />
<br />
What are the canonical sets of symmetries of n-dimensional space? I'll describe the history of this question, going back to Schwarz, Fuchs, Painlevé, and others, and some new answers to it, obtained jointly with Aaron Landesman. While our results rely on low-dimensional topology, Hodge theory, and the Langlands program, and we'll get a peek into how these areas come into play, no knowledge of them will be assumed.<br />
<br />
==October 14, 2022, Friday at 4pm [https://math.sciences.ncsu.edu/people/asagema/ Andrew Sageman-Furnas] (North Carolina State)==<br />
(host: Mari-Beffa)<br />
<br />
'''Constructing isometric tori with the same curvatures'''<br />
<br />
Which data determine an immersed surface in Euclidean three-space up to rigid motion? A generic surface is locally determined by only an intrinsic metric and extrinsic mean curvature function. However, there are exceptions. These may arise in a family like the isometric family of vanishing mean curvature surfaces transforming a catenoid into a helicoid.<br />
<br />
For compact surfaces, Lawson and Tribuzy proved in 1981 that a metric and non-constant mean curvature function determine at most one immersion with genus zero, but at most two compact immersions (compact Bonnet pairs) for higher genus. In this talk, we discuss our recent construction of the first examples of compact Bonnet pairs. It uses a local classification by Kamberov, Pedit, and Pinkall in terms of isothermic surfaces. Moreover, we describe how a structure-preserving discrete theory for isothermic surfaces and Bonnet pairs led to this discovery.<br />
<br />
The smooth theory is joint work with Alexander Bobenko and Tim Hoffmann and the discrete theory is joint work with Tim Hoffmann and Max Wardetzky.<br />
<br />
== October 20, 2022, Thursday at 4pm, VV911 [https://tavarelab.cancerdynamics.columbia.edu/ Simon Tavaré] (Columbia University) ==<br />
(host: Kurtz, Roch)<br />
<br />
''Note the unusual time and room!''<br />
<br />
'''An introduction to counts-of-counts data'''<br />
<br />
Counts-of-counts data arise in many areas of biology and medicine, and have been studied by statisticians since the 1940s. One of the first examples, discussed by R. A. Fisher and collaborators in 1943 [1], concerns estimation of the number of unobserved species based on summary counts of the number of species observed once, twice, … in a sample of specimens. The data are summarized by the numbers ''C<sub>1</sub>, C<sub>2</sub>, …'' of species represented once, twice, … in a sample of size<br />
<br />
''N = C<sub>1</sub> + 2 C<sub>2</sub> + 3 C<sub>3</sub> + <sup>….</sup>'' containing ''S = C<sub>1</sub> + C<sub>2</sub> + <sup>…</sup>'' species; the vector ''C ='' ''(C<sub>1</sub>, C<sub>2</sub>, …)'' gives the counts-of-counts. Other examples include the frequencies of the distinct alleles in a human genetics sample, the counts of distinct variants of the SARS-CoV-2 S protein obtained from consensus sequencing experiments, counts of sizes of components in certain combinatorial structures [2], and counts of the numbers of SNVs arising in one cell, two cells, … in a cancer sequencing experiment.<br />
<br />
In this talk I will outline some of the stochastic models used to model the distribution of ''C,'' and some of the inferential issues that come from estimating the parameters of these models. I will touch on the celebrated Ewens Sampling Formula [3] and Fisher’s multiple sampling problem concerning the variance expected between values of ''S'' in samples taken from the same population [3]. Variants of birth-death-immigration processes can be used, for example when different variants grow at different rates. Some of these models are mechanistic in spirit, others more statistical. For example, a non-mechanistic model is useful for describing the arrival of covid sequences at a database. Sequences arrive one at a time, and are either a new variant, or a copy of a variant that has appeared before. The classical Yule process with immigration provides a starting point to model this process, as I will illustrate.<br />
<br />
''References''<br />
<br />
[1] Fisher RA, Corbet AS & Williams CB. J Animal Ecology, 12, 1943<br />
<br />
[2] Arratia R, Barbour AD & Tavaré S. ''Logarithmic Combinatorial Structures,'' EMS, 2002<br />
<br />
[3] Ewens WJ. Theoret Popul Biol, 3, 1972<br />
<br />
[4] Da Silva P, Jamshidpey A, McCullagh P & Tavaré S. Bernoulli Journal, in press, 2022 (online)<br />
<br />
==October 21, 2022, Friday at 4pm [https://web.ma.utexas.edu/users/ntran/ Ngoc Mai Tran] (Texas)==<br />
(host: Rodriguez)<br />
<br />
'''Forecast science, learn hidden networks and settle economics conjectures with combinatorics, geometry and probability.''' <br />
<br />
In many problems, one observes noisy data coming from a hidden or complex combinatorial structure. My research aims to understand and exploit such structures to arrive at an efficient and optimal solution. I will showcase a few successes, achieved with different tools, from different different fields: networks forecasting, hydrology, and auction theory. Then I will outline some open questions in each field. <br />
<br />
==October 28, 2022, Friday at 4pm [https://people.math.wisc.edu/~qinli/ Qin Li] (UW)==<br />
'''Multiscale inverse problem, from Schroedinger to Newton to Boltzmann'''<br />
<br />
Inverse problems are ubiquitous. We probe the media with sources and measure the outputs, to infer the media information. At the scale of quantum, classical, statistical and fluid, we face inverse Schroedinger, inverse Newton’s second law, inverse Boltzmann problem, and inverse diffusion respectively. The universe, however, expects a universal mathematical description, as Hilbert proposed in 1900. In this talk, we discuss the connection between these problems. We will give arguments for justifying that these are the same problem merely represented at different scales. It is a light-hearted talk, and I will mostly focus on the story instead of the derivation. PDE background is appreciated but not necessary.<br />
<br />
== November 7, 2022, Monday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures<br />
<br />
(host: Yang).<br />
<br />
'''Private AI: Machine Learning on Encrypted Data'''<br />
<br />
As the world adopts Artificial Intelligence, the privacy risks are many. AI can improve our lives, but may leak our private data. Private AI is based on Homomorphic Encryption (HE), a new encryption paradigm which allows the cloud to operate on private data in encrypted form, without ever decrypting it, enabling private training and private prediction. Our 2016 ICML CryptoNets paper showed for the first time that it was possible to evaluate neural nets on homomorphically encrypted data, and opened new research directions combining machine learning and cryptography. The security of Homomorphic Encryption is based on hard problems in mathematics involving lattices, recently standardized by NIST for post-quantum cryptography. This talk will explain Homomorphic Encryption, Private AI, and explain HE in action.<br />
<br />
== November 8, 2022, Tuesday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures in VV911. ''Note: unusual room.''<br />
<br />
(host: Yang).<br />
<br />
'''Artificial Intelligence & Cryptography: Privacy and Security in the AI era'''<br />
<br />
How is Artificial Intelligence changing your life and the world? How do you expect your data to be kept secure and private in the future? Artificial intelligence (AI) refers to the science of utilizing data to formulate mathematical models that predict outcomes with high assurance. Such predictions can be used to make decisions automatically or give recommendations with high confidence. Cryptography is the science of protecting the privacy and security of data. This talk will explain the dynamic relationship between cryptography and AI and how AI can be used to attack post-quantum cryptosystems.<br />
<br />
The first talk is based on my 2019 ICIAM Plenary Lecture and the second one is based on my 2022 SIAM Block Prize Lecture.<br />
<br />
== November 11, 2022, Friday at 4pm [http://users.cms.caltech.edu/~jtropp/ Joel Tropp] (Caltech)==<br />
This is the Annual LAA lecture. See [https://math.wisc.edu/laa-lecture/ this] for its history.<br />
<br />
(host: Qin, Jordan)<br />
<br />
'''Rocket-propelled Cholesky: Addressing the challenges of large-scale kernel computations'''<br />
<br />
Kernel methods are used for prediction and clustering in many data science and scientific computing applications, but applying kernel methods to a large number of data points N is expensive due to the high cost of manipulating the N x N kernel matrix. A basic approach for speeding up kernel computations is low-rank approximation, in which we replace the kernel matrix A with a factorized approximation that can be stored and manipulated more cheaply. When the kernel matrix A has rapidly decaying eigenvalues, mathematical existence proofs guarantee that A can be accurately approximated using a constant number of columns (without ever looking at the full matrix). Nevertheless, for a long time designing a practical and provably justified algorithm to select the appropriate columns proved challenging.<br />
<br />
Recently, we introduced RPCholesky ("randomly pivoted" or "rocket-propelled" Cholesky), a natural algorithm for approximating an N x N positive semidefinite matrix using k adaptively sampled columns. RPCholesky can be implemented with just a few lines of code; it requires only (k+1)N entry evaluations and O(k^2 N) additional arithmetic operations. In experiments, RPCholesky matches or improves on the performance of alternative algorithms for low-rank psd approximation. Moreover, RPCholesky provably achieves near-optimal approximation guarantees. The simplicity, effectiveness, and robustness of this algorithm strongly support its use for large-scale kernel computations.<br />
<br />
Joint work with Yifan Chen, Ethan Epperly, and Rob Webber. Available at arXiv:2207.06503.<br />
<br />
==November 18, 2022, Friday at 4pm [http://homepages.math.uic.edu/~freitag/index.html Jim Freitag] (U of Illinois-Chicago) Zoom link: https://go.wisc.edu/jimfreitag<nowiki/>==<br />
'''Now available:''' [https://people.math.wisc.edu/logic/talks/221118-Freitag.mp4 Recording] and [https://people.math.wisc.edu/logic/talks/221118-Freitag.pdf Slides]<br />
<br />
(hosts: Lempp, Andrews)<br />
<br />
'''When any three solutions are independent'''<br />
<br />
In this talk, we'll talk about a surprising recent result about the algebraic relations between solutions of a differential equation. The result has applications to functional transcendence, diophantine geometry, and compact complex manifolds.<br />
<br />
==November 21, 2022, <span style="color: red;">Monday</span> at 4pm [https://math.mit.edu/directory/profile.html?pid=1698 Andrei Negut] (MIT) Zoom link: [https://go.wisc.edu/andreinegut https://go.wisc.edu/andreinegut]==<br />
Hiring talk.<br />
<br />
(hosts: Arinkin, Caldararu)<br />
<br />
'''From gauge theory to geometric representation theory and back'''<br />
<br />
We start from the celebrated construction (due to Grojnowski and Nakajima) of a Heisenberg algebra action on the cohomology groups of Hilbert schemes of points on surfaces<br />
<br />
# replacing Hilbert schemes with moduli spaces of higher rank sheaves yields a computation of Nekrasov partition functions in 5d supersymmetric gauge theory, and a proof of the deformed Alday-Gaiotto-Tachikawa conjecture.<br />
# replacing cohomology by Chow groups gives a proof of the Beauville conjecture in the hyperkahler geometry of Hilbert schemes of points on K3 surfaces (with Maulik)<br />
# working with derived categories allows us to construct a detailed framework realizing categorical knot invariants in terms of the geometry of Hilbert schemes of points on the affine plane (with Gorsky and Rasmussen)<br />
<br />
==December 2, 2022, Friday at 4pm: Promit Ghosal (MIT)==<br />
'''Fractal Geometry of the KPZ equation'''<br />
<br />
The Kardar-Parisi-Zhang (KPZ) equation is a fundamental stochastic PDE related to many important models like random growth processes, Burgers turbulence, interacting particles system, random polymers etc. In this talk, we focus on how the tall peaks and deep valleys of the KPZ height function grow as time increases. In particular, we will ask what is the appropriate scaling of the peaks and valleys of the (1+1)-d KPZ equation and whether they converge to any limit under those scaling. These questions will be answered via the law of iterated logarithms and fractal dimensions of the level sets. The talk will be based on joint works with Sayan Das and Jaeyun Yi. If time permits, I will also mention an interesting story about the (2+1)-d and (3+1)-d case (work in progress with Jaeyun Yi).<br />
==December 9, 2022, Friday at 4pm: Dallas Albritton (Princeton)==<br />
(reserved by HC. contact: Stechmann)<br />
== Future Colloquia ==<br />
<br />
[[Colloquia/Fall2022|Fall 2022]]<br />
<br />
[[Colloquia/Spring2023|Spring 2023]]<br />
<br />
== Past Colloquia ==<br />
[[Spring 2022 Colloquiums|Spring 2022]]<br />
<br />
[[Colloquia/Fall2021|Fall 2021]]<br />
<br />
[[Colloquia/Spring2021|Spring 2021]]<br />
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[[Colloquia/Fall2020|Fall 2020]]<br />
<br />
[[Colloquia/Spring2020|Spring 2020]]<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
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[[Colloquia 2012-2013|Spring 2013]]<br />
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[[Colloquia 2012-2013#Fall 2012|Fall 2012]]<br />
<br />
[[WIMAW]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Colloquia&diff=24087Colloquia2022-11-26T14:55:43Z<p>Nagreen: /* December 2, 2022, Friday at 4pm [TBD] */</p>
<hr />
<div>__NOTOC__<br />
<br />
In 2022-2023, our colloquia will be in-person talks in B239 unless otherwise stated. <br />
<br />
==September 9 , 2022, Friday at 4pm [https://math.ou.edu/~jing/ Jing Tao] (University of Oklahoma)==<br />
(host: Dymarz, Uyanik, WIMAW)<br />
<br />
'''On surface homeomorphisms'''<br />
<br />
In the 1970s, Thurston generalized the classification of self-maps of the torus to surfaces of higher genus, thus completing the work initiated by Nielsen. This is known as the Nielsen-Thurston Classification Theorem. Over the years, many alternative proofs have been obtained, using different aspects of surface theory. In this talk, I will overview the classical theory and sketch the ideas of a new proof, one that offers new insights into the hyperbolic geometry of surfaces. This is joint work with Camille Horbez.<br />
==September 23, 2022, Friday at 4pm [https://www.pabloshmerkin.org/ Pablo Shmerkin] (University of British Columbia) ==<br />
(host: Guo, Seeger)<br />
<br />
'''Incidences and line counting: from the discrete to the fractal setting'''<br />
<br />
How many lines are spanned by a set of planar points?. If the points are collinear, then the answer is clearly "one". If they are not collinear, however, several different answers exist when sets are finite and "how many" is measured by cardinality. I will discuss a bit of the history of this problem and present a recent extension to the continuum setting, obtained in collaboration with T. Orponen and H. Wang. No specialized background will be assumed.<br />
<br />
==September 30, 2022, Friday at 4pm [https://alejandraquintos.com/ Alejandra Quintos] (University of Wisconsin-Madison, Statistics) ==<br />
(host: Stovall)<br />
<br />
'''Dependent Stopping Times and an Application to Credit Risk Theory'''<br />
<br />
Stopping times are used in applications to model random arrivals. A standard assumption in many models is that the stopping times are conditionally independent, given an underlying filtration. This is a widely useful assumption, but there are circumstances where it seems to be unnecessarily strong. In the first part of the talk, we use a modified Cox construction, along with the bivariate exponential introduced by Marshall & Olkin (1967), to create a family of stopping times, which are not necessarily conditionally independent, allowing for a positive probability for them to be equal. We also present a series of results exploring the special properties of this construction.<br />
<br />
In the second part of the talk, we present an application of our model to Credit Risk. We characterize the probability of a market failure which is defined as the default of two or more globally systemically important banks (G-SIBs) in a small interval of time. The default probabilities of the G-SIBs are correlated through the possible existence of a market-wide stress event. We derive various theorems related to market failure probabilities, such as the probability of a catastrophic market failure, the impact of increasing the number of G-SIBs in an economy, and the impact of changing the initial conditions of the economy's state variables. We also show that if there are too many G-SIBs, a market failure is inevitable, i.e., the probability of a market failure tends to one as the number of G-SIBs tends to infinity.<br />
==October 7, 2022, Friday at 4pm [https://www.daniellitt.com/ Daniel Litt] (University of Toronto)==<br />
(host: Ananth Shankar)<br />
<br />
'''The search for special symmetries'''<br />
<br />
What are the canonical sets of symmetries of n-dimensional space? I'll describe the history of this question, going back to Schwarz, Fuchs, Painlevé, and others, and some new answers to it, obtained jointly with Aaron Landesman. While our results rely on low-dimensional topology, Hodge theory, and the Langlands program, and we'll get a peek into how these areas come into play, no knowledge of them will be assumed.<br />
<br />
==October 14, 2022, Friday at 4pm [https://math.sciences.ncsu.edu/people/asagema/ Andrew Sageman-Furnas] (North Carolina State)==<br />
(host: Mari-Beffa)<br />
<br />
'''Constructing isometric tori with the same curvatures'''<br />
<br />
Which data determine an immersed surface in Euclidean three-space up to rigid motion? A generic surface is locally determined by only an intrinsic metric and extrinsic mean curvature function. However, there are exceptions. These may arise in a family like the isometric family of vanishing mean curvature surfaces transforming a catenoid into a helicoid.<br />
<br />
For compact surfaces, Lawson and Tribuzy proved in 1981 that a metric and non-constant mean curvature function determine at most one immersion with genus zero, but at most two compact immersions (compact Bonnet pairs) for higher genus. In this talk, we discuss our recent construction of the first examples of compact Bonnet pairs. It uses a local classification by Kamberov, Pedit, and Pinkall in terms of isothermic surfaces. Moreover, we describe how a structure-preserving discrete theory for isothermic surfaces and Bonnet pairs led to this discovery.<br />
<br />
The smooth theory is joint work with Alexander Bobenko and Tim Hoffmann and the discrete theory is joint work with Tim Hoffmann and Max Wardetzky.<br />
<br />
== October 20, 2022, Thursday at 4pm, VV911 [https://tavarelab.cancerdynamics.columbia.edu/ Simon Tavaré] (Columbia University) ==<br />
(host: Kurtz, Roch)<br />
<br />
''Note the unusual time and room!''<br />
<br />
'''An introduction to counts-of-counts data'''<br />
<br />
Counts-of-counts data arise in many areas of biology and medicine, and have been studied by statisticians since the 1940s. One of the first examples, discussed by R. A. Fisher and collaborators in 1943 [1], concerns estimation of the number of unobserved species based on summary counts of the number of species observed once, twice, … in a sample of specimens. The data are summarized by the numbers ''C<sub>1</sub>, C<sub>2</sub>, …'' of species represented once, twice, … in a sample of size<br />
<br />
''N = C<sub>1</sub> + 2 C<sub>2</sub> + 3 C<sub>3</sub> + <sup>….</sup>'' containing ''S = C<sub>1</sub> + C<sub>2</sub> + <sup>…</sup>'' species; the vector ''C ='' ''(C<sub>1</sub>, C<sub>2</sub>, …)'' gives the counts-of-counts. Other examples include the frequencies of the distinct alleles in a human genetics sample, the counts of distinct variants of the SARS-CoV-2 S protein obtained from consensus sequencing experiments, counts of sizes of components in certain combinatorial structures [2], and counts of the numbers of SNVs arising in one cell, two cells, … in a cancer sequencing experiment.<br />
<br />
In this talk I will outline some of the stochastic models used to model the distribution of ''C,'' and some of the inferential issues that come from estimating the parameters of these models. I will touch on the celebrated Ewens Sampling Formula [3] and Fisher’s multiple sampling problem concerning the variance expected between values of ''S'' in samples taken from the same population [3]. Variants of birth-death-immigration processes can be used, for example when different variants grow at different rates. Some of these models are mechanistic in spirit, others more statistical. For example, a non-mechanistic model is useful for describing the arrival of covid sequences at a database. Sequences arrive one at a time, and are either a new variant, or a copy of a variant that has appeared before. The classical Yule process with immigration provides a starting point to model this process, as I will illustrate.<br />
<br />
''References''<br />
<br />
[1] Fisher RA, Corbet AS & Williams CB. J Animal Ecology, 12, 1943<br />
<br />
[2] Arratia R, Barbour AD & Tavaré S. ''Logarithmic Combinatorial Structures,'' EMS, 2002<br />
<br />
[3] Ewens WJ. Theoret Popul Biol, 3, 1972<br />
<br />
[4] Da Silva P, Jamshidpey A, McCullagh P & Tavaré S. Bernoulli Journal, in press, 2022 (online)<br />
<br />
==October 21, 2022, Friday at 4pm [https://web.ma.utexas.edu/users/ntran/ Ngoc Mai Tran] (Texas)==<br />
(host: Rodriguez)<br />
<br />
'''Forecast science, learn hidden networks and settle economics conjectures with combinatorics, geometry and probability.''' <br />
<br />
In many problems, one observes noisy data coming from a hidden or complex combinatorial structure. My research aims to understand and exploit such structures to arrive at an efficient and optimal solution. I will showcase a few successes, achieved with different tools, from different different fields: networks forecasting, hydrology, and auction theory. Then I will outline some open questions in each field. <br />
<br />
==October 28, 2022, Friday at 4pm [https://people.math.wisc.edu/~qinli/ Qin Li] (UW)==<br />
'''Multiscale inverse problem, from Schroedinger to Newton to Boltzmann'''<br />
<br />
Inverse problems are ubiquitous. We probe the media with sources and measure the outputs, to infer the media information. At the scale of quantum, classical, statistical and fluid, we face inverse Schroedinger, inverse Newton’s second law, inverse Boltzmann problem, and inverse diffusion respectively. The universe, however, expects a universal mathematical description, as Hilbert proposed in 1900. In this talk, we discuss the connection between these problems. We will give arguments for justifying that these are the same problem merely represented at different scales. It is a light-hearted talk, and I will mostly focus on the story instead of the derivation. PDE background is appreciated but not necessary.<br />
<br />
== November 7, 2022, Monday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures<br />
<br />
(host: Yang).<br />
<br />
'''Private AI: Machine Learning on Encrypted Data'''<br />
<br />
As the world adopts Artificial Intelligence, the privacy risks are many. AI can improve our lives, but may leak our private data. Private AI is based on Homomorphic Encryption (HE), a new encryption paradigm which allows the cloud to operate on private data in encrypted form, without ever decrypting it, enabling private training and private prediction. Our 2016 ICML CryptoNets paper showed for the first time that it was possible to evaluate neural nets on homomorphically encrypted data, and opened new research directions combining machine learning and cryptography. The security of Homomorphic Encryption is based on hard problems in mathematics involving lattices, recently standardized by NIST for post-quantum cryptography. This talk will explain Homomorphic Encryption, Private AI, and explain HE in action.<br />
<br />
== November 8, 2022, Tuesday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures in VV911. ''Note: unusual room.''<br />
<br />
(host: Yang).<br />
<br />
'''Artificial Intelligence & Cryptography: Privacy and Security in the AI era'''<br />
<br />
How is Artificial Intelligence changing your life and the world? How do you expect your data to be kept secure and private in the future? Artificial intelligence (AI) refers to the science of utilizing data to formulate mathematical models that predict outcomes with high assurance. Such predictions can be used to make decisions automatically or give recommendations with high confidence. Cryptography is the science of protecting the privacy and security of data. This talk will explain the dynamic relationship between cryptography and AI and how AI can be used to attack post-quantum cryptosystems.<br />
<br />
The first talk is based on my 2019 ICIAM Plenary Lecture and the second one is based on my 2022 SIAM Block Prize Lecture.<br />
<br />
== November 11, 2022, Friday at 4pm [http://users.cms.caltech.edu/~jtropp/ Joel Tropp] (Caltech)==<br />
This is the Annual LAA lecture. See [https://math.wisc.edu/laa-lecture/ this] for its history.<br />
<br />
(host: Qin, Jordan)<br />
<br />
'''Rocket-propelled Cholesky: Addressing the challenges of large-scale kernel computations'''<br />
<br />
Kernel methods are used for prediction and clustering in many data science and scientific computing applications, but applying kernel methods to a large number of data points N is expensive due to the high cost of manipulating the N x N kernel matrix. A basic approach for speeding up kernel computations is low-rank approximation, in which we replace the kernel matrix A with a factorized approximation that can be stored and manipulated more cheaply. When the kernel matrix A has rapidly decaying eigenvalues, mathematical existence proofs guarantee that A can be accurately approximated using a constant number of columns (without ever looking at the full matrix). Nevertheless, for a long time designing a practical and provably justified algorithm to select the appropriate columns proved challenging.<br />
<br />
Recently, we introduced RPCholesky ("randomly pivoted" or "rocket-propelled" Cholesky), a natural algorithm for approximating an N x N positive semidefinite matrix using k adaptively sampled columns. RPCholesky can be implemented with just a few lines of code; it requires only (k+1)N entry evaluations and O(k^2 N) additional arithmetic operations. In experiments, RPCholesky matches or improves on the performance of alternative algorithms for low-rank psd approximation. Moreover, RPCholesky provably achieves near-optimal approximation guarantees. The simplicity, effectiveness, and robustness of this algorithm strongly support its use for large-scale kernel computations.<br />
<br />
Joint work with Yifan Chen, Ethan Epperly, and Rob Webber. Available at arXiv:2207.06503.<br />
<br />
==November 18, 2022, Friday at 4pm [http://homepages.math.uic.edu/~freitag/index.html Jim Freitag] (U of Illinois-Chicago) Zoom link: https://go.wisc.edu/jimfreitag<nowiki/>==<br />
'''Now available:''' [https://people.math.wisc.edu/logic/talks/221118-Freitag.mp4 Recording] and [https://people.math.wisc.edu/logic/talks/221118-Freitag.pdf Slides]<br />
<br />
(hosts: Lempp, Andrews)<br />
<br />
'''When any three solutions are independent'''<br />
<br />
In this talk, we'll talk about a surprising recent result about the algebraic relations between solutions of a differential equation. The result has applications to functional transcendence, diophantine geometry, and compact complex manifolds.<br />
<br />
==November 21, 2022, <span style="color: red;">Monday</span> at 4pm [https://math.mit.edu/directory/profile.html?pid=1698 Andrei Negut] (MIT) Zoom link: [https://go.wisc.edu/andreinegut https://go.wisc.edu/andreinegut]==<br />
Hiring talk.<br />
<br />
(hosts: Arinkin, Caldararu)<br />
<br />
'''From gauge theory to geometric representation theory and back'''<br />
<br />
We start from the celebrated construction (due to Grojnowski and Nakajima) of a Heisenberg algebra action on the cohomology groups of Hilbert schemes of points on surfaces<br />
<br />
# replacing Hilbert schemes with moduli spaces of higher rank sheaves yields a computation of Nekrasov partition functions in 5d supersymmetric gauge theory, and a proof of the deformed Alday-Gaiotto-Tachikawa conjecture.<br />
# replacing cohomology by Chow groups gives a proof of the Beauville conjecture in the hyperkahler geometry of Hilbert schemes of points on K3 surfaces (with Maulik)<br />
# working with derived categories allows us to construct a detailed framework realizing categorical knot invariants in terms of the geometry of Hilbert schemes of points on the affine plane (with Gorsky and Rasmussen)<br />
<br />
==December 2, 2022, Friday at 4pm: Promit Ghosal (MIT)==<br />
<blockquote>'''Fractal Geometry of the KPZ equation'''<br />
<br />
''Abstract:'' The Kardar-Parisi-Zhang (KPZ) equation is a fundamental stochastic PDE related to many important models like random growth processes, Burgers turbulence, interacting particles system, random polymers etc. In this talk, we focus on how the tall peaks and deep valleys of the KPZ height function grow as time increases. In particular, we will ask what is the appropriate scaling of the peaks and valleys of the (1+1)-d KPZ equation and whether they converge to any limit under those scaling. These questions will be answered via the law of iterated logarithms and fractal dimensions of the level sets. The talk will be based on joint works with Sayan Das and Jaeyun Yi. If time permits, I will also mention an interesting story about the (2+1)-d and (3+1)-d case (work in progress with Jaeyun Yi).</blockquote><br />
<br />
==December 9, 2022, Friday at 4pm [TBD]==<br />
(reserved by HC. contact: Stechmann)<br />
== Future Colloquia ==<br />
<br />
[[Colloquia/Fall2022|Fall 2022]]<br />
<br />
[[Colloquia/Spring2023|Spring 2023]]<br />
<br />
== Past Colloquia ==<br />
[[Spring 2022 Colloquiums|Spring 2022]]<br />
<br />
[[Colloquia/Fall2021|Fall 2021]]<br />
<br />
[[Colloquia/Spring2021|Spring 2021]]<br />
<br />
[[Colloquia/Fall2020|Fall 2020]]<br />
<br />
[[Colloquia/Spring2020|Spring 2020]]<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]<br />
<br />
[[WIMAW]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Colloquia&diff=24086Colloquia2022-11-26T14:53:58Z<p>Nagreen: Added abstract</p>
<hr />
<div>__NOTOC__<br />
<br />
In 2022-2023, our colloquia will be in-person talks in B239 unless otherwise stated. <br />
<br />
==September 9 , 2022, Friday at 4pm [https://math.ou.edu/~jing/ Jing Tao] (University of Oklahoma)==<br />
(host: Dymarz, Uyanik, WIMAW)<br />
<br />
'''On surface homeomorphisms'''<br />
<br />
In the 1970s, Thurston generalized the classification of self-maps of the torus to surfaces of higher genus, thus completing the work initiated by Nielsen. This is known as the Nielsen-Thurston Classification Theorem. Over the years, many alternative proofs have been obtained, using different aspects of surface theory. In this talk, I will overview the classical theory and sketch the ideas of a new proof, one that offers new insights into the hyperbolic geometry of surfaces. This is joint work with Camille Horbez.<br />
==September 23, 2022, Friday at 4pm [https://www.pabloshmerkin.org/ Pablo Shmerkin] (University of British Columbia) ==<br />
(host: Guo, Seeger)<br />
<br />
'''Incidences and line counting: from the discrete to the fractal setting'''<br />
<br />
How many lines are spanned by a set of planar points?. If the points are collinear, then the answer is clearly "one". If they are not collinear, however, several different answers exist when sets are finite and "how many" is measured by cardinality. I will discuss a bit of the history of this problem and present a recent extension to the continuum setting, obtained in collaboration with T. Orponen and H. Wang. No specialized background will be assumed.<br />
<br />
==September 30, 2022, Friday at 4pm [https://alejandraquintos.com/ Alejandra Quintos] (University of Wisconsin-Madison, Statistics) ==<br />
(host: Stovall)<br />
<br />
'''Dependent Stopping Times and an Application to Credit Risk Theory'''<br />
<br />
Stopping times are used in applications to model random arrivals. A standard assumption in many models is that the stopping times are conditionally independent, given an underlying filtration. This is a widely useful assumption, but there are circumstances where it seems to be unnecessarily strong. In the first part of the talk, we use a modified Cox construction, along with the bivariate exponential introduced by Marshall & Olkin (1967), to create a family of stopping times, which are not necessarily conditionally independent, allowing for a positive probability for them to be equal. We also present a series of results exploring the special properties of this construction.<br />
<br />
In the second part of the talk, we present an application of our model to Credit Risk. We characterize the probability of a market failure which is defined as the default of two or more globally systemically important banks (G-SIBs) in a small interval of time. The default probabilities of the G-SIBs are correlated through the possible existence of a market-wide stress event. We derive various theorems related to market failure probabilities, such as the probability of a catastrophic market failure, the impact of increasing the number of G-SIBs in an economy, and the impact of changing the initial conditions of the economy's state variables. We also show that if there are too many G-SIBs, a market failure is inevitable, i.e., the probability of a market failure tends to one as the number of G-SIBs tends to infinity.<br />
==October 7, 2022, Friday at 4pm [https://www.daniellitt.com/ Daniel Litt] (University of Toronto)==<br />
(host: Ananth Shankar)<br />
<br />
'''The search for special symmetries'''<br />
<br />
What are the canonical sets of symmetries of n-dimensional space? I'll describe the history of this question, going back to Schwarz, Fuchs, Painlevé, and others, and some new answers to it, obtained jointly with Aaron Landesman. While our results rely on low-dimensional topology, Hodge theory, and the Langlands program, and we'll get a peek into how these areas come into play, no knowledge of them will be assumed.<br />
<br />
==October 14, 2022, Friday at 4pm [https://math.sciences.ncsu.edu/people/asagema/ Andrew Sageman-Furnas] (North Carolina State)==<br />
(host: Mari-Beffa)<br />
<br />
'''Constructing isometric tori with the same curvatures'''<br />
<br />
Which data determine an immersed surface in Euclidean three-space up to rigid motion? A generic surface is locally determined by only an intrinsic metric and extrinsic mean curvature function. However, there are exceptions. These may arise in a family like the isometric family of vanishing mean curvature surfaces transforming a catenoid into a helicoid.<br />
<br />
For compact surfaces, Lawson and Tribuzy proved in 1981 that a metric and non-constant mean curvature function determine at most one immersion with genus zero, but at most two compact immersions (compact Bonnet pairs) for higher genus. In this talk, we discuss our recent construction of the first examples of compact Bonnet pairs. It uses a local classification by Kamberov, Pedit, and Pinkall in terms of isothermic surfaces. Moreover, we describe how a structure-preserving discrete theory for isothermic surfaces and Bonnet pairs led to this discovery.<br />
<br />
The smooth theory is joint work with Alexander Bobenko and Tim Hoffmann and the discrete theory is joint work with Tim Hoffmann and Max Wardetzky.<br />
<br />
== October 20, 2022, Thursday at 4pm, VV911 [https://tavarelab.cancerdynamics.columbia.edu/ Simon Tavaré] (Columbia University) ==<br />
(host: Kurtz, Roch)<br />
<br />
''Note the unusual time and room!''<br />
<br />
'''An introduction to counts-of-counts data'''<br />
<br />
Counts-of-counts data arise in many areas of biology and medicine, and have been studied by statisticians since the 1940s. One of the first examples, discussed by R. A. Fisher and collaborators in 1943 [1], concerns estimation of the number of unobserved species based on summary counts of the number of species observed once, twice, … in a sample of specimens. The data are summarized by the numbers ''C<sub>1</sub>, C<sub>2</sub>, …'' of species represented once, twice, … in a sample of size<br />
<br />
''N = C<sub>1</sub> + 2 C<sub>2</sub> + 3 C<sub>3</sub> + <sup>….</sup>'' containing ''S = C<sub>1</sub> + C<sub>2</sub> + <sup>…</sup>'' species; the vector ''C ='' ''(C<sub>1</sub>, C<sub>2</sub>, …)'' gives the counts-of-counts. Other examples include the frequencies of the distinct alleles in a human genetics sample, the counts of distinct variants of the SARS-CoV-2 S protein obtained from consensus sequencing experiments, counts of sizes of components in certain combinatorial structures [2], and counts of the numbers of SNVs arising in one cell, two cells, … in a cancer sequencing experiment.<br />
<br />
In this talk I will outline some of the stochastic models used to model the distribution of ''C,'' and some of the inferential issues that come from estimating the parameters of these models. I will touch on the celebrated Ewens Sampling Formula [3] and Fisher’s multiple sampling problem concerning the variance expected between values of ''S'' in samples taken from the same population [3]. Variants of birth-death-immigration processes can be used, for example when different variants grow at different rates. Some of these models are mechanistic in spirit, others more statistical. For example, a non-mechanistic model is useful for describing the arrival of covid sequences at a database. Sequences arrive one at a time, and are either a new variant, or a copy of a variant that has appeared before. The classical Yule process with immigration provides a starting point to model this process, as I will illustrate.<br />
<br />
''References''<br />
<br />
[1] Fisher RA, Corbet AS & Williams CB. J Animal Ecology, 12, 1943<br />
<br />
[2] Arratia R, Barbour AD & Tavaré S. ''Logarithmic Combinatorial Structures,'' EMS, 2002<br />
<br />
[3] Ewens WJ. Theoret Popul Biol, 3, 1972<br />
<br />
[4] Da Silva P, Jamshidpey A, McCullagh P & Tavaré S. Bernoulli Journal, in press, 2022 (online)<br />
<br />
==October 21, 2022, Friday at 4pm [https://web.ma.utexas.edu/users/ntran/ Ngoc Mai Tran] (Texas)==<br />
(host: Rodriguez)<br />
<br />
'''Forecast science, learn hidden networks and settle economics conjectures with combinatorics, geometry and probability.''' <br />
<br />
In many problems, one observes noisy data coming from a hidden or complex combinatorial structure. My research aims to understand and exploit such structures to arrive at an efficient and optimal solution. I will showcase a few successes, achieved with different tools, from different different fields: networks forecasting, hydrology, and auction theory. Then I will outline some open questions in each field. <br />
<br />
==October 28, 2022, Friday at 4pm [https://people.math.wisc.edu/~qinli/ Qin Li] (UW)==<br />
'''Multiscale inverse problem, from Schroedinger to Newton to Boltzmann'''<br />
<br />
Inverse problems are ubiquitous. We probe the media with sources and measure the outputs, to infer the media information. At the scale of quantum, classical, statistical and fluid, we face inverse Schroedinger, inverse Newton’s second law, inverse Boltzmann problem, and inverse diffusion respectively. The universe, however, expects a universal mathematical description, as Hilbert proposed in 1900. In this talk, we discuss the connection between these problems. We will give arguments for justifying that these are the same problem merely represented at different scales. It is a light-hearted talk, and I will mostly focus on the story instead of the derivation. PDE background is appreciated but not necessary.<br />
<br />
== November 7, 2022, Monday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures<br />
<br />
(host: Yang).<br />
<br />
'''Private AI: Machine Learning on Encrypted Data'''<br />
<br />
As the world adopts Artificial Intelligence, the privacy risks are many. AI can improve our lives, but may leak our private data. Private AI is based on Homomorphic Encryption (HE), a new encryption paradigm which allows the cloud to operate on private data in encrypted form, without ever decrypting it, enabling private training and private prediction. Our 2016 ICML CryptoNets paper showed for the first time that it was possible to evaluate neural nets on homomorphically encrypted data, and opened new research directions combining machine learning and cryptography. The security of Homomorphic Encryption is based on hard problems in mathematics involving lattices, recently standardized by NIST for post-quantum cryptography. This talk will explain Homomorphic Encryption, Private AI, and explain HE in action.<br />
<br />
== November 8, 2022, Tuesday at 4pm [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==<br />
Distinguished lectures in VV911. ''Note: unusual room.''<br />
<br />
(host: Yang).<br />
<br />
'''Artificial Intelligence & Cryptography: Privacy and Security in the AI era'''<br />
<br />
How is Artificial Intelligence changing your life and the world? How do you expect your data to be kept secure and private in the future? Artificial intelligence (AI) refers to the science of utilizing data to formulate mathematical models that predict outcomes with high assurance. Such predictions can be used to make decisions automatically or give recommendations with high confidence. Cryptography is the science of protecting the privacy and security of data. This talk will explain the dynamic relationship between cryptography and AI and how AI can be used to attack post-quantum cryptosystems.<br />
<br />
The first talk is based on my 2019 ICIAM Plenary Lecture and the second one is based on my 2022 SIAM Block Prize Lecture.<br />
<br />
== November 11, 2022, Friday at 4pm [http://users.cms.caltech.edu/~jtropp/ Joel Tropp] (Caltech)==<br />
This is the Annual LAA lecture. See [https://math.wisc.edu/laa-lecture/ this] for its history.<br />
<br />
(host: Qin, Jordan)<br />
<br />
'''Rocket-propelled Cholesky: Addressing the challenges of large-scale kernel computations'''<br />
<br />
Kernel methods are used for prediction and clustering in many data science and scientific computing applications, but applying kernel methods to a large number of data points N is expensive due to the high cost of manipulating the N x N kernel matrix. A basic approach for speeding up kernel computations is low-rank approximation, in which we replace the kernel matrix A with a factorized approximation that can be stored and manipulated more cheaply. When the kernel matrix A has rapidly decaying eigenvalues, mathematical existence proofs guarantee that A can be accurately approximated using a constant number of columns (without ever looking at the full matrix). Nevertheless, for a long time designing a practical and provably justified algorithm to select the appropriate columns proved challenging.<br />
<br />
Recently, we introduced RPCholesky ("randomly pivoted" or "rocket-propelled" Cholesky), a natural algorithm for approximating an N x N positive semidefinite matrix using k adaptively sampled columns. RPCholesky can be implemented with just a few lines of code; it requires only (k+1)N entry evaluations and O(k^2 N) additional arithmetic operations. In experiments, RPCholesky matches or improves on the performance of alternative algorithms for low-rank psd approximation. Moreover, RPCholesky provably achieves near-optimal approximation guarantees. The simplicity, effectiveness, and robustness of this algorithm strongly support its use for large-scale kernel computations.<br />
<br />
Joint work with Yifan Chen, Ethan Epperly, and Rob Webber. Available at arXiv:2207.06503.<br />
<br />
==November 18, 2022, Friday at 4pm [http://homepages.math.uic.edu/~freitag/index.html Jim Freitag] (U of Illinois-Chicago) Zoom link: https://go.wisc.edu/jimfreitag<nowiki/>==<br />
'''Now available:''' [https://people.math.wisc.edu/logic/talks/221118-Freitag.mp4 Recording] and [https://people.math.wisc.edu/logic/talks/221118-Freitag.pdf Slides]<br />
<br />
(hosts: Lempp, Andrews)<br />
<br />
'''When any three solutions are independent'''<br />
<br />
In this talk, we'll talk about a surprising recent result about the algebraic relations between solutions of a differential equation. The result has applications to functional transcendence, diophantine geometry, and compact complex manifolds.<br />
<br />
==November 21, 2022, <span style="color: red;">Monday</span> at 4pm [https://math.mit.edu/directory/profile.html?pid=1698 Andrei Negut] (MIT) Zoom link: [https://go.wisc.edu/andreinegut https://go.wisc.edu/andreinegut]==<br />
Hiring talk.<br />
<br />
(hosts: Arinkin, Caldararu)<br />
<br />
'''From gauge theory to geometric representation theory and back'''<br />
<br />
We start from the celebrated construction (due to Grojnowski and Nakajima) of a Heisenberg algebra action on the cohomology groups of Hilbert schemes of points on surfaces<br />
<br />
# replacing Hilbert schemes with moduli spaces of higher rank sheaves yields a computation of Nekrasov partition functions in 5d supersymmetric gauge theory, and a proof of the deformed Alday-Gaiotto-Tachikawa conjecture.<br />
# replacing cohomology by Chow groups gives a proof of the Beauville conjecture in the hyperkahler geometry of Hilbert schemes of points on K3 surfaces (with Maulik)<br />
# working with derived categories allows us to construct a detailed framework realizing categorical knot invariants in terms of the geometry of Hilbert schemes of points on the affine plane (with Gorsky and Rasmussen)<br />
<br />
==December 2, 2022, Friday at 4pm [TBD]==<br />
<blockquote>'''Fractal Geometry of the KPZ equation'''<br />
<br />
''Abstract:'' The Kardar-Parisi-Zhang (KPZ) equation is a fundamental stochastic PDE related to many important models like random growth processes, Burgers turbulence, interacting particles system, random polymers etc. In this talk, we focus on how the tall peaks and deep valleys of the KPZ height function grow as time increases. In particular, we will ask what is the appropriate scaling of the peaks and valleys of the (1+1)-d KPZ equation and whether they converge to any limit under those scaling. These questions will be answered via the law of iterated logarithms and fractal dimensions of the level sets. The talk will be based on joint works with Sayan Das and Jaeyun Yi. If time permits, I will also mention an interesting story about the (2+1)-d and (3+1)-d case (work in progress with Jaeyun Yi).</blockquote><br />
<br />
==December 9, 2022, Friday at 4pm [TBD]==<br />
(reserved by HC. contact: Stechmann)<br />
== Future Colloquia ==<br />
<br />
[[Colloquia/Fall2022|Fall 2022]]<br />
<br />
[[Colloquia/Spring2023|Spring 2023]]<br />
<br />
== Past Colloquia ==<br />
[[Spring 2022 Colloquiums|Spring 2022]]<br />
<br />
[[Colloquia/Fall2021|Fall 2021]]<br />
<br />
[[Colloquia/Spring2021|Spring 2021]]<br />
<br />
[[Colloquia/Fall2020|Fall 2020]]<br />
<br />
[[Colloquia/Spring2020|Spring 2020]]<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]<br />
<br />
[[WIMAW]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Applied_and_Computational_Mathematics&diff=24027Applied and Computational Mathematics2022-11-10T15:25:54Z<p>Nagreen: </p>
<hr />
<div><br />
[[Image:jet.jpg|link=http://www.math.wisc.edu/~jeanluc|frame|Jet striking an inclined plane.]]<br />
<br />
[[Image:HMSS2013_highlight1.png|link=http://dx.doi.org/10.1017/jfm.2012.597|frame]]<br />
[[Image:HMSS2013_highlight2.png|link=http://www.math.wisc.edu/~stechmann/research/|frame|Scattered rain clouds versus an organized storm (a squall line).]] <!-- Added by stechmann 2013-02-03 --><br />
<br />
= '''Applied and Computational Mathematics at UW-Madison''' =<br />
<br />
Welcome to the Applied and Computational Mathematics Group at the University of Wisconsin, Madison. Our faculty members, postdoctoral fellows, and students are involved in a variety of research projects, including fluid dynamics, partial and stochastic differential equations, scientific computing, biology, biochemistry, topology, and data science.<br />
<br />
To pursue graduate studies in Applied and Computational Mathematics, see the [https://math.wisc.edu/graduate/ Mathematics Graduate Program].<br />
<br />
__TOC__<br />
<br />
== News and opportunities ==<br />
<br />
Full a full list of recent events within the department, see the [https://math.wisc.edu/ Mathematics Department Website].<br />
<br />
* '''Tom Edwards''' (former Ph.D. student of Leslie Smith and Sam Stechmann) will begin a new job at Google in Fall 2021. <!-- Updated by sam 2021-11-09 --><br />
<br />
* '''Quanling Deng''' (former postdoc of Sam Stechmann and Nan Chen) has accepted a faculty position at the Australian National University to begin in January 2022. <!-- Updated by sam 2021-11-09 --><br />
<br />
* '''Ying Li''' (former Ph.D. student of Sam Stechmann) will begin as a Data Scientist at Wells Fargo Bank in November 2021. <!-- Updated by sam 2021-11-09 --><br />
<br />
* '''Leonardo Andrés Zepeda-Núñez''' has joined the department (Fall 2019). <!-- Updated by Saverio 2019-07-19 --><br />
<br />
* '''Amy Cochran''' has joined the department (Fall 2019). <!-- Updated by saverio 2019-07-19 --><br />
<br />
* '''Jason Torchinsky''' (Ph.D. student of Sam Stechmann) has been awarded a Computational Science Graduate Fellowship from the Department of Energy (Spring 2019). <!-- Added by stechmann 2019-07-21 --><br />
<br />
* '''Nan Chen''' has joined the department (Fall 2018). <!-- Updated by saverio 2019-07-19 --><br />
<br />
* '''Will Mitchell''' (former Ph.D. student of Saverio Spagnolie) has accepted a faculty position at Macalester College to begin in Fall 2019. <!-- Updated by saverio 2019-03-18 --><br />
<br />
* '''Lei Li''' (former Ph.D. student of Saverio Spagnolie) has accepted a faculty position at Shanghai Jiao Tong University to begin in Fall 2018. <!-- Updated by saverio 2019-03-18 --><br />
<br />
* '''Jean-Luc Thiffeault''' was featured in [https://www.washingtonpost.com/news/wonk/wp/2016/08/19/the-secret-mesmerizing-math-of-taffy-pulling/ Washington Post's Wonkblog] on his paper exploring the mathematical history of taffy pullers. [http://arxiv.org/pdf/1608.00152v1.pdf link to paper] <!-- Added by saverio 2016-09-16 --><br />
<br />
* '''Gheorghe Craciun''' was featured in [https://sinews.siam.org/DetailsPage/tabid/900/ArtMID/2243/ArticleID/781/Default.aspx SIAM News] on his recent proof of the Global Attractor Conjecture. [http://arxiv.org/pdf/1501.02860.pdf link to paper] <!-- Added by saverio 2016-09-16 --><br />
<br />
<!-- * '''Scott Hottovy''' (former postdoc of Sam Stechmann) has accepted a faculty position at the US Naval Academy to begin in Fall 2016. --> <!-- Added by stechmann 2019-07-21 --><br />
<br />
<!-- * '''Reed Ogrosky''' (former postdoc of Sam Stechmann) has accepted a faculty position at Virginia Commonwealth University to begin in Fall 2016. --> <!-- Added by stechmann 2019-07-21 --><br />
<br />
<!-- * '''Lei Li''' (Ph.D. student of Saverio Spagnolie) has accepted a postdoc offer from Duke University and will begin in Fall 2014. <!-- Added by saverio 2015-03-17 --><br />
<br />
<!-- * '''Gheorghe Craciun''' has received a [http://grad.wisc.edu/vilaswinners2013 Vilas Associate Award]! --> <!-- Added by jeanluc 2014-02-19 --><br />
<br />
<!-- * '''Sam Stechmann''' has been awarded a [http://www.sloan.org/sloan-research-fellowships/2014-sloan-research-fellows/ Sloan Fellowship]! --> <!-- Added by jeanluc 2014-02-19 --><br />
<br />
<!-- * '''Zhennan Zhou''' (Ph.D. student of Shi Jin) has accepted a postdoc offer from Duke University and will begin in Fall 2014. --> <!-- Added by jeanluc 2014-02-14 --><br />
<br />
<!-- * '''Jingwei Hu''' (former Ph.D. student of Shi Jin, currently a postdoc at Texas-Austin) has accepted a tenure-track assistant professor position at Purdue University and will begin in Fall 2014. --> <!-- Added by jeanluc 2014-02-14 --><br />
<br />
<!-- * '''Masanori Koyama''' (Ph.D. student of David Anderson) graduated in Fall 2014. He began a postdoc at the Department of Systems Science, Kyoto University starting in January 2014. --> <!-- Added by Anderson 2014-02-10 --><br />
<br />
<!-- * '''Leland Jefferis''' (Ph.D. student of Shi Jin) was awarded an NSF Postdoctoral Fellowship and will be a postdoc at Department of Mathematics, Stanford University starting in Fall 2014. --> <!-- Added by jeanluc 2014-02-01 --><br />
<br />
<!-- * '''Shi Jin''' was elected to [http://fellows.siam.org/index.php?sort=year&value=2013 SIAM Fellow]. Last year he was part of the inaugural class of [http://www.ams.org/profession/fellows-list AMS Fellows]. --> <!-- Added by jeanluc 2013-06-11 --><br />
<br />
== Workshops ==<br />
<br />
* [https://indico.flatironinstitute.org/event/30/ Mathematical Fluids, Materials & Biology] Ann Arbor, MI, June 12-15, 2019<br />
* [http://www.math.wisc.edu/apamrtg/?q=meetings/rtgseminars/turbulence RTG Workshop: Turbulent and Coherent Convection] 224 Ingraham Hall, May 27-29, 2015<br />
<br />
== Seminars ==<br />
<br />
''Organized by Applied Math''<br />
<br />
* [http://www.math.wisc.edu/wiki/index.php/Applied/ACMS Applied and Computational Math Seminar] (Fridays at 2:25pm, VV 901)<br />
* [http://www.math.wisc.edu/wiki/index.php/Applied/GPS Graduate Applied Math Seminar] (Mondays at 3:40pm, VV 901)<br />
* [http://www.math.wisc.edu/wiki/index.php/Applied/Physical_Applied_Math Physical Applied Math] Group Meeting (Spagnolie/Thiffeault) (Thursdays at 4:00pm, VV 901)<br />
* [http://www.math.wisc.edu/wiki/index.php/Networks_Seminar Networks Seminar] (Anderson/Johnston/Craciun) (Wednesdays at 2:25pm, VV 901)<br />
<!-- * Joint Math/Atmospheric & Oceanic Sciences Informal Seminar (Thursdays at 3:45 pm, AOS 811) --><br />
<br />
<br />
''Other seminar series of interest''<br />
<br />
* [http://www.math.wisc.edu/wiki/index.php/Colloquia Mathematics Colloquium] (Fridays at 4:00pm, VV B239)<br />
* [http://www.math.wisc.edu/wiki/index.php/Probability_Seminar Probability Seminar] (Thursdays at 2:25pm, VV 901)<br />
* [http://silo.ece.wisc.edu/web/content/seminars SILO Seminar] (Wednesdays at 12:30pm, 3rd floor WID)<br />
<!-- * [http://wid.wisc.edu/research/optimization/seminars/wid-dow/ WID-DOW Seminar] (Mondays at 4:00pm, 3rd floor WID) --><br />
* [http://sprott.physics.wisc.edu/Chaos-Complexity/ Chaos and Complex Systems Seminar] (Tuesdays at 12:05pm, 4274 Chamberlin Hall)<br />
* [http://www.physics.wisc.edu/twap/view.php?name=PDC Physics Department Colloquium] (Fridays at 3:30 pm; 2241 Chamberlin Hall)<br />
* [http://today.wisc.edu/events/search?utf8=%E2%9C%93&search%5Bterm%5D=aos+colloquium AOS Colloquium] (Mondays at 3:30 pm; 811 AOSS building)<br />
* [http://www.astro.wisc.edu/news-events/events/category/1/1 Astronomy Colloquium] (Thursdays at 3:45 pm; 4421 Sterling Hall)<br />
<br><br />
<br />
== Tenured and tenure-track faculty ==<br />
<br />
[http://www.math.wisc.edu/~anderson/ David Anderson:] (Duke, 2005) probability and stochastic processes, computational methods for stochastic processes, biochemical networks, mathematical/systems biology.<br />
<br />
[http://www.math.wisc.edu/~angenent/ Sigurd Angenent:] (Leiden, 1986) partial differential equations.<br />
<br />
[https://www.math.wisc.edu/~chennan/ Nan Chen:] (Courant, 2016) uncertainty quantification, data assimilation, geophysics, stochastic modeling, and data science.<br />
<br />
[https://sites.google.com/site/amylouisecochran/home Amy Cochran:] (Cornell, 2013) population health science, computational psychiatry.<br />
<br />
[https://sites.google.com/site/albertodelpia/ Alberto Del Pia]: (Padova, 2009) mathematical optimization, discrete optimization, data science, theoretical computer science<br />
<br />
[http://www.math.wisc.edu/~craciun/ Gheorghe Craciun:] (Ohio State, 2002) mathematical biology, biochemical networks, biological interaction networks.<br />
<br />
[http://www.math.wisc.edu/~shamgar/ Shamgar Gurevich:] (Tel Aviv, 2006) Representation theory of groups, algebraic geometry, applications to signal Processing, structural biology, mathematical physics.<br />
<br />
[http://www.math.wisc.edu/~qinli/ Qin Li:] (Wisconsin, 2012) applied & computational mathematics.<br />
<br />
[https://hanbaeklyu.com/ Hanbaek Lyu] (Ohio State, 2018) discrete probability, dynamical systems, networks, optimization, machine learning<br />
<br />
[http://www.math.wisc.edu/~maribeff/ Gloria Mari-Beffa:] (Minnesota, 1991) differential geometry, applied math.<br />
<br />
[http://www.math.wisc.edu/~roch/ S&eacute;bastien Roch:] (Berkeley, 2007) applied probability, statistics and theoretical computer science, with emphasis on biological applications.<br />
<br />
[http://www.math.wisc.edu/~lsmith/ Leslie Smith:] (MIT, 1988) applied mathematics. Waves and coherent structures in oceanic and atmospheric flows. <br />
<br />
[http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie:] (Courant, 2008) fluid dynamics, biological locomotion, soft matter, computational mathematics.<br />
<br />
[http://www.math.wisc.edu/~stechmann/ Sam Stechmann:] (Courant, 2008) applied math, stochastic modeling, fluid dynamics, atmospheric science, computational mathematics.<br />
<br />
[http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault:] (Texas, 1998) fluid dynamics, mixing, biological swimming and mixing, topological dynamics.<br />
<br />
[http://www.math.wisc.edu/~waleffe/ Fabian Waleffe:] (MIT, 1989) applied and computational mathematics. Fluid dynamics, hydrodynamic instabilities. Turbulence and unstable coherent flows.<br />
<br />
[http://math.mit.edu/~lzepeda/ Leonardo Andrés Zepeda-Núñez:] (MIT, 2015) machine learning, numerical analysis, wave propagation, inverse problems.<br />
<br />
<br />
<br />
<!-- [http://www.math.wisc.edu/~kiselev/ Alex (Sasha) Kiselev:] (CalTech, 1997) partial differential equations, Fourier analysis and applications in fluid mechanics, combustion, mathematical biology and Schr&ouml;dinger operators.--><br />
<!-- [http://www.math.wisc.edu/~zlatos/ Andrej Zlatos:] (Caltech, 2003) partial differential equations, combustion, fluid dynamics, Schrödinger operators, orthogonal polynomials--><br />
<!-- [http://www.math.wisc.edu/~jin/ Shi Jin:] (Arizona, 1991) applied & computational mathematics. --><br />
<!-- [http://www.math.wisc.edu/~mitchell/ Julie Mitchell:] (Berkeley, 1998) computational mathematics, structural biology. --><br><br />
<br />
== Postdoctoral fellows and researchers ==<br />
<br />
[http://vv811a.math.wisc.edu/persepolis/index.php/members/10-members/30-majid-arabgol Majid Arabgol:]<br />
HPC & Visualization Research Scholar<br />
<br />
[http://www.math.wisc.edu/~boonkasa Anakewit (Tete) Boonkasame:] (UW Madison, 2012)<br />
<br />
[http://mbudisic.wordpress.com Marko Budi&#x161;i&#x107;:] (UC Santa Barbara, 2012) dynamical systems<br />
<br />
[http://www.math.wisc.edu/~caiy Yongyong Cai:] (National University of Singapore, 2012)<br />
<br />
[https://artioevans.wordpress.com/ Arthur Evans:] (UCSD, 2011) soft matter, complex fluids<br />
<br />
[https://www.math.wisc.edu/~pgera/ Prerna Gera:] (Buffalo, 2018) fluid-structure interactions<br />
<br />
[https://people.math.wisc.edu/~tgchandler/ Thomas Chandler:] (Oxford, 2021) soft matter, complex fluids<br />
<br />
[http://www.math.wisc.edu/~mjohnston3 Matthew Johnston:] (University of Waterloo, 2011) dynamical systems<br />
<br />
<!-- [http://www.math.wisc.edu/~dwei/ Dongming Wei:] (Maryland, 2007) nonlinear partial differential equations, applied analysis, and numerical computation. --><br />
<br />
<br><br />
<br />
== Current graduate students ==<br />
<br />
{| class="wikitable sortable" style="margin-left: auto; margin-right: auto; border: none;"<br />
|+ List of current graduate students (updated summer of 2021).<br />
|-<br />
! Student !! Advisor (1) !! Advisor (2) !! Program Start Year !! Research Area<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Zinan Wang] || Sigurd Angenent || || || <br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Jeffrey Covington] || Nan Chen || || 2018 || <br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Xiao Hou] || Nan Chen || Qin Li || || <br />
|-<br />
| [https://sites.google.com/wisc.edu/yingdali Yingda Li] || Nan Chen || || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Yuchen Li] || Nan Chen || || ||<br />
|-<br />
|Sanchita Chakraborty<br />
|Nan Chen<br />
|<br />
|2022<br />
|<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Haley Colgate] || Amy Cochran || || 2020 ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Enkhzaya "Eza" Enkhtaivan] || Amy Cochran || || ||<br />
|-<br />
| [https://sites.google.com/view/jiaxinjin/ Jiaxin Jin] || Gheorghe Craciun || Chanwoo Kim || ||<br />
|-<br />
| [https://sites.google.com/site/mathjennyy/ Jenny Yeon] || Gheorghe Craciun || || ||<br />
|-<br />
| [https://sites.google.com/view/pollyyu Polly Yu] || Gheorghe Craciun || || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Hongxu Chen] || Chanwoo Kim || Qin Li || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Shi Chen] || Qin Li || || ||<br />
|-<br />
| [https://people.math.wisc.edu/~zding49/ Zhiyan Ding] || Qin Li || || ||<br />
|-<br />
| [https://sites.google.com/wisc.edu/nair-anjali/home Anjali Nair] || Qin Li || || 2018 ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Jenny Wei] || Qin Li || Yingyu Liang || ||<br />
|-<br />
| [https://borongzhang.com/ Borong Zhang] || Qin Li || Leonardo Zepeda-Núñez || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Parvathi Madathil Kooloth] || Leslie Smith || || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Varun Gudibanda] || Leslie Smith || || 2020 ||<br />
|-<br />
| [https://www.physics.wisc.edu/directory/lough-wilson-bennett/ Wilson Lough] || Saverio Spagnolie || || 2018 ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Tianhong Huang] || Samuel Stechmann || || ||<br />
|-<br />
| [https://jasonltorchinsky.github.io/ Jason Torchinsky] || Samuel Stechmann || || 2018 || Data assimilation, multi-model communication, atmospheric modelling<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Carrie Hongfei Chen] || Jean-Luc Thiffeault || || ||<br />
|-<br />
| [https://sites.google.com/wisc.edu/yufeng-webpage/home Yu Feng] || Jean-Luc Thiffeault || || ||<br />
|-<br />
| [https://www.math.wisc.edu/~boakley/ Bryan Oakley] || Jean-Luc Thiffeault || || ||<br />
|}<br />
<br />
<br />
<br />
<!-- Past students: --><br />
<!-- [https://math.wisc.edu/graduate-students/ Liu Liu:] Student of Shi Jin. --><br />
<!-- Yun Sun: Student of David Anderson.--><br />
<!-- [http://www.math.wisc.edu/~zhou/ Zhennan Zhou:] Student of Shi Jin.--><br />
<!-- [http://www.math.wisc.edu/~mueller/ Peter Mueller:] Student of Jean-Luc Thiffeault.--><br />
<!-- [http://www.math.wisc.edu/~jefferis/ Leland Jefferis:] Student of Shi Jin. --><br />
<!-- [http://www.math.wisc.edu/~hu/ Jingwei Hu:] Student of Shi Jin. --><br />
<!-- [http://www.math.wisc.edu/~yan/ Bokai Yan:] Student of Shi Jin. --><br />
<!-- [http://www.math.wisc.edu/~crompton/ Bryan Crompton:] Student of Saverio Spagnolie. --><br />
<!-- [http://www.math.wisc.edu/~whmitchell/ Will Mitchell:] Student of Saverio Spagnolie. --><br />
<!--Zhan Wang: Student of Paul Milewski.--><br />
<!--Anekewit (Tete) Boonkasame: Student of Paul Milewski.--><br />
<!--Peng Qi: Student of Shi Jin. --><br />
<!--Li (Aug) Wang: Student of Shi Jin. --><br />
<!-- Lei Li: Student of Saverio Spagnolie. --><br />
<!--Li Wang: Student of Leslie Smith. --><br />
<!--David Seal: Student of James Rossmanith. --><br />
<!--E. Alec Johnson: Student of James Rossmanith. --><br />
<!--Hesam Dashti: MSc Student of Amir Assadi.--><br />
<!--Qiang Deng: Student of Leslie Smith.--><br />
<!--[http://www.math.wisc.edu/~matz/ Sarah Tumasz:] Student of Jean-Luc Thiffeault.--><br />
<!--[http://www.math.wisc.edu/~qinli/ Qin Li:] Student of Shi Jin.--><br />
<!--Yongtao Cheng: Student of James Rossmanith.--><br />
<!-- [http://www.math.wisc.edu/~mueller/ Peter Mueller:] Student of Jean-Luc Thiffeault. --><br />
<br />
<br><br />
<br />
== Graduate course offerings ==<br />
<br />
=== Fall 2022 ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (David Keating, Erik Bates)<br />
* Math 703: Methods of Applied Mathematics I (Gheorghe Craciun)<br />
* Math 714: Methods of Computational Math I (Sam Stechmann)<br />
* Math 717: Stochastic Computational Methods (Nan Chen)<br />
<br />
=== Spring 2023 ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (David Keating, Sebastien Roch)<br />
* Math 704: Methods of Applied Mathematics II (Jean-Luc Thiffeault)<br />
* Math 715: Methods of Computational Math II (Maurice Fabien)<br />
* Math 801: Topics in Applied Mathematics: Computational Fluid Dynamics (Saverio Spagnolie)<br />
<br />
<br />
<!--=== [http://www.math.wisc.edu/graduate/gcourses_fall Spring 2021] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (Scott Smith, Erik Bates, Tetiana Shcherbyna)<br />
* Math 704: Methods of Applied Mathematics II (Jean-Luc Thiffeault)<br />
* Math 705: Mathematical Fluid Dynamics (Leslie Smith)<br />
* Math 715: Methods of Computational Math II (Leonardo Andrés Zepeda-Núñez)<br />
* Math 716: Ordinary Differential Equations (Sigurd Angenent)<br />
* Math 801: Topics in Applied Mathematics (Gheorghe Craciun)<br />
* Math 807: Dynamical Systems (Hung Tran)<br />
* Math 820: Partial Differential Equations (Chanwoo Kim)<br />
<br />
<!--=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2021] ===<br />
<br />
* Math 623: Complex Analysis (Betsy Stovall)<br />
* Math 627: Introduction to Fourier Analysis (Sergey Denisov)<br />
* Math 632: Introduction to Stochastic Processes (Vadim Gorin, Benedek Valko)<br />
* Math 703: Methods of Applied Mathematics I (Gheorghe Craciun)<br />
* Math 714: Methods of Computational Math I (Leonardo Andrés Zepeda-Núñez)<br />
* Math 821: Advanced Topics in Real Analysis [Fluid Dynamics] (Mihaela Ifrim)<br />
* Math 833: Topics in the Theory of Probability [Stochastic Computational Methods] (Nan Chen)<br />
<br />
<br />
<!--=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2019] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (David Anderson, Timo Seppalainen, Benedek Valko)<br />
* Math 703: Methods of Applied Mathematics I (Saverio Spagnolie)<br />
* Math 705: Mathematical Fluid Dynamics (Leslie Smith)<br />
* Math 714: Methods of Computational Math I (Sam Stechmann)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2020] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (TBA)<br />
* Math 704: Methods of Applied Mathematics II (TBA)<br />
* Math 715: Methods of Computational Math II (TBA)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2016] ===<br />
<br />
* Math 606: Mathematical Methods for Structural Biology (Julie Mitchell)<br />
* Math 632: Introduction to Stochastic Processes (Sebastien Roch)<br />
* Math 703: Methods of Applied Mathematics I (Gheorghe Craciun)<br />
* Math 714: Methods of Computational Math I (Shi Jin)<br />
* Math 801: Topics in Applied Mathematics: Hydrodynamic instabilities and bifurcations (Fabian Waleffe)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2017] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (Daniele Cappelletti, Jun Yin)<br />
* Math 704: Methods of Applied Mathematics II (Jean-Luc Thiffeault)<br />
* Math 715: Methods of Computational Math II (Qin Li)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2014] ===<br />
<br />
* Math 606: Mathematical Methods for Structural Biology (Julie Mitchell)<br />
* Math 632: Introduction to Stochastic Processes (Sebastien Roch, Benedek Valko)<br />
* Math 703: Methods of Applied Mathematics I (Gheorghe Craciun)<br />
* Math 714: Methods of Computational Math I (Sam Stechmann)<br />
* Math 801: Topics in Applied Mathematics (Shi Jin)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2015] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (Sebastien Roch, Jun Yin)<br />
* Math 704: Methods of Applied Mathematics II (Sam Stechmann)<br />
* Math 715: Methods of Computational Math II (Saverio Spagnolie)<br />
* Math 801: Topics in Applied Mathematics: Nonlinear dynamics and applications (Gheorghe Craciun) --><br />
<br />
<!-- === [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2013] ===<br />
<br />
* Math 605: Stochastic Methods for Biology (David Anderson)<br />
* Math 632: Introduction to Stochastic Processes (Gregory Shinault)<br />
* Math 703: Methods of Applied Mathematics 1 (Jean-Luc Thiffeault)<br />
* Math 714: Methods of Computational Math I (Shi Jin)<br />
* Math 826: Advanced Topics in Functional Analysis and Differential Equations (Alexander Kiselev)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2014] ===<br />
<br />
<br />
* Math 609: Mathematical Methods for Systems Biology (Gheorghe Craciun)<br />
* Math 632: Introduction to Stochastic Processes (Gregory Shinault)<br />
* Math 704: Methods of Applied Mathematics II (Sam Stechmann)<br />
* Math 715: Methods of Computational Math II (Jean-Luc Thiffeault)<br />
* Math 801: Topics in Applied Mathematics: Biological Continuum Mechanics (Saverio Spagnolie) --><br />
<br />
<br />
<!-- === [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2012] ===<br />
<br />
* Math 606: Mathematical Methods for Structural Biology (Julie Mitchell)<br />
* Math 632: Introduction to Stochastic Processes (David Anderson)<br />
* Math 703: Methods of Applied Mathematics 1 (Jean-Luc Thiffeault)<br />
* Math 705: Mathematical Fluid Dynamics (Saverio Spagnolie)<br />
* Math 714: Methods of Computational Math I (Shi Jin)<br />
* Math 833: Topics in Probability - Stochastic Processes in Evolution and Genetics (Sebastien Roch)<br />
* Math 842: Topics in Applied Algebra for EE/Math/CS students (Shamgar Gurevich)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2013] ===<br />
<br />
* Math 704: Methods of Applied Mathematics 2 (Sam Stechmann)<br />
* Math 715: Methods of Computational Math II (Saverio Spagnolie)<br />
* Math 801: Topics in Applied Mathematics -- Mathematical Aspects of Mixing (Jean-Luc Thiffeault) --><br />
<br />
<!-- === Spring 2012 ===<br />
* Math 714: [http://www.math.wisc.edu/math-714-scientific-computing Methods of Computational Math I] (S. Stechmann) --><br />
<br />
<br />
<!--<br />
=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2011] ===<br />
<br />
* Math 605: [http://www.math.wisc.edu/math-727-calculus-variations-0 Stochastic Methods for Biology] (D. Anderson)<br />
* Math 703: [http://www.math.wisc.edu/math-703-methods-applied-mathematics-i Methods of Applied Mathematics II] (L. Smith)<br />
* Math 707: [http://www.math.wisc.edu/math707-ema700-theory-elasticity Theory of Elasticity] (F. Waleffe)<br />
* Math 714: [http://www.math.wisc.edu/math-714-scientific-computing Methods of Computational Math I] (J. Mitchell)<br />
* Math 801: [http://www.math.wisc.edu/801-waves-fluids Comp Math Applied to Biology] (A. Assadi)<br />
* Math 837: [http://www.math.wisc.edu/math-837-topics-numerical-analysis Topics in Numerical Analysis] (S. Jin)<br />
--><br />
<br />
<!--<br />
Spring 2011:<br />
* Math 609: [https://www.math.wisc.edu/609-mathematical-methods-systems-biology Mathematical Methods for Systems Biology] (G. Craciun)<br />
* Math 704: [https://www.math.wisc.edu/704-methods-applied-mathematics-2 Methods of Applied Mathematics II] (S. Stechmann)<br />
* Math/CS 715: [https://www.math.wisc.edu/715-methods-computational-math-ii Methods of Computational Math II] (S. Jin)<br />
* Math 801: [https://www.math.wisc.edu/math-801-hydrodynamic-instabilities-chaos-and-turbulence Hydrodynamic Instabilities, Chaos and Turbulence] (F. Waleffe)<br />
* Math 826: [https://www.math.wisc.edu/826-Functional-Analysis Partial Differential Equations in Fluids and Biology] (A. Kiselev)<br />
* Math/CS 837: [https://www.math.wisc.edu/837-Numerical-Analysis Numerical Methods for Hyperbolic PDEs] (J. Rossmanith)<br />
--><br />
<br />
<br><br />
<br />
----<br />
<br />
<br />
[http://www3.clustrmaps.com/stats/maps-no_clusters/www.math.wisc.edu-wiki-index.php-Applied-thumb.jpg Locations of visitors to this page] ([http://www3.clustrmaps.com/user/195f39ef Clustermaps])</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Applied_and_Computational_Mathematics&diff=24026Applied and Computational Mathematics2022-11-10T15:24:45Z<p>Nagreen: /* Tenured and tenure-track faculty */ added Alberto Del Pia.</p>
<hr />
<div><br />
[[Image:jet.jpg|link=http://www.math.wisc.edu/~jeanluc|frame|Jet striking an inclined plane.]]<br />
<br />
[[Image:HMSS2013_highlight1.png|link=http://dx.doi.org/10.1017/jfm.2012.597|frame]]<br />
[[Image:HMSS2013_highlight2.png|link=http://www.math.wisc.edu/~stechmann/research/|frame|Scattered rain clouds versus an organized storm (a squall line).]] <!-- Added by stechmann 2013-02-03 --><br />
<br />
= '''Applied and Computational Mathematics at UW-Madison''' =<br />
<br />
Welcome to the Applied and Computational Mathematics Group at the University of Wisconsin, Madison. Our faculty members, postdoctoral fellows, and students are involved in a variety of research projects, including fluid dynamics, partial and stochastic differential equations, scientific computing, biology, biochemistry, topology, and data science.<br />
<br />
To pursue graduate studies in Applied and Computational Mathematics, see the [https://math.wisc.edu/graduate/ Mathematics Graduate Program].<br />
<br />
__TOC__<br />
<br />
== News and opportunities ==<br />
<br />
Full a full list of recent events within the department, see the [https://math.wisc.edu/ Mathematics Department Website].<br />
<br />
* '''Tom Edwards''' (former Ph.D. student of Leslie Smith and Sam Stechmann) will begin a new job at Google in Fall 2021. <!-- Updated by sam 2021-11-09 --><br />
<br />
* '''Quanling Deng''' (former postdoc of Sam Stechmann and Nan Chen) has accepted a faculty position at the Australian National University to begin in January 2022. <!-- Updated by sam 2021-11-09 --><br />
<br />
* '''Ying Li''' (former Ph.D. student of Sam Stechmann) will begin as a Data Scientist at Wells Fargo Bank in November 2021. <!-- Updated by sam 2021-11-09 --><br />
<br />
* '''Leonardo Andrés Zepeda-Núñez''' has joined the department (Fall 2019). <!-- Updated by Saverio 2019-07-19 --><br />
<br />
* '''Amy Cochran''' has joined the department (Fall 2019). <!-- Updated by saverio 2019-07-19 --><br />
<br />
* '''Jason Torchinsky''' (Ph.D. student of Sam Stechmann) has been awarded a Computational Science Graduate Fellowship from the Department of Energy (Spring 2019). <!-- Added by stechmann 2019-07-21 --><br />
<br />
* '''Nan Chen''' has joined the department (Fall 2018). <!-- Updated by saverio 2019-07-19 --><br />
<br />
* '''Will Mitchell''' (former Ph.D. student of Saverio Spagnolie) has accepted a faculty position at Macalester College to begin in Fall 2019. <!-- Updated by saverio 2019-03-18 --><br />
<br />
* '''Lei Li''' (former Ph.D. student of Saverio Spagnolie) has accepted a faculty position at Shanghai Jiao Tong University to begin in Fall 2018. <!-- Updated by saverio 2019-03-18 --><br />
<br />
* '''Jean-Luc Thiffeault''' was featured in [https://www.washingtonpost.com/news/wonk/wp/2016/08/19/the-secret-mesmerizing-math-of-taffy-pulling/ Washington Post's Wonkblog] on his paper exploring the mathematical history of taffy pullers. [http://arxiv.org/pdf/1608.00152v1.pdf link to paper] <!-- Added by saverio 2016-09-16 --><br />
<br />
* '''Gheorghe Craciun''' was featured in [https://sinews.siam.org/DetailsPage/tabid/900/ArtMID/2243/ArticleID/781/Default.aspx SIAM News] on his recent proof of the Global Attractor Conjecture. [http://arxiv.org/pdf/1501.02860.pdf link to paper] <!-- Added by saverio 2016-09-16 --><br />
<br />
<!-- * '''Scott Hottovy''' (former postdoc of Sam Stechmann) has accepted a faculty position at the US Naval Academy to begin in Fall 2016. --> <!-- Added by stechmann 2019-07-21 --><br />
<br />
<!-- * '''Reed Ogrosky''' (former postdoc of Sam Stechmann) has accepted a faculty position at Virginia Commonwealth University to begin in Fall 2016. --> <!-- Added by stechmann 2019-07-21 --><br />
<br />
<!-- * '''Lei Li''' (Ph.D. student of Saverio Spagnolie) has accepted a postdoc offer from Duke University and will begin in Fall 2014. <!-- Added by saverio 2015-03-17 --><br />
<br />
<!-- * '''Gheorghe Craciun''' has received a [http://grad.wisc.edu/vilaswinners2013 Vilas Associate Award]! --> <!-- Added by jeanluc 2014-02-19 --><br />
<br />
<!-- * '''Sam Stechmann''' has been awarded a [http://www.sloan.org/sloan-research-fellowships/2014-sloan-research-fellows/ Sloan Fellowship]! --> <!-- Added by jeanluc 2014-02-19 --><br />
<br />
<!-- * '''Zhennan Zhou''' (Ph.D. student of Shi Jin) has accepted a postdoc offer from Duke University and will begin in Fall 2014. --> <!-- Added by jeanluc 2014-02-14 --><br />
<br />
<!-- * '''Jingwei Hu''' (former Ph.D. student of Shi Jin, currently a postdoc at Texas-Austin) has accepted a tenure-track assistant professor position at Purdue University and will begin in Fall 2014. --> <!-- Added by jeanluc 2014-02-14 --><br />
<br />
<!-- * '''Masanori Koyama''' (Ph.D. student of David Anderson) graduated in Fall 2014. He began a postdoc at the Department of Systems Science, Kyoto University starting in January 2014. --> <!-- Added by Anderson 2014-02-10 --><br />
<br />
<!-- * '''Leland Jefferis''' (Ph.D. student of Shi Jin) was awarded an NSF Postdoctoral Fellowship and will be a postdoc at Department of Mathematics, Stanford University starting in Fall 2014. --> <!-- Added by jeanluc 2014-02-01 --><br />
<br />
<!-- * '''Shi Jin''' was elected to [http://fellows.siam.org/index.php?sort=year&value=2013 SIAM Fellow]. Last year he was part of the inaugural class of [http://www.ams.org/profession/fellows-list AMS Fellows]. --> <!-- Added by jeanluc 2013-06-11 --><br />
<br />
== Workshops ==<br />
<br />
* [https://indico.flatironinstitute.org/event/30/ Mathematical Fluids, Materials & Biology] Ann Arbor, MI, June 12-15, 2019<br />
* [http://www.math.wisc.edu/apamrtg/?q=meetings/rtgseminars/turbulence RTG Workshop: Turbulent and Coherent Convection] 224 Ingraham Hall, May 27-29, 2015<br />
<br />
== Seminars ==<br />
<br />
''Organized by Applied Math''<br />
<br />
* [http://www.math.wisc.edu/wiki/index.php/Applied/ACMS Applied and Computational Math Seminar] (Fridays at 2:25pm, VV 901)<br />
* [http://www.math.wisc.edu/wiki/index.php/Applied/GPS Graduate Applied Math Seminar] (Mondays at 3:40pm, VV 901)<br />
* [http://www.math.wisc.edu/wiki/index.php/Applied/Physical_Applied_Math Physical Applied Math] Group Meeting (Spagnolie/Thiffeault) (Thursdays at 4:00pm, VV 901)<br />
* [http://www.math.wisc.edu/wiki/index.php/Networks_Seminar Networks Seminar] (Anderson/Johnston/Craciun) (Wednesdays at 2:25pm, VV 901)<br />
<!-- * Joint Math/Atmospheric & Oceanic Sciences Informal Seminar (Thursdays at 3:45 pm, AOS 811) --><br />
<br />
<br />
''Other seminar series of interest''<br />
<br />
* [http://www.math.wisc.edu/wiki/index.php/Colloquia Mathematics Colloquium] (Fridays at 4:00pm, VV B239)<br />
* [http://www.math.wisc.edu/wiki/index.php/Probability_Seminar Probability Seminar] (Thursdays at 2:25pm, VV 901)<br />
* [http://silo.ece.wisc.edu/web/content/seminars SILO Seminar] (Wednesdays at 12:30pm, 3rd floor WID)<br />
<!-- * [http://wid.wisc.edu/research/optimization/seminars/wid-dow/ WID-DOW Seminar] (Mondays at 4:00pm, 3rd floor WID) --><br />
* [http://sprott.physics.wisc.edu/Chaos-Complexity/ Chaos and Complex Systems Seminar] (Tuesdays at 12:05pm, 4274 Chamberlin Hall)<br />
* [http://www.physics.wisc.edu/twap/view.php?name=PDC Physics Department Colloquium] (Fridays at 3:30 pm; 2241 Chamberlin Hall)<br />
* [http://today.wisc.edu/events/search?utf8=%E2%9C%93&search%5Bterm%5D=aos+colloquium AOS Colloquium] (Mondays at 3:30 pm; 811 AOSS building)<br />
* [http://www.astro.wisc.edu/news-events/events/category/1/1 Astronomy Colloquium] (Thursdays at 3:45 pm; 4421 Sterling Hall)<br />
<br><br />
<br />
== Tenured and tenure-track faculty ==<br />
<br />
[http://www.math.wisc.edu/~anderson/ David Anderson:] (Duke, 2005) probability and stochastic processes, computational methods for stochastic processes, biochemical networks, mathematical/systems biology.<br />
<br />
[http://www.math.wisc.edu/~angenent/ Sigurd Angenent:] (Leiden, 1986) partial differential equations.<br />
<br />
[https://www.math.wisc.edu/~chennan/ Nan Chen:] (Courant, 2016) uncertainty quantification, data assimilation, geophysics, stochastic modeling, and data science.<br />
<br />
[https://sites.google.com/site/amylouisecochran/home Amy Cochran:] (Cornell, 2013) population health science, computational psychiatry.<br />
<br />
[http://www.math.wisc.edu/~craciun/ Gheorghe Craciun:] (Ohio State, 2002) mathematical biology, biochemical networks, biological interaction networks.<br />
<br />
[http://www.math.wisc.edu/~shamgar/ Shamgar Gurevich:] (Tel Aviv, 2006) Representation theory of groups, algebraic geometry, applications to signal Processing, structural biology, mathematical physics.<br />
<br />
[http://www.math.wisc.edu/~qinli/ Qin Li:] (Wisconsin, 2012) applied & computational mathematics.<br />
<br />
[http://www.math.wisc.edu/~maribeff/ Gloria Mari-Beffa:] (Minnesota, 1991) differential geometry, applied math.<br />
<br />
[http://www.math.wisc.edu/~roch/ S&eacute;bastien Roch:] (Berkeley, 2007) applied probability, statistics and theoretical computer science, with emphasis on biological applications.<br />
<br />
[http://www.math.wisc.edu/~lsmith/ Leslie Smith:] (MIT, 1988) applied mathematics. Waves and coherent structures in oceanic and atmospheric flows. <br />
<br />
[http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie:] (Courant, 2008) fluid dynamics, biological locomotion, soft matter, computational mathematics.<br />
<br />
[http://www.math.wisc.edu/~stechmann/ Sam Stechmann:] (Courant, 2008) applied math, stochastic modeling, fluid dynamics, atmospheric science, computational mathematics.<br />
<br />
[http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault:] (Texas, 1998) fluid dynamics, mixing, biological swimming and mixing, topological dynamics.<br />
<br />
[http://www.math.wisc.edu/~waleffe/ Fabian Waleffe:] (MIT, 1989) applied and computational mathematics. Fluid dynamics, hydrodynamic instabilities. Turbulence and unstable coherent flows.<br />
<br />
[http://math.mit.edu/~lzepeda/ Leonardo Andrés Zepeda-Núñez:] (MIT, 2015) machine learning, numerical analysis, wave propagation, inverse problems.<br />
<br />
[https://hanbaeklyu.com/ Hanbaek Lyu] (Ohio State, 2018) discrete probability, dynamical systems, networks, optimization, machine learning <br />
<br />
[https://sites.google.com/site/albertodelpia/ Alberto Del Pia]: (Padova, 2009) mathematical optimization, discrete optimization, data science, theoretical computer science<br />
<!-- [http://www.math.wisc.edu/~kiselev/ Alex (Sasha) Kiselev:] (CalTech, 1997) partial differential equations, Fourier analysis and applications in fluid mechanics, combustion, mathematical biology and Schr&ouml;dinger operators.--><br />
<!-- [http://www.math.wisc.edu/~zlatos/ Andrej Zlatos:] (Caltech, 2003) partial differential equations, combustion, fluid dynamics, Schrödinger operators, orthogonal polynomials--><br />
<!-- [http://www.math.wisc.edu/~jin/ Shi Jin:] (Arizona, 1991) applied & computational mathematics. --><br />
<!-- [http://www.math.wisc.edu/~mitchell/ Julie Mitchell:] (Berkeley, 1998) computational mathematics, structural biology. --><br />
<br />
<br><br />
<br />
== Postdoctoral fellows and researchers ==<br />
<br />
[http://vv811a.math.wisc.edu/persepolis/index.php/members/10-members/30-majid-arabgol Majid Arabgol:]<br />
HPC & Visualization Research Scholar<br />
<br />
[http://www.math.wisc.edu/~boonkasa Anakewit (Tete) Boonkasame:] (UW Madison, 2012)<br />
<br />
[http://mbudisic.wordpress.com Marko Budi&#x161;i&#x107;:] (UC Santa Barbara, 2012) dynamical systems<br />
<br />
[http://www.math.wisc.edu/~caiy Yongyong Cai:] (National University of Singapore, 2012)<br />
<br />
[https://artioevans.wordpress.com/ Arthur Evans:] (UCSD, 2011) soft matter, complex fluids<br />
<br />
[https://www.math.wisc.edu/~pgera/ Prerna Gera:] (Buffalo, 2018) fluid-structure interactions<br />
<br />
[https://people.math.wisc.edu/~tgchandler/ Thomas Chandler:] (Oxford, 2021) soft matter, complex fluids<br />
<br />
[http://www.math.wisc.edu/~mjohnston3 Matthew Johnston:] (University of Waterloo, 2011) dynamical systems<br />
<br />
<!-- [http://www.math.wisc.edu/~dwei/ Dongming Wei:] (Maryland, 2007) nonlinear partial differential equations, applied analysis, and numerical computation. --><br />
<br />
<br><br />
<br />
== Current graduate students ==<br />
<br />
{| class="wikitable sortable" style="margin-left: auto; margin-right: auto; border: none;"<br />
|+ List of current graduate students (updated summer of 2021).<br />
|-<br />
! Student !! Advisor (1) !! Advisor (2) !! Program Start Year !! Research Area<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Zinan Wang] || Sigurd Angenent || || || <br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Jeffrey Covington] || Nan Chen || || 2018 || <br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Xiao Hou] || Nan Chen || Qin Li || || <br />
|-<br />
| [https://sites.google.com/wisc.edu/yingdali Yingda Li] || Nan Chen || || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Yuchen Li] || Nan Chen || || ||<br />
|-<br />
|Sanchita Chakraborty<br />
|Nan Chen<br />
|<br />
|2022<br />
|<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Haley Colgate] || Amy Cochran || || 2020 ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Enkhzaya "Eza" Enkhtaivan] || Amy Cochran || || ||<br />
|-<br />
| [https://sites.google.com/view/jiaxinjin/ Jiaxin Jin] || Gheorghe Craciun || Chanwoo Kim || ||<br />
|-<br />
| [https://sites.google.com/site/mathjennyy/ Jenny Yeon] || Gheorghe Craciun || || ||<br />
|-<br />
| [https://sites.google.com/view/pollyyu Polly Yu] || Gheorghe Craciun || || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Hongxu Chen] || Chanwoo Kim || Qin Li || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Shi Chen] || Qin Li || || ||<br />
|-<br />
| [https://people.math.wisc.edu/~zding49/ Zhiyan Ding] || Qin Li || || ||<br />
|-<br />
| [https://sites.google.com/wisc.edu/nair-anjali/home Anjali Nair] || Qin Li || || 2018 ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Jenny Wei] || Qin Li || Yingyu Liang || ||<br />
|-<br />
| [https://borongzhang.com/ Borong Zhang] || Qin Li || Leonardo Zepeda-Núñez || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Parvathi Madathil Kooloth] || Leslie Smith || || ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Varun Gudibanda] || Leslie Smith || || 2020 ||<br />
|-<br />
| [https://www.physics.wisc.edu/directory/lough-wilson-bennett/ Wilson Lough] || Saverio Spagnolie || || 2018 ||<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Tianhong Huang] || Samuel Stechmann || || ||<br />
|-<br />
| [https://jasonltorchinsky.github.io/ Jason Torchinsky] || Samuel Stechmann || || 2018 || Data assimilation, multi-model communication, atmospheric modelling<br />
|-<br />
| [https://math.wisc.edu/graduate-students/ Carrie Hongfei Chen] || Jean-Luc Thiffeault || || ||<br />
|-<br />
| [https://sites.google.com/wisc.edu/yufeng-webpage/home Yu Feng] || Jean-Luc Thiffeault || || ||<br />
|-<br />
| [https://www.math.wisc.edu/~boakley/ Bryan Oakley] || Jean-Luc Thiffeault || || ||<br />
|}<br />
<br />
<br />
<br />
<!-- Past students: --><br />
<!-- [https://math.wisc.edu/graduate-students/ Liu Liu:] Student of Shi Jin. --><br />
<!-- Yun Sun: Student of David Anderson.--><br />
<!-- [http://www.math.wisc.edu/~zhou/ Zhennan Zhou:] Student of Shi Jin.--><br />
<!-- [http://www.math.wisc.edu/~mueller/ Peter Mueller:] Student of Jean-Luc Thiffeault.--><br />
<!-- [http://www.math.wisc.edu/~jefferis/ Leland Jefferis:] Student of Shi Jin. --><br />
<!-- [http://www.math.wisc.edu/~hu/ Jingwei Hu:] Student of Shi Jin. --><br />
<!-- [http://www.math.wisc.edu/~yan/ Bokai Yan:] Student of Shi Jin. --><br />
<!-- [http://www.math.wisc.edu/~crompton/ Bryan Crompton:] Student of Saverio Spagnolie. --><br />
<!-- [http://www.math.wisc.edu/~whmitchell/ Will Mitchell:] Student of Saverio Spagnolie. --><br />
<!--Zhan Wang: Student of Paul Milewski.--><br />
<!--Anekewit (Tete) Boonkasame: Student of Paul Milewski.--><br />
<!--Peng Qi: Student of Shi Jin. --><br />
<!--Li (Aug) Wang: Student of Shi Jin. --><br />
<!-- Lei Li: Student of Saverio Spagnolie. --><br />
<!--Li Wang: Student of Leslie Smith. --><br />
<!--David Seal: Student of James Rossmanith. --><br />
<!--E. Alec Johnson: Student of James Rossmanith. --><br />
<!--Hesam Dashti: MSc Student of Amir Assadi.--><br />
<!--Qiang Deng: Student of Leslie Smith.--><br />
<!--[http://www.math.wisc.edu/~matz/ Sarah Tumasz:] Student of Jean-Luc Thiffeault.--><br />
<!--[http://www.math.wisc.edu/~qinli/ Qin Li:] Student of Shi Jin.--><br />
<!--Yongtao Cheng: Student of James Rossmanith.--><br />
<!-- [http://www.math.wisc.edu/~mueller/ Peter Mueller:] Student of Jean-Luc Thiffeault. --><br />
<br />
<br><br />
<br />
== Graduate course offerings ==<br />
<br />
=== Fall 2022 ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (David Keating, Erik Bates)<br />
* Math 703: Methods of Applied Mathematics I (Gheorghe Craciun)<br />
* Math 714: Methods of Computational Math I (Sam Stechmann)<br />
* Math 717: Stochastic Computational Methods (Nan Chen)<br />
<br />
=== Spring 2023 ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (David Keating, Sebastien Roch)<br />
* Math 704: Methods of Applied Mathematics II (Jean-Luc Thiffeault)<br />
* Math 715: Methods of Computational Math II (Maurice Fabien)<br />
* Math 801: Topics in Applied Mathematics: Computational Fluid Dynamics (Saverio Spagnolie)<br />
<br />
<br />
<!--=== [http://www.math.wisc.edu/graduate/gcourses_fall Spring 2021] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (Scott Smith, Erik Bates, Tetiana Shcherbyna)<br />
* Math 704: Methods of Applied Mathematics II (Jean-Luc Thiffeault)<br />
* Math 705: Mathematical Fluid Dynamics (Leslie Smith)<br />
* Math 715: Methods of Computational Math II (Leonardo Andrés Zepeda-Núñez)<br />
* Math 716: Ordinary Differential Equations (Sigurd Angenent)<br />
* Math 801: Topics in Applied Mathematics (Gheorghe Craciun)<br />
* Math 807: Dynamical Systems (Hung Tran)<br />
* Math 820: Partial Differential Equations (Chanwoo Kim)<br />
<br />
<!--=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2021] ===<br />
<br />
* Math 623: Complex Analysis (Betsy Stovall)<br />
* Math 627: Introduction to Fourier Analysis (Sergey Denisov)<br />
* Math 632: Introduction to Stochastic Processes (Vadim Gorin, Benedek Valko)<br />
* Math 703: Methods of Applied Mathematics I (Gheorghe Craciun)<br />
* Math 714: Methods of Computational Math I (Leonardo Andrés Zepeda-Núñez)<br />
* Math 821: Advanced Topics in Real Analysis [Fluid Dynamics] (Mihaela Ifrim)<br />
* Math 833: Topics in the Theory of Probability [Stochastic Computational Methods] (Nan Chen)<br />
<br />
<br />
<!--=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2019] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (David Anderson, Timo Seppalainen, Benedek Valko)<br />
* Math 703: Methods of Applied Mathematics I (Saverio Spagnolie)<br />
* Math 705: Mathematical Fluid Dynamics (Leslie Smith)<br />
* Math 714: Methods of Computational Math I (Sam Stechmann)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2020] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (TBA)<br />
* Math 704: Methods of Applied Mathematics II (TBA)<br />
* Math 715: Methods of Computational Math II (TBA)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2016] ===<br />
<br />
* Math 606: Mathematical Methods for Structural Biology (Julie Mitchell)<br />
* Math 632: Introduction to Stochastic Processes (Sebastien Roch)<br />
* Math 703: Methods of Applied Mathematics I (Gheorghe Craciun)<br />
* Math 714: Methods of Computational Math I (Shi Jin)<br />
* Math 801: Topics in Applied Mathematics: Hydrodynamic instabilities and bifurcations (Fabian Waleffe)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2017] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (Daniele Cappelletti, Jun Yin)<br />
* Math 704: Methods of Applied Mathematics II (Jean-Luc Thiffeault)<br />
* Math 715: Methods of Computational Math II (Qin Li)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2014] ===<br />
<br />
* Math 606: Mathematical Methods for Structural Biology (Julie Mitchell)<br />
* Math 632: Introduction to Stochastic Processes (Sebastien Roch, Benedek Valko)<br />
* Math 703: Methods of Applied Mathematics I (Gheorghe Craciun)<br />
* Math 714: Methods of Computational Math I (Sam Stechmann)<br />
* Math 801: Topics in Applied Mathematics (Shi Jin)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2015] ===<br />
<br />
* Math 632: Introduction to Stochastic Processes (Sebastien Roch, Jun Yin)<br />
* Math 704: Methods of Applied Mathematics II (Sam Stechmann)<br />
* Math 715: Methods of Computational Math II (Saverio Spagnolie)<br />
* Math 801: Topics in Applied Mathematics: Nonlinear dynamics and applications (Gheorghe Craciun) --><br />
<br />
<!-- === [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2013] ===<br />
<br />
* Math 605: Stochastic Methods for Biology (David Anderson)<br />
* Math 632: Introduction to Stochastic Processes (Gregory Shinault)<br />
* Math 703: Methods of Applied Mathematics 1 (Jean-Luc Thiffeault)<br />
* Math 714: Methods of Computational Math I (Shi Jin)<br />
* Math 826: Advanced Topics in Functional Analysis and Differential Equations (Alexander Kiselev)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2014] ===<br />
<br />
<br />
* Math 609: Mathematical Methods for Systems Biology (Gheorghe Craciun)<br />
* Math 632: Introduction to Stochastic Processes (Gregory Shinault)<br />
* Math 704: Methods of Applied Mathematics II (Sam Stechmann)<br />
* Math 715: Methods of Computational Math II (Jean-Luc Thiffeault)<br />
* Math 801: Topics in Applied Mathematics: Biological Continuum Mechanics (Saverio Spagnolie) --><br />
<br />
<br />
<!-- === [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2012] ===<br />
<br />
* Math 606: Mathematical Methods for Structural Biology (Julie Mitchell)<br />
* Math 632: Introduction to Stochastic Processes (David Anderson)<br />
* Math 703: Methods of Applied Mathematics 1 (Jean-Luc Thiffeault)<br />
* Math 705: Mathematical Fluid Dynamics (Saverio Spagnolie)<br />
* Math 714: Methods of Computational Math I (Shi Jin)<br />
* Math 833: Topics in Probability - Stochastic Processes in Evolution and Genetics (Sebastien Roch)<br />
* Math 842: Topics in Applied Algebra for EE/Math/CS students (Shamgar Gurevich)<br />
<br />
=== [http://www.math.wisc.edu/graduate/gcourses_spring Spring 2013] ===<br />
<br />
* Math 704: Methods of Applied Mathematics 2 (Sam Stechmann)<br />
* Math 715: Methods of Computational Math II (Saverio Spagnolie)<br />
* Math 801: Topics in Applied Mathematics -- Mathematical Aspects of Mixing (Jean-Luc Thiffeault) --><br />
<br />
<!-- === Spring 2012 ===<br />
* Math 714: [http://www.math.wisc.edu/math-714-scientific-computing Methods of Computational Math I] (S. Stechmann) --><br />
<br />
<br />
<!--<br />
=== [http://www.math.wisc.edu/graduate/gcourses_fall Fall 2011] ===<br />
<br />
* Math 605: [http://www.math.wisc.edu/math-727-calculus-variations-0 Stochastic Methods for Biology] (D. Anderson)<br />
* Math 703: [http://www.math.wisc.edu/math-703-methods-applied-mathematics-i Methods of Applied Mathematics II] (L. Smith)<br />
* Math 707: [http://www.math.wisc.edu/math707-ema700-theory-elasticity Theory of Elasticity] (F. Waleffe)<br />
* Math 714: [http://www.math.wisc.edu/math-714-scientific-computing Methods of Computational Math I] (J. Mitchell)<br />
* Math 801: [http://www.math.wisc.edu/801-waves-fluids Comp Math Applied to Biology] (A. Assadi)<br />
* Math 837: [http://www.math.wisc.edu/math-837-topics-numerical-analysis Topics in Numerical Analysis] (S. Jin)<br />
--><br />
<br />
<!--<br />
Spring 2011:<br />
* Math 609: [https://www.math.wisc.edu/609-mathematical-methods-systems-biology Mathematical Methods for Systems Biology] (G. Craciun)<br />
* Math 704: [https://www.math.wisc.edu/704-methods-applied-mathematics-2 Methods of Applied Mathematics II] (S. Stechmann)<br />
* Math/CS 715: [https://www.math.wisc.edu/715-methods-computational-math-ii Methods of Computational Math II] (S. Jin)<br />
* Math 801: [https://www.math.wisc.edu/math-801-hydrodynamic-instabilities-chaos-and-turbulence Hydrodynamic Instabilities, Chaos and Turbulence] (F. Waleffe)<br />
* Math 826: [https://www.math.wisc.edu/826-Functional-Analysis Partial Differential Equations in Fluids and Biology] (A. Kiselev)<br />
* Math/CS 837: [https://www.math.wisc.edu/837-Numerical-Analysis Numerical Methods for Hyperbolic PDEs] (J. Rossmanith)<br />
--><br />
<br />
<br><br />
<br />
----<br />
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[http://www3.clustrmaps.com/stats/maps-no_clusters/www.math.wisc.edu-wiki-index.php-Applied-thumb.jpg Locations of visitors to this page] ([http://www3.clustrmaps.com/user/195f39ef Clustermaps])</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Spring_2023_Analysis_Seminar&diff=23818Spring 2023 Analysis Seminar2022-10-05T14:21:20Z<p>Nagreen: </p>
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<div>{| class="wikitable"<br />
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<hr />
<div>[https://www.math.wisc.edu/wiki/index.php/Analysis_Seminar Current schedule]<br />
<br />
Past Analysis seminars:<br />
<br />
*[[Spring 2023 Analysis Seminar]]<br />
*Fall 2022 Analysis Seminar<br />
*[[Fall 2021 and Spring 2022 Analysis Seminars]]<br />
*[[Fall 2020 and Spring 2021 Analysis Seminars]]<br />
*[[Fall 2019 and Spring 2020 Analysis Seminars]]<br />
*[[Fall 2018 and Spring 2019 Analysis Seminars]]<br />
*[[Fall 2017 and Spring 2018 Analysis Seminars]]<br />
*[[Spring 2017 Analysis Seminars]]<br />
*[http://www.math.wisc.edu/~seeger/fall16.html Fall 2016]<br />
*[http://www.math.wisc.edu/~seeger/spring16.html Spring 2016]<br />
*[http://www.math.wisc.edu/~seeger/fall15.html Fall 2015]<br />
*[http://www.math.wisc.edu/~seeger/spring15.html Spring 2015]<br />
*[http://www.math.wisc.edu/~seeger/fall14.html Fall 2014]<br />
*[http://www.math.wisc.edu/~seeger/spring14.html Spring 2014]<br />
*[http://www.math.wisc.edu/~seeger/fall13.html Fall 2013]<br />
*[http://www.math.wisc.edu/~seeger/spring13.html Spring 2013]<br />
*[http://www.math.wisc.edu/~seeger/fall12.html Fall 2012]<br />
*[http://www.math.wisc.edu/~seeger/spring12.html Spring 2012]<br />
*[http://www.math.wisc.edu/~seeger/fall11.html Fall 2011]<br />
*[http://www.math.wisc.edu/~seeger/spring11.html Spring 2011]<br />
*[http://www.math.wisc.edu/~seeger/fall10.html Fall 2010]<br />
*[http://www.math.wisc.edu/~seeger/spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~seeger/fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~seeger/spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~seeger/fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~seeger/spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~seeger/fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~seeger/spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~seeger/fall06.html Fall 2006]<br />
*[http://www.math.wisc.edu/~seeger/spring06.html Spring 2006]<br />
*[http://www.math.wisc.edu/~seeger/fall05.html Fall 2005]<br />
*[http://www.math.wisc.edu/~seeger/spring05.html Spring 2005]<br />
*[http://www.math.wisc.edu/~seeger/fall04.html Fall 2004]<br />
*[http://www.math.wisc.edu/~seeger/summer04.html Summer 2004]<br />
*[http://www.math.wisc.edu/~seeger/spring04.html Spring 2004]<br />
*[http://www.math.wisc.edu/~seeger/fall03.html Fall 2003]<br />
*[http://www.math.wisc.edu/~seeger/spring03.html Spring 2003]<br />
*[http://www.math.wisc.edu/~seeger/fall02.html Fall 2002]<br />
*[http://www.math.wisc.edu/~seeger/spring02.html Spring 2002]<br />
*[http://www.math.wisc.edu/~seeger/fall01.html Fall 2001]<br />
*[http://www.math.wisc.edu/~seeger/spring01.html Spring 2001]<br />
*[http://www.math.wisc.edu/~seeger/fall00.html Fall 2000]<br />
*[http://www.math.wisc.edu/~seeger/spring00.html Spring 2000]<br />
*[http://www.math.wisc.edu/~seeger/fall99.html Fall 1999]<br />
*[http://www.math.wisc.edu/~seeger/spring99.html Spring 1999]<br />
*[http://www.math.wisc.edu/~seeger/fall98 Fall 1998]<br />
*[http://www.math.wisc.edu/~seeger/spring98.html Spring 1998]<br />
*[http://www.math.wisc.edu/~seeger/fall97.html Fall 1997]<br />
*[http://www.math.wisc.edu/~seeger/spring97.html Spring 1997]<br />
*[http://www.math.wisc.edu/~seeger/fall96.html Fall 1996]<br />
*[http://www.math.wisc.edu/~seeger/spring96.html Spring 1996]<br />
*[http://www.math.wisc.edu/~seeger/fall95.html Fall 1995]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Previous_Analysis_seminars&diff=23815Previous Analysis seminars2022-10-05T14:18:27Z<p>Nagreen: </p>
<hr />
<div>[https://www.math.wisc.edu/wiki/index.php/Analysis_Seminar Current schedule]<br />
<br />
Past Analysis seminars:<br />
<br />
*[[Spring 2023 Analysis Seminar]]<br />
*[[Fall 2022 Analysis Seminar]]<br />
*[[Fall 2021 and Spring 2022 Analysis Seminars]]<br />
*[[Fall 2020 and Spring 2021 Analysis Seminars]]<br />
*[[Fall 2019 and Spring 2020 Analysis Seminars]]<br />
*[[Fall 2018 and Spring 2019 Analysis Seminars]]<br />
*[[Fall 2017 and Spring 2018 Analysis Seminars]]<br />
*[[Spring 2017 Analysis Seminars]]<br />
*[http://www.math.wisc.edu/~seeger/fall16.html Fall 2016]<br />
*[http://www.math.wisc.edu/~seeger/spring16.html Spring 2016]<br />
*[http://www.math.wisc.edu/~seeger/fall15.html Fall 2015]<br />
*[http://www.math.wisc.edu/~seeger/spring15.html Spring 2015]<br />
*[http://www.math.wisc.edu/~seeger/fall14.html Fall 2014]<br />
*[http://www.math.wisc.edu/~seeger/spring14.html Spring 2014]<br />
*[http://www.math.wisc.edu/~seeger/fall13.html Fall 2013]<br />
*[http://www.math.wisc.edu/~seeger/spring13.html Spring 2013]<br />
*[http://www.math.wisc.edu/~seeger/fall12.html Fall 2012]<br />
*[http://www.math.wisc.edu/~seeger/spring12.html Spring 2012]<br />
*[http://www.math.wisc.edu/~seeger/fall11.html Fall 2011]<br />
*[http://www.math.wisc.edu/~seeger/spring11.html Spring 2011]<br />
*[http://www.math.wisc.edu/~seeger/fall10.html Fall 2010]<br />
*[http://www.math.wisc.edu/~seeger/spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~seeger/fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~seeger/spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~seeger/fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~seeger/spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~seeger/fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~seeger/spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~seeger/fall06.html Fall 2006]<br />
*[http://www.math.wisc.edu/~seeger/spring06.html Spring 2006]<br />
*[http://www.math.wisc.edu/~seeger/fall05.html Fall 2005]<br />
*[http://www.math.wisc.edu/~seeger/spring05.html Spring 2005]<br />
*[http://www.math.wisc.edu/~seeger/fall04.html Fall 2004]<br />
*[http://www.math.wisc.edu/~seeger/summer04.html Summer 2004]<br />
*[http://www.math.wisc.edu/~seeger/spring04.html Spring 2004]<br />
*[http://www.math.wisc.edu/~seeger/fall03.html Fall 2003]<br />
*[http://www.math.wisc.edu/~seeger/spring03.html Spring 2003]<br />
*[http://www.math.wisc.edu/~seeger/fall02.html Fall 2002]<br />
*[http://www.math.wisc.edu/~seeger/spring02.html Spring 2002]<br />
*[http://www.math.wisc.edu/~seeger/fall01.html Fall 2001]<br />
*[http://www.math.wisc.edu/~seeger/spring01.html Spring 2001]<br />
*[http://www.math.wisc.edu/~seeger/fall00.html Fall 2000]<br />
*[http://www.math.wisc.edu/~seeger/spring00.html Spring 2000]<br />
*[http://www.math.wisc.edu/~seeger/fall99.html Fall 1999]<br />
*[http://www.math.wisc.edu/~seeger/spring99.html Spring 1999]<br />
*[http://www.math.wisc.edu/~seeger/fall98 Fall 1998]<br />
*[http://www.math.wisc.edu/~seeger/spring98.html Spring 1998]<br />
*[http://www.math.wisc.edu/~seeger/fall97.html Fall 1997]<br />
*[http://www.math.wisc.edu/~seeger/spring97.html Spring 1997]<br />
*[http://www.math.wisc.edu/~seeger/fall96.html Fall 1996]<br />
*[http://www.math.wisc.edu/~seeger/spring96.html Spring 1996]<br />
*[http://www.math.wisc.edu/~seeger/fall95.html Fall 1995]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Fall_2022_analysis_seminar&diff=23814Fall 2022 analysis seminar2022-10-05T14:17:09Z<p>Nagreen: added Spring 2023 Analysis Seminar page</p>
<hr />
<div><br />
The 2022-2023 Analysis Seminar will be organized by Shaoming Guo. <br />
The regular time and place for the Seminar will be Tuesdays at 4:00 p.m. in Van Vleck B139 (in some cases the seminar may be scheduled at different time to accommodate speakers).<br />
If you would like to subscribe to the Analysis seminar list, send a blank email to analysis+join (at) g-groups (dot) wisc (dot) edu. If you are from an institution different than UW-Madison, please send as well as an additional email to Shaoming. <br />
If you'd like to suggest speakers for the spring semester please contact Shaoming.<br />
<br />
All talks will be in-person unless otherwise specified. <br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Analysis Seminar Schedule =<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
|align="left" | '''institution'''<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|08.23<br />
|Gustavo Garrigós<br />
|University of Murcia<br />
|[[#Gustavo Garrigós | Approximation by N-term trigonometric polynomials and greedy algorithms]]<br />
| Andreas Seeger<br />
|-<br />
|08.30<br />
|Simon Myerson<br />
|Warwick<br />
|[[#Simon Myerson | Forms of the Circle Method]]<br />
|Shaoming Guo<br />
|-<br />
|09.13 <br />
(first week of semester)<br />
| Zane Li<br />
| UW Madison<br />
|[[Fall 2022 analysis seminar#Zane Li|A decoupling interpretation of an old argument for Vinogradov's Mean Value Theorem]]<br />
| Analysis group<br />
|-<br />
|09.16 <br />
(Friday, 1:20-2:10, Room B139)<br />
|Franky Li<br />
|UW Madison<br />
|[[#Jianhui Li | Affine restriction estimates for surfaces in R^3 via decoupling]]<br />
|Analysis group<br />
|-<br />
|09.20 (Joint with PDE and Geometric Analysis seminar)<br />
| Andrej Zlatoš<br />
| UCSD<br />
|[[#Andrej Zlatoš | Homogenization in front propagation models ]]<br />
| Hung Tran<br />
|-<br />
|09.23 Friday, Colloquium<br />
| Pablo Shmerkin<br />
|UBC<br />
|[[#Pablo Shmerkin | Incidences and line counting: from the discrete to the fractal setting]]<br />
| Shaoming Guo and Andreas Seeger<br />
|-<br />
|09.23-09.25<br />
| [https://sites.google.com/view/harmonic-workshop-madison/main-page RTG workshop in Harmonic Analysis]<br />
|<br />
|[[#linktoabstract | ]]<br />
| Shaoming Guo and Andreas Seeger<br />
|-<br />
|09.27 <br />
(online, special time, 3-4pm)<br />
| Michael Magee <br />
| Durham<br />
|[[#Michael Magee | The maximal spectral gap of a hyperbolic surface]]<br />
| Simon Marshall<br />
|-<br />
|10.04<br />
| Philip Gressman<br />
| UPenn<br />
|Sublevel Set Estimates in Higher Dimensions: Symmetry and Uniformity<br />
| Shaoming Guo<br />
|-<br />
|10.11<br />
| Detlef Müller<br />
| CAU Kiel<br />
|[[#Detlef Müller | Maximal averages along hypersurfaces: a geometric conjecture and further progress for 2-surfaces ]]<br />
| Betsy Stovall and Andreas Seeger<br />
|-<br />
|10.14 (1:00 PM Friday. Joint with Geometry & Topology Seminar)<br />
| Min Ru<br />
| U of Houston<br />
|[[Fall 2022 analysis seminar#Madelyne M. Ru |The K-stability and Nevanlinna/Diophantine theory]]<br />
| Xianghong Gong<br />
|-<br />
|10.18<br />
| Madelyne M. Brown<br />
| UNC<br />
|[[Fall 2022 analysis seminar#Madelyne M. Brown|Fourier coefficients of restricted eigenfunctions]]<br />
| Betsy Stovall<br />
|-<br />
|10.24 (Monday, B135)<br />
| Milivoje Lukic<br />
| Rice<br />
|An approach to universality using Weyl m-functions<br />
| Sergey Denisov<br />
|-<br />
|11.01<br />
| Ziming Shi<br />
| Rutgers<br />
|[[#linktoabstract | Title ]]<br />
| Xianghong Gong<br />
|-<br />
|11.04 (Friday, 1:20-2:10, in room tbd)<br />
|Sarah Tammen<br />
|MIT<br />
|<br />
|Betsy Stovall<br />
|-<br />
|11.08<br />
| Robert Fraser<br />
| Wichita State University<br />
|[[#linktoabstract | Title ]]<br />
| Andreas Seeger<br />
|-<br />
|11.15<br />
| Brian Cook<br />
| Virginia Tech<br />
|[[#linktoabstract | Title ]]<br />
| Brian Street<br />
|-<br />
|11.22<br />
| Thanksgiving<br />
| <br />
|<br />
| <br />
|-<br />
|11.29<br />
| Jaume de Dios Pont<br />
| UCLA<br />
|[[#linktoabstract | Title ]]<br />
| Betsy Stovall<br />
|-<br />
|12.06<br />
| Shengwen Gan<br />
| MIT<br />
|[[#linktoabstract | Title ]]<br />
| Shaoming Guo and Andreas Seeger<br />
|-<br />
|12.13<br />
|Óscar Domínguez<br />
|Universidad Complutense Madrid and University of Lyons<br />
|[[#linktoabstract | Title ]]<br />
|Andreas Seeger and Brian Street<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|Spring 2023<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|3.14<br />
|Liding Yao<br />
|Ohio State<br />
|<br />
|Brian Street<br />
|-<br />
<br />
|}<br />
<br />
<br />
[[Spring 2023 Analysis Seminar]]<br />
<br />
=Abstracts=<br />
<br />
===Gustavo Garrigós===<br />
<br />
Title: Approximation by N-term trigonometric polynomials and greedy algorithms<br />
<br />
Link to Abstract: [https://people.math.wisc.edu/~seeger/gg-abstract.pdf]<br />
<br />
===Simon Myerson===<br />
<br />
Title: Forms of the circle method<br />
<br />
Abstract: The circle method is an analytic proof strategy, typically used in number theory when one wants to estimate the number of integer lattice points in some interesting set. Traditionally the first step is to evaluate the innocent integral $ \int_0^1 e^{2 \pi i t n} dt $ to give 1 if $ n = 0 $ and 0 if $ n $ is any other integer. Since Heath-Brown’s delta-method in the 90s this simplest step has been embellished with carefully constructed partitions of unity. In this informal discussion I will interpret these as different versions of the circle method and suggest how to understand their relative advantages.<br />
<br />
===Andrej Zlatos===<br />
<br />
Title: Homogenization in front propagation models<br />
<br />
Abstract: Homogenization is a general principle that the dynamics of physical processes occurring in periodic or random environments often become effectively homogeneous in the long-time-large-scale limit. I will presents results showing that homogenization occurs for reaction-diffusion equations with both time-periodic-spatially-random and space-time-random KPP reactions and coefficients. These results rely on two crucial new tools: virtual linearity of KPP reaction-diffusion dynamics and a non-autonomous versions of Kingman’s subadditive ergodic theorem.<br />
<br />
<br />
<br />
<br />
<br />
===Zane Li===<br />
<br />
Title: A decoupling interpretation of an old argument for Vinogradov's Mean Value Theorem <br />
<br />
Abstract: There are two proofs of Vinogradov's Mean Value Theorem (VMVT), the harmonic analysis decoupling proof by Bourgain, Demeter, and Guth from 2015 and the number theoretic efficient congruencing proof by Wooley from 2017. While there has been recent work illustrating the relation between these two methods, VMVT has been around since 1935. It is then natural to ask: What does old partial progress on VMVT look like in harmonic analysis language? How similar or different does it look from current decoupling proofs? We talk about a refinement of a 1973 argument of Karatsuba that showed partial progress towards VMVT and interpret this in decoupling language. This yields an argument that only uses rather simple geometry of the moment curve. This is joint work with Brian Cook, Kevin Hughes, Olivier Robert, Akshat Mudgal, and Po-Lam Yung.<br />
<br />
===Jianhui Li===<br />
<br />
Title: Affine restriction estimates for surfaces in \mathbb{R}^3 via decoupling<br />
<br />
Abstract: We will discuss some L^2 restriction estimates for smooth compact surfaces in \mathbb{R}^3 with weights that respect affine transformations. The key ingredient is a decoupling inequality. The results are also uniform for polynomial surfaces of bounded degrees and coefficients. Part of the work is joint with Tongou Yang.<br />
<br />
<br />
===Pablo Shmerkin===<br />
<br />
Title: Incidences and line counting: from the discrete to the fractal setting<br />
<br />
Abstract: How many lines are spanned by a set of planar points?. If the points are collinear, then the answer is clearly "one". If they are not collinear, however, several different answers exist when sets are finite and "how many" is measured by cardinality. I will discuss a bit of the history of this problem and present a recent extension to the continuum setting, obtained in collaboration with T. Orponen and H. Wang. No specialized background will be assumed.<br />
<br />
=== Michael Magee===<br />
<br />
Title: The maximal spectral gap of a hyperbolic surface<br />
<br />
Abstract: A hyperbolic surface is a surface with metric of constant curvature -1. The spectral gap between the first two eigenvalues of the Laplacian on a closed hyperbolic surface contains a good deal of information about the surface, including its connectivity, dynamical properties of its geodesic flow, and error terms in geodesic counting problems. For arithmetic hyperbolic surfaces the spectral gap is also the subject of one of the biggest open problems in automorphic forms: Selberg's eigenvalue conjecture.<br />
<br />
A conjecture of Buser from the 1980s stated that there exists a sequence of closed hyperbolic surfaces with genera tending to infinity and spectral gap tending to 1/4. (The value 1/4 here is the asymptotically optimal one.) We proved that such a sequence does exist. I'll discuss the very interesting background of this problem in detail as well as some ideas of the proof.<br />
<br />
This is joint work with Will Hide.<br />
<br />
=== Philip Gressman===<br />
<br />
Title: Sublevel Set Estimates in Higher Dimensions: Symmetry and Uniformity<br />
<br />
Abstract: Using even simple derivative bounds, it is possible to understand the behavior of smooth functions of a single real variable in very precise ways. In contrast, when one moves to dimensions 2 and higher, current best approaches fail to yield the same kind of sharp, uniform inequalities that are relatively easy to obtain in 1D. I will discuss a number of related problems which attempt to illuminate some of the reasons for this discrepancy and to formulate new ways of working in higher dimensions to recover some of the robustness that is available in 1D. Of particular interest will be sublevel sets and uniform estimates for integrals of the sort found in the theory of critical integrability exponents. One main result will show how machinery developed for the study of affine Hausdorff measure can be used to build nonlinear differential operators whose nonvanishing implies uniform sublevel set estimates and bounds for related integrals.<br />
<br />
<br />
===Detlef Müller===<br />
<br />
Tirlw: Maximal averages along hypersurfaces: a ``geometric conjecture'' and further progress for 2-surfaces.<br />
<br />
Link to Abstract: [https://people.math.wisc.edu/~seeger/detlefm-9-2022-abstract.pdf]<br />
<br />
===Madelyne M. Brown===<br />
<br />
Title: Fourier coefficients of restricted eigenfunctions<br />
<br />
Abstract: We will discuss the growth of Laplace eigenfunctions on a compact manifold when restricted to a submanifold. We analyze the behavior of the restricted eigenfunctions by studying their Fourier coefficients with respect to an arbitrary orthonormal basis for the submanifold. We give an explicit bound on these coefficients depending on how the defect measures for the two collections of functions, the eigenfunctions and the basis, relate.<br />
<br />
===Milivoje Lukic===<br />
<br />
Title: An approach to universality using Weyl m-functions<br />
<br />
Abstract: <br />
<br />
I will describe an approach to universality limits for orthogonal polynomials on the real line which is completely local and uses only the boundary behavior of the Weyl $m$-function at the point. We show that bulk universality of the Christoffel--Darboux kernel holds for any point where the imaginary part of the $m$-function has a positive finite nontangential limit. This approach is based on studying a matrix version of the Christoffel--Darboux kernel and the realization that bulk universality for this kernel at a point is equivalent to the fact that the corresponding $m$-function has normal limits at the same point. Our approach automatically applies to other self-adjoint systems with $2\times 2$ transfer matrices such as continuum Schr\"odinger and Dirac operators. We also obtain analogous results for orthogonal polynomials on the unit circle. This is joint work with Benjamin Eichinger and Brian Simanek.<br />
<br />
<br />
===Min Ru===<br />
<br />
Title: The K-stability and Nevanlinna/Diophantine theory<br />
<br />
Abstract: In the recent paper with P. Vojta, we introduced the so-called beta-constant, and used it to extend the Cartan's Second Main Theorem in Nevanlinna theory and Schmidt's subspace theorem in Diophantine approximation. It turns out the beta-constant is also used in the algebro-geometric stability criterion in the Fano's case. In this talk, I'll describe and explore the somewhat mysterious connection. The talk is based on the recent joint paper with Yan He entitled "The stability threshold and Diophantine approximation", Proc. AMS, 2022.<br />
<br />
<br />
===Name===<br />
<br />
Title<br />
<br />
Abstract<br />
<br />
<br />
<br />
<br />
<br />
<br />
[https://www.math.wisc.edu/wiki/index.php/Previous_Analysis_seminars Links to previous analysis seminars]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=23709SIAM Student Chapter Seminar2022-09-19T16:31:51Z<p>Nagreen: /* Fall 2022 */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 3:30 PM<br />
*'''Where:''' 9th floor lounge (we will also broadcast the virtual talks on the 9th floor lounge with refreshments)<br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
==Fall 2022==<br />
{|<br />
!Date<br />
!Location<br />
!Speaker<br />
!Title<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|}<br />
<br />
<br />
<br />
<br />
==Abstracts==<br />
<br />
<br />
==Past Semesters==<br />
*[[Spring 2022 SIAM|Spring 2022]]<br />
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=23708SIAM Student Chapter Seminar2022-09-19T16:31:00Z<p>Nagreen: /* Fall 2022 */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 3:30 PM<br />
*'''Where:''' 9th floor lounge (we will also broadcast the virtual talks on the 9th floor lounge with refreshments)<br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
==Fall 2022==<br />
{| class="wikitable"<br />
|+<br />
!Date<br />
!Location<br />
!Speaker<br />
!Title<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|-<br />
|<br />
|<br />
|<br />
|<br />
|}<br />
<br />
<br />
<br />
<br />
==Abstracts==<br />
<br />
<br />
==Past Semesters==<br />
*[[Spring 2022 SIAM|Spring 2022]]<br />
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=23707SIAM Student Chapter Seminar2022-09-19T16:19:22Z<p>Nagreen: /* Fall 2022 */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 3:30 PM<br />
*'''Where:''' 9th floor lounge (we will also broadcast the virtual talks on the 9th floor lounge with refreshments)<br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
==Fall 2022==<br />
{| class="wikitable"<br />
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==Abstracts==<br />
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==Past Semesters==<br />
*[[Spring 2022 SIAM|Spring 2022]]<br />
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=23706SIAM Student Chapter Seminar2022-09-19T16:18:25Z<p>Nagreen: /* Past Semesters */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 3:30 PM<br />
*'''Where:''' 9th floor lounge (we will also broadcast the virtual talks on the 9th floor lounge with refreshments)<br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
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<br><br />
==Fall 2022==<br />
<br />
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<br />
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==Abstracts==<br />
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==Past Semesters==<br />
*[[Spring 2022 SIAM|Spring 2022]]<br />
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=23705SIAM Student Chapter Seminar2022-09-19T16:17:55Z<p>Nagreen: /* Spring 2022 */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 3:30 PM<br />
*'''Where:''' 9th floor lounge (we will also broadcast the virtual talks on the 9th floor lounge with refreshments)<br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
==Fall 2022==<br />
<br />
<br />
<br />
<br />
==Abstracts==<br />
<br />
<br />
==Past Semesters==<br />
*Spring 2022<br />
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=23704SIAM Student Chapter Seminar2022-09-19T16:17:34Z<p>Nagreen: </p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 3:30 PM<br />
*'''Where:''' 9th floor lounge (we will also broadcast the virtual talks on the 9th floor lounge with refreshments)<br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
==Spring 2022==<br />
<br />
<br />
<br />
<br />
==Abstracts==<br />
<br />
<br />
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==Past Semesters==<br />
*Spring 2022<br />
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Spring_2022_SIAM&diff=23703Spring 2022 SIAM2022-09-19T16:16:21Z<p>Nagreen: Created page with " ==Spring 2022== {| cellpadding="8" ! align="left" |date and time ! align="left" |location ! align="left" |speaker ! align="left" |title |- |Feb 7, 3:30-4 PM |Virtual [https:/..."</p>
<hr />
<div><br />
==Spring 2022==<br />
{| cellpadding="8"<br />
! align="left" |date and time<br />
! align="left" |location<br />
! align="left" |speaker<br />
! align="left" |title<br />
|-<br />
|Feb 7, 3:30-4 PM<br />
|Virtual [https://meet.google.com/gfs-yjbq-dmv/ (link)]<br />
|Keith Rush (Senior Software Engineer at [https://www.google.com/ Google])<br />
|''[https://wiki.math.wisc.edu/index.php/SIAM_Student_Chapter_Seminar#Feb_7,_Keith_Rush Industry talk]''<br />
|-<br />
|-<br />
|-<br />
|Feb 14, 3:30-4 PM<br />
|Virtual [https://uwmadison.zoom.us/j/91217562664?pwd=SGZOS3JGaFVGa250NXhDZlkrbWU3dz09/ (link)] Passcode: 400453<br />
|[https://www.linkedin.com/in/shawnmittal/ Shawn Mittal] (Senior Deliver Data Scientist at [https://www.microsoft.com/en-us/?ql=5/ Microsoft])<br />
|''[https://wiki.math.wisc.edu/index.php/SIAM_Student_Chapter_Seminar#Feb_14,_Shawn_Mittal Who, What, Why of Data Science in Industry]''<br />
|-<br />
|-<br />
|-<br />
|Feb 21, 3:30-4 PM<br />
|9th floor lounge<br />
|Brandon Boggess [https://www.epic.com/ (Epic)]<br />
|''[https://wiki.math.wisc.edu/index.php/SIAM_Student_Chapter_Seminar#Feb_21,_Brandon_Boggess Industry talk]''<br />
|-<br />
|-<br />
|-<br />
|Feb 28, 3:30-4 PM<br />
|9th floor lounge<br />
|[https://www.linkedin.com/in/shi-chen-98b7431a0/?originalSubdomain=cn/ Shi Chen] (UW-Madison)<br />
|''[https://wiki.math.wisc.edu/index.php/SIAM_Student_Chapter_Seminar#Feb_28,_Shi_Chen Classical limits of direct and inverse wave type problems -- a Wigner transform approach]''<br />
|-<br />
|-<br />
|-<br />
|Mar 7, 3:30-4 PM<br />
|Virtual [https://uwmadison.zoom.us/j/91217562664?pwd=SGZOS3JGaFVGa250NXhDZlkrbWU3dz09/ (link)] Passcode: 400453<br />
|Tom Edwards (Software Engineer at [https://www.google.com/ Google])<br />
|''[https://wiki.math.wisc.edu/index.php/SIAM_Student_Chapter_Seminar#Mar_7,_Tom_Edwards Industry talk]''<br />
|-<br />
|-<br />
|-<br />
|Mar 21, 3:30-4 PM<br />
|9th floor lounge<br />
|Aidan Howells (UW-Madison)<br />
|''[https://wiki.math.wisc.edu/index.php/SIAM_Student_Chapter_Seminar#Mar_21,_Aidan_Howells A Gentle Introduction to Chemical Reaction Network Theory]''<br />
|-<br />
|-<br />
|-<br />
|Apr 4, 3:30-4 PM<br />
|9th floor lounge<br />
|Eza Enkhtaivan (UW-Madison)<br />
|''[https://wiki.math.wisc.edu/index.php/SIAM_Student_Chapter_Seminar#Apr_4,_Eza_Enkhtaivan Reinforcement Learning and Markov Decision Processes]''<br />
|-<br />
|-<br />
|-<br />
|Apr 11, 3:30-4 PM<br />
|Virtual [https://uwmadison.zoom.us/j/91217562664?pwd=SGZOS3JGaFVGa250NXhDZlkrbWU3dz09/ (link)] Passcode: 400453<br />
|[https://www.linkedin.com/in/micky-soule-steinberg-5361a270/ Micky Steinberg] (Data Analyst at [https://www.principiaanalytics.com/ Principia Analytics])<br />
|''[https://wiki.math.wisc.edu/index.php/SIAM_Student_Chapter_Seminar#Apr_11,_Micky_Steinberg Industry talk]''<br />
|-<br />
|-<br />
|}<br />
==Abstracts==<br />
===Feb 7, Keith Rush===<br />
I'll talk about the kind of work I do today, the way I got here, and any insight I can give for someone hoping to pursue a similar path. I'll also discuss some of the things I've learned, and some of the advantages and disadvantages a mathematician has in the machine learning and computer science world. We'll be sure to have a freewheeling discussion and a good time :).<br />
===Feb 14, Shawn Mittal===<br />
A short snapshot of what the data science industry looks like followed by some lessons learned on what makes an effective data scientist.<br />
===Feb 21,Brandon Boggess===<br />
I will be talking about software development and the transition from academic research to enterprise engineering.<br />
===Feb 28, Shi Chen===<br />
The underlying physics of the same system is different when the system is described at different scales. In classical mechanics, the motion of a particle is governed by the Newton's second law, while in quantum mechanics the status of a particle follows the Schrödinger equation. The classical mechanics and the quantum mechanics are two sides of the same coin, but how can we formally connect the two disparate systems? In this talk, I will introduce the Wigner transform, which is the only known method that seamlessly connects the classical and quantum systems as the Planck constant vanishes. I will keep everything basic and briefly introduce some applications of the Wigner transform to direct and inverse wave type problems.<br />
===Mar 7, Tom Edwards===<br />
I will talk about comparisons between small and big companies.<br />
===Mar 14, Aidan Howells===<br />
We'll learn what a chemical reaction network is, with a bunch of real-world examples. There are a number of ways to model these networks as objects of mathematical study, two of which will be discussed. We'll end with a few of the questions mathematicians try to answer about these models, to give you some of the flavor of the field.<br />
===Apr 4, Eza Enkhtaivan===<br />
In recent years, Reinforcement Learning has found great success in many areas of AI research ranging from research on self-driving cars to achieving superhuman level performance in MOBA games such as Dota 2, Starcraft (Open AI) or Chess and Go (AlphaGo Zero). I will talk about the mathematical framework of Reinforcement Learning and also briefly about its applications in computational neuroscience/psychiatry as well.<br />
===Apr 11, Micky Steinberg===<br />
I will talk about a what a typical work day looks like for me, and some advice for getting a similar job coming from academia.</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=23702SIAM Student Chapter Seminar2022-09-19T16:15:44Z<p>Nagreen: </p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 3:30 PM<br />
*'''Where:''' 9th floor lounge (we will also broadcast the virtual talks on the 9th floor lounge with refreshments)<br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*Spring 2022<br />
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Printing_from_your_laptop&diff=23632Printing from your laptop2022-09-12T15:31:42Z<p>Nagreen: change URL</p>
<hr />
<div>Please see<br />
<br />
https://kb.wisc.edu/math/search.php?cat=11330<br />
<br />
for valid instructions on how to print from your laptop.</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Colloquia/Fall2022&diff=23551Colloquia/Fall20222022-09-02T15:11:11Z<p>Nagreen: cleared page</p>
<hr />
<div>please use the main [[Colloquia]] page</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Colloquia&diff=23550Colloquia2022-09-02T15:10:22Z<p>Nagreen: pasted this semesters content</p>
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<div>__NOTOC__<br />
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==September 9 , 2022, Friday at 4pm [https://math.ou.edu/~jing/ Jing Tao] (University of Oklahoma)==<br />
(host: Dymarz, Uyanik, WIMAW)<br />
<br />
'''On surface homeomorphisms'''<br />
<br />
In the 1970s, Thurston generalized the classification of self-maps of the torus to surfaces of higher genus, thus completing the work initiated by Nielsen. This is known as the Nielsen-Thurston Classification Theorem. Over the years, many alternative proofs have been obtained, using different aspects of surface theory. In this talk, I will overview the classical theory and sketch the ideas of a new proof, one that offers new insights into the hyperbolic geometry of surfaces. This is joint work with Camille Horbez.<br />
==September 23, 2022, Friday at 4pm [https://www.pabloshmerkin.org/ Pablo Shmerkin] (University of Washington) ==<br />
(host: Guo, Seeger)<br />
==September 30, 2022, Friday at 4pm==<br />
(reserved. contact: Kent)<br />
<br />
==October 7, 2022, Friday at 4pm [https://www.daniellitt.com/ Daniel Litt] (University of Toronto)==<br />
(host: Ananth Shankar)<br />
<br />
==October 14, 2022, Friday at 4pm [https://math.sciences.ncsu.edu/people/asagema/ Andrew Sageman-Furnas] (North Carolina State)==<br />
(host: Mari-Beffa)<br />
<br />
==October 21, 2022, Friday at 4pm [https://web.ma.utexas.edu/users/ntran/ Ngoc Mai Tran] (Texas)==<br />
(host: Rodriguez)<br />
== November 7-9, 2022, [https://ai.facebook.com/people/kristin-lauter/ Kriten Lauter] (Facebook) ==<br />
Distinguished lectures<br />
<br />
(host: Yang).<br />
== November 11, 2022, Friday at 4pm [http://users.cms.caltech.edu/~jtropp/ Joel Tropp] (Caltech)==<br />
This is the Annual LAA lecture. See [https://math.wisc.edu/laa-lecture/ this] for its history.<br />
<br />
(host: Qin, Jordan)<br />
==November 18, 2022, Friday at 4pm [TBD]==<br />
(reserved by HC. contact: Stechmann)<br />
==December 2, 2022, Friday at 4pm [TBD]==<br />
(reserved by HC. contact: Stechmann)<br />
==December 9, 2022, Friday at 4pm [TBD]==<br />
(reserved by HC. contact: Stechmann)<br />
== Future Colloquia ==<br />
<br />
[[Colloquia/Fall2022|Fall 2022]]<br />
<br />
[[Colloquia/Spring2023|Spring 2023]]<br />
<br />
== Past Colloquia ==<br />
[[Spring 2022 Colloquiums|Spring 2022]]<br />
<br />
[[Colloquia/Fall2021|Fall 2021]]<br />
<br />
[[Colloquia/Spring2021|Spring 2021]]<br />
<br />
[[Colloquia/Fall2020|Fall 2020]]<br />
<br />
[[Colloquia/Spring2020|Spring 2020]]<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]<br />
<br />
[[WIMAW]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Spring_2022_Colloquiums&diff=23549Spring 2022 Colloquiums2022-09-02T15:08:48Z<p>Nagreen: pasted content from Spring 2022, on 9/2/2022</p>
<hr />
<div><br />
<br />
<b>UW Madison mathematics Colloquium is on Fridays at 4:00 pm. </b><!--- in Van Vleck B239, '''unless otherwise indicated'''. ---> <br />
<br />
==January 10, 2022, Monday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://www.stat.berkeley.edu/~gheissari/ Reza Gheissari] (UC Berkeley)==<br />
(reserved by the hiring committee)<br />
<br />
'''Surface phenomena in the 2D and 3D Ising model'''<br />
<br />
Since its introduction in 1920, the Ising model has been one of the most studied models of phase transitions in statistical physics. In its low-temperature regime, the model has two thermodynamically stable phases, which, when in contact with each other, form an interface: a random curve in 2D and a random surface in 3D. In this talk, I will survey the rich phenomenology of this interface in 2D and 3D, and describe recent progress in understanding its geometry in various parameter regimes where different surface phenomena and universality classes emerge.<br />
==January 17, 2022, Monday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://sites.google.com/view/lovingmath/home Marissa Loving] (Georgia Tech)==<br />
(reserved by the hiring committee)<br />
<br />
'''Symmetries of surfaces: big and small'''<br />
<br />
We will introduce both finite and infinite-type surfaces and study their collections of symmetries, known as mapping class groups. The study of the mapping class group of finite-type surfaces has played a central role in low-dimensional topology stretching back a hundred years to work of Max Dehn and Jakob Nielsen, and gaining momentum and significance through the celebrated work of Bill Thurston on the geometry of 3-manifolds. In comparison, the study of the mapping class group of infinite-type surfaces has exploded only within the past few years. Nevertheless, infinite-type surfaces appear quite regularly in the wilds of mathematics with connections to dynamics, the topology of 3-manifolds, and even descriptive set theory -- there is a great deal of rich mathematics to be gained in their study! In this talk, we will discuss the way that the study of surfaces intersects and interacts with geometry, algebra, and number theory, as well as some of my own contributions to this vibrant area of study.<br />
==January 21, 2022, Friday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://web.math.princeton.edu/~nfm2/ Nicholas Marshall] (Princeton)==<br />
(reserved by the hiring committee)<br />
<br />
'''Laplacian quadratic forms, function regularity, graphs, and optimal transport'''<br />
<br />
In this talk, I will discuss two different applications of harmonic analysis to problems motivated by data science. Both problems involve using Laplacian quadratic forms to measure the regularity of functions. In both cases the key idea is to understand how to modify these quadratic forms to achieve a specific goal. First, in the graph setting, we suppose that a collection of m graphs G_1 = (V,E_1),...,G_m=(V,E_m) on a common set of vertices V is given, and consider the problem of finding the 'smoothest' function f : V -> R with respect to all graphs simultaneously, where the notion of smoothness is defined using graph Laplacian quadratic forms. Second, on the unit square [0,1]^2, we consider the problem of efficiently computing linearizations of 2-Wasserstein distance; here, the solution involves quadratic forms of a Witten Laplacian.<br />
==January 24, 2022, Monday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://sites.google.com/view/skippermath Rachel Skipper] (Ohio State)==<br />
(reserved by the hiring committee)<br />
<br />
'''From simple groups to symmetries of surfaces'''<br />
<br />
We will take a tour through some families of groups of historic importance in geometric group theory, including self-similar groups and Thompson’s groups. We will discuss the rich, continually developing theory of these groups which act as symmetries of the Cantor space, and how they can be used to understand the variety of infinite simple groups. Finally, we will discuss how these groups are serving an important role in the newly developing field of big mapping class groups which are used to describe symmetries of surfaces.<br />
==February 11, 2022, at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://people.math.wisc.edu/~msoskova/ Mariya Soskova] (UW-Madison)==<br />
'''The e-verse'''<br />
<br />
Computability theory studies the relative algorithmic complexity of sets of natural numbers and other mathematical objects. Turing reducibility and the induced partial order of the Turing degrees serve as the well-established model of relative computability. Enumeration reducibility captures another natural relationship between sets of natural numbers in which positive information about the first set is used to produce positive information about the second set. The induced structure of the enumeration degrees can be viewed as an extension of the Turing degrees, as there is a natural way to embed the second partial order in the first. In certain cases, the enumeration degrees can be used to capture the algorithmic content of mathematical objects, while the Turing degrees fail. Certain open problems in degree theory present as more approachable in the extended context of the enumeration degrees, e.g. first order definability. We have been working to develop a richer “e-verse”: a system of classes of enumeration degrees with interesting properties and relationships, in order to better understand the enumeration degrees. I will outline several research directions in this context.<br />
==February 18, 2022, at 4pm in B239 + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Video over Zoom], [https://people.math.wisc.edu/~seeger/ Andreas Seeger] (UW-Madison)==<br />
'''Spherical maximal functions and fractal dimensions of dilation sets'''<br />
<br />
We survey old and new problems and results on spherical means, regarding pointwise convergence, $L^p$ improving and consequences for sparse domination.<br />
==February 25, 2022, at 4pm in B239 + [http://go.wisc.edu/wuas48 Live Stream], [https://sites.google.com/view/rohini-ramadas/home Rohini Ramadas] (Warwick)==<br />
(hosted by WIMAW)<br />
<br />
'''Dynamics on the moduli space of point-configurations on the Riemann sphere'''<br />
<br />
A degree-$d$ rational function $f(z)$ in one variable with complex coefficients defines a holomorphic self-map of the Riemann sphere. A rational function is called post-critically finite (PCF) if every critical point is (pre)-periodic. PCF rational functions have been central in complex dynamics, due to their special dynamical behavior, and their special distribution within the parameter space of all rational maps.<br />
<br />
By work of Koch building on a result of Thurston, every PCF map arises as an isolated fixed point of an algebraic dynamical system on the moduli space $M_{0,n}$ of point-configurations on the Riemann sphere. I will introduce PCF maps and $M_{0,n}$. I will then present results characterizing the ensuing dynamics on $M_{0,n}$.<br />
<br />
This talk includes joint work with Nguyen-Bac Dang, Sarah Koch, David Speyer, and Rob Silversmith.<br />
==March 1, 2 and 4, 2022 (Tuesday, Wednesday and Friday), [http://www.math.stonybrook.edu/~roblaz/ Robert Lazarsfeld] (Stony Brook)==<br />
(''Departmental Distinguished Lecture series'')<br />
<br />
'''Public Lecture: Pythagorean triples and parametrized curves'''<br />
<br />
''Tuesday, March 1, 4:00pm (Humanities 3650 + [http://go.wisc.edu/n6986j Live Stream]). Note unusual time and location!''<br />
<br />
In this lecture, aimed at advanced undergraduate and beginning graduate students, I will discuss the question of when a curve in the plane admits a parameterization by polynomials or rational functions.<br />
<br />
<br />
'''Colloquium: How irrational is an irrational variety?'''<br />
<br />
''Wednesday, March 2, 4:00pm (VV B239 + [http://go.wisc.edu/wuas48 Live Stream]).''<br />
<br />
Recall that an algebraic variety is said to be rational if it has a Zariski open subset that is isomorphic to an open subset of projective space. There has been a great deal of recent activity and progress on questions of rationality, but most varieties aren't rational. I will survey a body of work concerned with measuring and controlling “how irrational” a given variety might be.<br />
<br />
<br />
'''Seminar: Measures of association for algebraic varieties'''<br />
<br />
''Friday, March 4, 4:00pm (VV B239 )''<br />
<br />
I will discuss some recent work with Olivier Martin that attempts to quantify how far two varieties are from being birationally isomorphic. Besides presenting a few results, I will discuss many open problems and avenues for further investigation.<br />
==March 11, 2022, [https://people.math.wisc.edu/~anderson/ David Anderson] (UW-Madison)==<br />
'''Stochastic models of reaction networks and the Chemical Recurrence Conjecture'''<br />
<br />
Cellular, chemical, and population processes are all often represented via networks that describe the interactions between the different population types (typically called the ''species'').<br />
<br />
If the counts of the species are low, then these systems are most often modeled as continuous-time Markov chains on $Z^d$ (with d being the number of species), with rates determined by stochastic mass-action kinetics. A natural (broad) question is: how do the qualitative properties of the dynamical system relate to the properties of the network? One specific conjecture, called the Chemical Recurrence Conjecture, and that has been open for decades, is the following: if each connected component of the network is strongly connected, then the associated stochastic model is positive recurrent (meaning the model is quite stable).<br />
<br />
I will give a general introduction to this class of models and will present the latest work towards a proof of the Chemical Recurrence Conjecture. I will make this talk accessible to graduate students, regardless of their field of study. Some of the new results presented are joint with Daniele Cappelletti, Andrea Agazzi, and Jonathan Mattingly.<br />
==March 25, 2022, Friday at 4pm on [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Zoom]. [http://www.math.lsa.umich.edu/~canary/ Richard Canary] (Michigan)==<br />
(hosted by Zimmer)<br />
<br />
'''Hitchin representations of Fuchsian groups'''<br />
<br />
Abstract: The Teichm&uuml;ller space $\mathcal T(S)$ of all hyperbolic structures on a fixed closed surface $S$ is a central object in geometry, topology and dynamics. It may be viewed as the orbifold universal cover of the moduli space of algebraic curves of fixed genus and also as a component of the space of (conjugacy classes of) representations of $\pi_1(S)$ into $\mathsf{PSL}(2,\mathbb R)$ which is topologically a cell. Hitchin discovered a component $\mathcal H_d(S)$ of the space of (conjugacy classes of) representations of $\pi_1(S)$ into $\mathsf{PSL}(d,\mathbb R)$ which is topologically a cell. Subsequently, many striking analogies between the Hitchin component $\mathcal H_d(S)$ and Teichm&uuml;ller space $\mathcal T(S)$ were found. For example, Labourie showed that all representations in $\mathcal H_d(S)$ are discrete, faithful quasi-isometric embeddings.<br />
<br />
In this talk, we will begin by gently reviewing the parallel theories of Teichm&uuml;ller space and the Hitchin component. We will finish by reviewing a long term project to develop a geometric theory of the augmented Hitchin component which parallels the classical theory of the augmented Hitchin component (which one may view as the "orbifold universal cover" of the Deligne-Mumford compactification of Teichm&uuml;ller space). This program includes joint work with Harry Bray, Nyima Kao, Giuseppe Martone, Tengren Zhang and Andy Zimmer.<br />
==April 1, 2022, Friday at 4pm in B239 + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Zoom broadcast], [https://www.patelp.com/ Priyam Patel] (Utah)==<br />
(hosted by WIMAW)<br />
<br />
'''Infinite-type surfaces'''<br />
<br />
Surfaces fall into two categories: finite-type and infinite-type. The theory of infinite-type surfaces has been historically less developed than that of finite-type surfaces, but in the last few years, there has been a surge of interest in surfaces of infinite type and their mapping class groups (informally thought of as the groups of topological symmetries of these surfaces). In this talk, I will survey some of the biggest open problems in this quickly growing subfield of geometric group theory and topology, and discuss some of my own recent joint work towards resolving them.<br />
==April 8, 2022, Friday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream], [https://math.temple.edu/~tuf27009/index.html Matthew Stover] (Temple University)==<br />
(hosted by Zimmer)<br />
<br />
'''A geometric characterization of arithmeticity'''<br />
<br />
An old, fundamental problem is classifying closed n-manifolds admitting a metric of constant curvature. The most mysterious case is constant curvature -1, that is, hyperbolic manifolds, and these divide further into "arithmetic" and "nonarithmetic" manifolds. However, it is not at all evident from the definitions that this distinction has anything to do with the differential geometry of the manifold. Uri Bader, David Fisher, Nicholas Miller and I gave a geometric characterization of arithmeticity in terms of properly immersed totally geodesic submanifolds, answering a question due independently to Alan Reid and Curtis McMullen. I will give an overview, assuming only basic differential topology, of how (non)arithmeticity and totally geodesic submanifolds are connected, then describe how this allows us to import tools from ergodic theory and homogeneous dynamics originating in groundbreaking work of Margulis to prove our characterization. Given time, I will mention some more recent developments and open questions.<br />
==April 15, 2022, Friday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream], [https://www.qatar.tamu.edu/programs/science/faculty-and-staff/berhand-lamel Bernhard Lamel], (Texas A&M University at Qatar)==<br />
(hosted by Gong)<br />
<br />
'''Convergence and Divergence of Formal Power Series Maps'''<br />
<br />
Consider two real-analytic hypersurfaces (i.e. defined by convergent power series) in complex spaces. A formal holomorphic map is said to take one into the other if the composition of the power series defining the target with the map (which is just another formal power series) is a (formal) multiple of the defining power series of the source. In this talk, we are going to be interested in conditions for formal holomorphic maps to necessarily be convergent. Now, a formal holomorphic map taking the real line to itself is just a formal power series with real coefficients; this example also gives rise to real hypersurfaces in higher dimensional complex spaces having divergent formal self-maps. On the other hand, a formal map taking the unit sphere in higher dimensional complex space to itself is necessarily a rational map with poles outside of the sphere, in particular, the formal power series defining it converges. The convergence theory for formal self-maps of real hypersurfaces has been developed in the late 1990s and early 2000s. For formal embeddings, “ideal" conditions had been long conjectured. I’m going to give an introduction to this problem and talk about some joint work from 2018 with Nordine Mir giving a basically complete answer to the question when a formal map taking a real-analytic hypersurface in complex space into another one is necessarily convergent.<br />
==April 25-26-27 (Monday [VV B239], Tuesday [Chamberlin 2241], Wednesday [VV B239]) 4 pm [https://math.mit.edu/directory/profile.php?pid=1461 Larry Guth] (MIT)==<br />
(''Departmental Distinguished Lecture series'')<br />
<br />
'''Reflections on decoupling and Vinogradov's mean value problem.'''<br />
<br />
Decoupling is a recent development in Fourier analysis that has solved several longstanding problems. The goal of the lectures is to describe this development to a general mathematical audience.<br />
<br />
We will focus on one particular application of decoupling: Vinogradov's mean value problem from analytic number theory. This problem is about the number of solutions of a certain system of diophantine equations. It was raised in the 1930s and resolved in the last decade.<br />
<br />
We will give some context about this problem, but the main goal of the lectures is to explore the ideas that go into the proof. The method of decoupling came as a big surprise to me, and I think to other people working in the field. The main idea in the proof of decoupling is to combine estimates from many different scales. We will describe this process and reflect on why it is helpful.<br />
<br />
'''Lecture 1:'''Introduction to decoupling and Vinogradov's mean value problem. [http://go.wisc.edu/wuas48 Live stream]<br />
In this lecture, we introduce Vinogradov's problem and give an overview of the proof.<br />
'''Lecture 2:''' Features of the proof of decoupling.<br />
In this lecture, we look more closely at some features of the proof of decoupling. The first feature we examine is the exact form of writing the inequality, which is especially suited for doing induction and connecting information from different scales. The second feature we examine is called the wave packet decomposition. This structure has roots in quantum physics and in information theory.<br />
'''Lecture 3:''' Open problems.<br />
In this lecture, we discuss some open problems in number theory that look superficially similar to Vinogradov mean value conjecture, such as Hardy and Littlewood's Hypothesis K*. In this lecture, we probe the limitations of decoupling by exploring why the techniques from the first two lectures don't work on these open problems. Hopefully this will give a sense of some of the issues and difficulties involved in these problems.<br />
==May 10+12, 2022, Tuesday+Thursday, 12pm on [https://go.wisc.edu/d456cn Zoom]. [http://www.ma.huji.ac.il/~kalai/ Gil Kalai] (Hebrew University)==<br />
(''Hilldale Lectures / Special colloquium'')<br />
<br />
'''The argument against quantum computers'''<br />
<br />
In the first lecture I will introduce quantum computers and present an argument for why quantum computers are impossible. From my analysis I will derive general principles for the behavior of noisy quantum systems and will also briefly discuss the recent announcements concerning "quantum computational supremacy,” which conflict with my theory. In the second lecture I will discuss the connection between the possibility of quantum computers, the predictability of complex quantum systems in nature, and the issue of free will. Both lectures are self-contained, intended for a wide audience and assume no background on quantum computers or philosophy.<br />
<br />
<br />
'''Lecture I:''' The Argument Against Quantum Computers<br />
<br />
A quantum computer is a new type of computer based on quantum physics. When it comes to certain computational objectives, the computational ability of quantum computers is tens, and even hundreds of orders of magnitude faster than that of the familiar digital computers, and their construction will enable us to factor large numbers and to break most of the current cryptosystems.<br />
<br />
We will describe a computational complexity argument against the feasibility of quantum computers. We identify a very low complexity class of probability distributions described by noisy intermediate-scale quantum computers (NISQ computers), and explain why it will allow neither good-quality quantum error-correction nor a demonstration of "quantum supremacy."<br />
<br />
The analysis also shows that for a wide range of noise rates NISQ computers are inherently chaotic in the strong sense that their output cannot be predicted even probabilistically. Some general principles governing the behavior of noisy quantum systems in a "world devoid of quantum computers" will be derived.<br />
<br />
I will briefly discuss the recent announcements regarding "quantum computational supremacy" by scientists from Google ("Sycamore") and from USTC, which conflict with my theory.<br />
<br />
The lecture is going to be self-contained, it is intended for a wide audience, and we assume no prior knowledge of quantum computers.<br />
<br />
Relevant papers are: https://arxiv.org/abs/1908.02499 https://arxiv.org/abs/2008.05188 https://arxiv.org/abs/1409.3093 https://arxiv.org/abs/2008.05177<br />
<br />
<br />
'''Lecture II:''' Quantum Computers, Predictability and Free Will<br />
<br />
We will discuss the connection between the possibility of quantum computers, the predictability of complex quantum systems in nature, and the issue of free will. The argument regarding the impossibility of quantum computers implies that the future of complex quantum systems in nature cannot be predicted. A more involved argument shows that the impossibility of quantum computation supports the view whereby the laws of nature do not in fact contradict free will. For this philosophical journey, we discuss in parallel the Google “Sycamore” quantum computer of 12 computational units (qubits), and the human- being Alice, whose free will we attempt to analyze.<br />
<br />
At the center of the argument is the ambiguity inherent in the way the future is determined by the past; ambiguity that is not expressed in terms of the mathematical laws of physics (which are fully deterministic) but rather in terms of the physical description of the objects we refer to.<br />
<br />
The lecture will be self-contained and we will not assume prior background regarding quantum computers or philosophy. (It will also not rely on the first lecture.)<br />
<br />
A relevant paper is: https://arxiv.org/abs/2204.02768</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Colloquia&diff=23548Colloquia2022-09-02T15:08:19Z<p>Nagreen: added link to historical semesters</p>
<hr />
<div>__NOTOC__<br />
<br />
<br />
<b>UW Madison mathematics Colloquium is on Fridays at 4:00 pm. </b><br />
<br />
<!--- in Van Vleck B239, '''unless otherwise indicated'''. ---><br />
<br />
<br />
== January 10, 2022, Monday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://www.stat.berkeley.edu/~gheissari/ Reza Gheissari] (UC Berkeley) ==<br />
<br />
(reserved by the hiring committee)<br />
<br />
'''Surface phenomena in the 2D and 3D Ising model'''<br />
<br />
Since its introduction in 1920, the Ising model has been one of the most studied models of phase transitions in statistical physics. In its low-temperature regime, the model has two thermodynamically stable phases, which, when in contact with each other, form an interface: a random curve in 2D and a random surface in 3D. In this talk, I will survey the rich phenomenology of this interface in 2D and 3D, and describe recent progress in understanding its geometry in various parameter regimes where different surface phenomena and universality classes emerge.<br />
<br />
== January 17, 2022, Monday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://sites.google.com/view/lovingmath/home Marissa Loving] (Georgia Tech) ==<br />
<br />
(reserved by the hiring committee)<br />
<br />
'''Symmetries of surfaces: big and small'''<br />
<br />
We will introduce both finite and infinite-type surfaces and study their collections of symmetries, known as mapping class groups. The study of the mapping class group of finite-type surfaces has played a central role in low-dimensional topology stretching back a hundred years to work of Max Dehn and Jakob Nielsen, and gaining momentum and significance through the celebrated work of Bill Thurston on the geometry of 3-manifolds. In comparison, the study of the mapping class group of infinite-type surfaces has exploded only within the past few years. Nevertheless, infinite-type surfaces appear quite regularly in the wilds of mathematics with connections to dynamics, the topology of 3-manifolds, and even descriptive set theory -- there is a great deal of rich mathematics to be gained in their study! In this talk, we will discuss the way that the study of surfaces intersects and interacts with geometry, algebra, and number theory, as well as some of my own contributions to this vibrant area of study.<br />
<br />
== January 21, 2022, Friday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://web.math.princeton.edu/~nfm2/ Nicholas Marshall] (Princeton) ==<br />
<br />
(reserved by the hiring committee)<br />
<br />
'''Laplacian quadratic forms, function regularity, graphs, and optimal transport'''<br />
<br />
In this talk, I will discuss two different applications of harmonic analysis to<br />
problems motivated by data science. Both problems involve using Laplacian<br />
quadratic forms to measure the regularity of functions. In both cases the key<br />
idea is to understand how to modify these quadratic forms to achieve a specific<br />
goal. First, in the graph setting, we suppose that a collection of m graphs<br />
G_1 = (V,E_1),...,G_m=(V,E_m) on a common set of vertices V is given,<br />
and consider the problem of finding the 'smoothest' function f : V -> R with<br />
respect to all graphs simultaneously, where the notion of smoothness is defined<br />
using graph Laplacian quadratic forms. Second, on the unit square [0,1]^2, we<br />
consider the problem of efficiently computing linearizations of 2-Wasserstein<br />
distance; here, the solution involves quadratic forms of a Witten Laplacian.<br />
<br />
== January 24, 2022, Monday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://sites.google.com/view/skippermath Rachel Skipper] (Ohio State) ==<br />
<br />
(reserved by the hiring committee)<br />
<br />
'''From simple groups to symmetries of surfaces'''<br />
<br />
We will take a tour through some families of groups of historic importance in geometric group theory, including self-similar groups and Thompson’s groups. We will discuss the rich, continually developing theory of these groups which act as symmetries of the Cantor space, and how they can be used to understand the variety of infinite simple groups. Finally, we will discuss how these groups are serving an important role in the newly developing field of big mapping class groups which are used to describe symmetries of surfaces.<br />
<br />
== February 11, 2022, at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream] + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Chat over Zoom], [https://people.math.wisc.edu/~msoskova/ Mariya Soskova] (UW-Madison) ==<br />
<br />
'''The e-verse'''<br />
<br />
Computability theory studies the relative algorithmic complexity of sets of natural numbers and other mathematical objects. Turing reducibility and the induced partial order of the Turing degrees serve as the well-established model of relative computability. Enumeration reducibility captures another natural relationship between sets of natural numbers in which positive information about the first set is used to produce positive information about the second set. The induced structure of the enumeration degrees can be viewed as an extension of the Turing degrees, as there is a natural way to embed the second partial order in the first. In certain cases, the enumeration degrees can be used to capture the algorithmic content of mathematical objects, while the Turing degrees fail. Certain open problems in degree theory present as more approachable in the extended context of the enumeration degrees, e.g. first order definability. We have been working to develop a richer “e-verse”: a system of classes of enumeration degrees with interesting properties and relationships, in order to better understand the enumeration degrees. I will outline several research directions in this context.<br />
<br />
== February 18, 2022, at 4pm in B239 + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Video over Zoom], [https://people.math.wisc.edu/~seeger/ Andreas Seeger] (UW-Madison) ==<br />
<br />
'''Spherical maximal functions and fractal dimensions of dilation sets'''<br />
<br />
We survey old and new problems and results on spherical means, regarding pointwise convergence, $L^p$ improving and consequences for sparse domination.<br />
<br />
== February 25, 2022, at 4pm in B239 + [http://go.wisc.edu/wuas48 Live Stream], [https://sites.google.com/view/rohini-ramadas/home Rohini Ramadas] (Warwick) == <br />
<br />
(hosted by WIMAW)<br />
<br />
'''Dynamics on the moduli space of point-configurations on the Riemann sphere'''<br />
<br />
A degree-$d$ rational function $f(z)$ in one variable with complex coefficients defines a holomorphic self-map of the Riemann sphere. A rational function is called post-critically finite (PCF) if every critical point is (pre)-periodic. PCF rational functions have been central in complex dynamics, due to their special dynamical behavior, and their special distribution within the parameter space of all rational maps. <br />
<br />
By work of Koch building on a result of Thurston, every PCF map arises as an isolated fixed point of an algebraic dynamical system on the moduli space $M_{0,n}$ of point-configurations on the Riemann sphere. I will introduce PCF maps and $M_{0,n}$. I will then present results characterizing the ensuing dynamics on $M_{0,n}$. <br />
<br />
This talk includes joint work with Nguyen-Bac Dang, Sarah Koch, David Speyer, and Rob Silversmith.<br />
<br />
== March 1, 2 and 4, 2022 (Tuesday, Wednesday and Friday), [http://www.math.stonybrook.edu/~roblaz/ Robert Lazarsfeld] (Stony Brook) ==<br />
(''Departmental Distinguished Lecture series'')<br />
<br />
'''Public Lecture: Pythagorean triples and parametrized curves'''<br />
<br />
''Tuesday, March 1, 4:00pm (Humanities 3650 + [http://go.wisc.edu/n6986j Live Stream]). Note unusual time and location!''<br />
<br />
In this lecture, aimed at advanced undergraduate and beginning graduate students, I will discuss the question of when a curve in the plane admits a parameterization by polynomials or rational functions. <br />
<br />
<br />
'''Colloquium: How irrational is an irrational variety?'''<br />
<br />
''Wednesday, March 2, 4:00pm (VV B239 + [http://go.wisc.edu/wuas48 Live Stream]).''<br />
<br />
Recall that an algebraic variety is said to be rational if it has a Zariski open subset that is isomorphic to an open subset of projective space. There has been a great deal of recent activity and progress on questions of rationality, but most varieties aren't rational. I will survey a body of work concerned with measuring and controlling “how irrational” a given variety might be.<br />
<br />
<br />
'''Seminar: Measures of association for algebraic varieties'''<br />
<br />
''Friday, March 4, 4:00pm (VV B239 )''<br />
<br />
I will discuss some recent work with Olivier Martin that attempts to quantify how far two varieties are from being birationally isomorphic. Besides presenting a few results, I will discuss many open problems and avenues for further investigation.<br />
<br />
== March 11, 2022, [https://people.math.wisc.edu/~anderson/ David Anderson] (UW-Madison) ==<br />
<br />
'''Stochastic models of reaction networks and the Chemical Recurrence Conjecture'''<br />
<br />
Cellular, chemical, and population processes are all often represented via networks that describe the interactions between the different population types (typically called the ''species''). <br />
<br />
If the counts of the species are low, then these systems are most often modeled as continuous-time Markov chains on $Z^d$ (with d being the number of species), with rates determined by stochastic mass-action kinetics. A natural (broad) question is: how do the qualitative properties of the dynamical system relate to the properties of the network? One specific conjecture, called the Chemical Recurrence Conjecture, and that has been open for decades, is the following: if each connected component of the network is strongly connected, then the associated stochastic model is positive recurrent (meaning the model is quite stable). <br />
<br />
I will give a general introduction to this class of models and will present the latest work towards a proof of the Chemical Recurrence Conjecture. I will make this talk accessible to graduate students, regardless of their field of study. Some of the new results presented are joint with Daniele Cappelletti, Andrea Agazzi, and Jonathan Mattingly.<br />
<br />
== March 25, 2022, Friday at 4pm on [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Zoom]. [http://www.math.lsa.umich.edu/~canary/ Richard Canary] (Michigan) ==<br />
<br />
(hosted by Zimmer)<br />
<br />
'''Hitchin representations of Fuchsian groups'''<br />
<br />
Abstract: The Teichm&uuml;ller space $\mathcal T(S)$ of all hyperbolic structures on a fixed closed surface $S$ is a central object in geometry, topology and dynamics. It may be viewed as the orbifold universal cover of the moduli space of algebraic curves of fixed genus and also as a component of the space of (conjugacy classes of) representations of $\pi_1(S)$ into $\mathsf{PSL}(2,\mathbb R)$ which is topologically a cell.<br />
Hitchin discovered a component $\mathcal H_d(S)$ of the space of (conjugacy classes of) representations of $\pi_1(S)$ into $\mathsf{PSL}(d,\mathbb R)$<br />
which is topologically a cell. Subsequently, many striking analogies between the Hitchin component $\mathcal H_d(S)$ and Teichm&uuml;ller space $\mathcal T(S)$ were found. For example, Labourie showed that all representations in $\mathcal H_d(S)$ are discrete, faithful quasi-isometric embeddings.<br />
<br />
In this talk, we will begin by gently reviewing the parallel theories of Teichm&uuml;ller space and the Hitchin component. We will finish by reviewing a long term project to develop a geometric theory of the augmented Hitchin component which parallels the classical theory of the augmented Hitchin component (which one may view as the "orbifold universal cover" of the Deligne-Mumford compactification of Teichm&uuml;ller space). This program includes joint work with Harry Bray, Nyima Kao, Giuseppe Martone, Tengren Zhang and Andy Zimmer.<br />
<br />
== April 1, 2022, Friday at 4pm in B239 + [https://uwmadison.zoom.us/j/93283927523?pwd=S3V6Nlh4bUhYc0F5QzNabi9RMSthUT09 Zoom broadcast], [https://www.patelp.com/ Priyam Patel] (Utah) ==<br />
<br />
(hosted by WIMAW)<br />
<br />
'''Infinite-type surfaces'''<br />
<br />
Surfaces fall into two categories: finite-type and infinite-type. The theory of infinite-type surfaces has been historically less developed than that of finite-type surfaces, but in the last few years, there has been a surge of interest in surfaces of infinite type and their mapping class groups (informally thought of as the groups of topological symmetries of these surfaces). In this talk, I will survey some of the biggest open problems in this quickly growing subfield of geometric group theory and topology, and discuss some of my own recent joint work towards resolving them.<br />
<br />
== April 8, 2022, Friday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream], [https://math.temple.edu/~tuf27009/index.html Matthew Stover] (Temple University) ==<br />
<br />
(hosted by Zimmer)<br />
<br />
'''A geometric characterization of arithmeticity'''<br />
<br />
An old, fundamental problem is classifying closed n-manifolds admitting a metric of constant curvature. The most mysterious case is constant curvature -1, that is, hyperbolic manifolds, and these divide further into "arithmetic" and "nonarithmetic" manifolds. However, it is not at all evident from the definitions that this distinction has anything to do with the differential geometry of the manifold. Uri Bader, David Fisher, Nicholas Miller and I gave a geometric characterization of arithmeticity in terms of properly immersed totally geodesic submanifolds, answering a question due independently to Alan Reid and Curtis McMullen. I will give an overview, assuming only basic differential topology, of how (non)arithmeticity and totally geodesic submanifolds are connected, then describe how this allows us to import tools from ergodic theory and homogeneous dynamics originating in groundbreaking work of Margulis to prove our characterization. Given time, I will mention some more recent developments and open questions.<br />
<br />
== April 15, 2022, Friday at 4pm in B239 + [http://go.wisc.edu/wuas48 Live stream], [https://www.qatar.tamu.edu/programs/science/faculty-and-staff/berhand-lamel Bernhard Lamel], (Texas A&M University at Qatar) ==<br />
<br />
(hosted by Gong)<br />
<br />
'''Convergence and Divergence of Formal Power Series Maps'''<br />
<br />
Consider two real-analytic hypersurfaces (i.e. defined by convergent power series) in complex spaces. A formal holomorphic map is said to take one into the other if the composition of the power series defining the target with the map (which is just another formal power series) is a (formal) multiple of the defining power series of the source. In this talk, we are going to be interested in conditions for formal holomorphic maps to necessarily be convergent. Now, a formal holomorphic map taking the real line to itself is just a formal power series with real coefficients; this example also gives rise to real hypersurfaces in higher dimensional complex spaces having divergent formal self-maps. On the other hand, a formal map taking the unit sphere in higher dimensional complex space to itself is necessarily a rational map with poles outside of the sphere, in particular, the formal power series defining it converges. The convergence theory for formal self-maps of real hypersurfaces has been developed in the late 1990s and early 2000s. For formal embeddings, “ideal" conditions had been long conjectured. I’m going to give an introduction to this problem and talk about some joint work from 2018 with Nordine Mir giving a basically complete answer to the question when a formal map taking a real-analytic hypersurface in complex space into another one is necessarily convergent.<br />
<br />
== April 25-26-27 (Monday [VV B239], Tuesday [Chamberlin 2241], Wednesday [VV B239]) 4 pm [https://math.mit.edu/directory/profile.php?pid=1461 Larry Guth] (MIT) ==<br />
<br />
(''Departmental Distinguished Lecture series'')<br />
<br />
'''Reflections on decoupling and Vinogradov's mean value problem.'''<br />
<br />
Decoupling is a recent development in Fourier analysis that has solved several longstanding problems. The goal of the lectures is to describe this development to a general mathematical audience.<br />
<br />
We will focus on one particular application of decoupling: Vinogradov's mean value problem from analytic number theory. This problem is about the number of solutions of a certain system of diophantine equations. It was raised in the 1930s and resolved in the last decade.<br />
<br />
We will give some context about this problem, but the main goal of the lectures is to explore the ideas that go into the proof. The method of decoupling came as a big surprise to me, and I think to other people working in the field. <br />
The main idea in the proof of decoupling is to combine estimates from many different scales. We will describe this process and reflect on why it is helpful.<br />
<br />
'''Lecture 1:'''Introduction to decoupling and Vinogradov's mean value problem.<br />
[http://go.wisc.edu/wuas48 Live stream]<br />
<br />
In this lecture, we introduce Vinogradov's problem and give an overview of the proof.<br />
<br />
'''Lecture 2:''' Features of the proof of decoupling.<br />
<br />
In this lecture, we look more closely at some features of the proof of decoupling. The first feature we examine is the exact form of writing the inequality, which is especially suited for doing induction and connecting information from different scales. The second feature we examine is called the wave packet decomposition. This structure has roots in quantum physics and in information theory.<br />
<br />
'''Lecture 3:''' Open problems.<br />
<br />
In this lecture, we discuss some open problems in number theory that look superficially similar to Vinogradov mean value conjecture, such as Hardy and Littlewood's Hypothesis K*. In this lecture, we probe the limitations of decoupling by exploring why the techniques from the first two lectures don't work on these open problems. Hopefully this will give a sense of some of the issues and difficulties involved in these problems.<br />
<br />
== May 10+12, 2022, Tuesday+Thursday, 12pm on [https://go.wisc.edu/d456cn Zoom]. [http://www.ma.huji.ac.il/~kalai/ Gil Kalai] (Hebrew University) ==<br />
<br />
(''Hilldale Lectures / Special colloquium'')<br />
<br />
'''The argument against quantum computers'''<br />
<br />
In the first lecture I will introduce quantum computers and present an argument for why quantum computers are impossible. From my analysis I will derive general principles for the behavior of noisy quantum systems and will also briefly discuss the recent announcements concerning "quantum computational supremacy,” which conflict with my theory. In the second lecture I will discuss the connection between the possibility of quantum computers, the predictability of complex quantum systems in nature, and the issue of free will. Both lectures are self-contained, intended for a wide audience and assume no background on quantum computers or philosophy. <br />
<br />
<br />
'''Lecture I:''' The Argument Against Quantum Computers<br />
<br />
A quantum computer is a new type of computer based on quantum physics. <br />
When it comes to certain computational objectives, the computational ability of quantum <br />
computers is tens, and even hundreds of orders of magnitude faster than that of the familiar digital computers, and their construction will enable us to factor large <br />
numbers and to break most of the current cryptosystems.<br />
<br />
We will describe a computational complexity argument against the feasibility of quantum<br />
computers. We identify a very low complexity class of probability distributions described by <br />
noisy intermediate-scale quantum computers (NISQ computers), and explain why it will<br />
allow neither good-quality quantum error-correction nor a demonstration of "quantum<br />
supremacy."<br />
<br />
The analysis also shows that for a wide range of noise rates NISQ computers are inherently<br />
chaotic in the strong sense that their output cannot be predicted even probabilistically. <br />
Some general principles governing the behavior of noisy quantum systems in a "world<br />
devoid of quantum computers" will be derived.<br />
<br />
I will briefly discuss the recent announcements regarding "quantum computational supremacy" by scientists from Google ("Sycamore") and from USTC, which conflict with my<br />
theory.<br />
<br />
The lecture is going to be self-contained, it is intended for a wide audience, and we assume<br />
no prior knowledge of quantum computers.<br />
<br />
Relevant papers are:<br />
https://arxiv.org/abs/1908.02499<br />
https://arxiv.org/abs/2008.05188<br />
https://arxiv.org/abs/1409.3093<br />
https://arxiv.org/abs/2008.05177<br />
<br />
<br />
<br />
'''Lecture II:''' Quantum Computers, Predictability and Free Will<br />
<br />
We will discuss the connection between the possibility of quantum computers, the<br />
predictability of complex quantum systems in nature, and the issue of free will.<br />
The argument regarding the impossibility of quantum computers implies that the future of<br />
complex quantum systems in nature cannot be predicted. A more involved argument shows<br />
that the impossibility of quantum computation supports the view whereby the laws of nature<br />
do not in fact contradict free will. For this philosophical journey, we discuss in parallel the<br />
Google “Sycamore” quantum computer of 12 computational units (qubits), and the human-<br />
being Alice, whose free will we attempt to analyze.<br />
<br />
At the center of the argument is the ambiguity inherent in the way the future is determined<br />
by the past; ambiguity that is not expressed in terms of the mathematical laws of physics<br />
(which are fully deterministic) but rather in terms of the physical description of the objects<br />
we refer to.<br />
<br />
The lecture will be self-contained and we will not assume prior background regarding<br />
quantum computers or philosophy. (It will also not rely on the first lecture.)<br />
<br />
A relevant paper is:<br />
https://arxiv.org/abs/2204.02768<br />
<br />
== Future Colloquia ==<br />
<br />
[[Colloquia/Fall2022|Fall 2022]]<br />
<br />
[[Colloquia/Spring2023|Spring 2023]]<br />
<br />
== Past Colloquia ==<br />
[[Spring 2022 Colloquiums|Spring 2022]]<br />
<br />
[[Colloquia/Fall2021|Fall 2021]]<br />
<br />
[[Colloquia/Spring2021|Spring 2021]]<br />
<br />
[[Colloquia/Fall2020|Fall 2020]]<br />
<br />
[[Colloquia/Spring2020|Spring 2020]]<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]<br />
<br />
[[WIMAW]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Computer_Help&diff=23300Computer Help2022-06-29T16:19:59Z<p>Nagreen: /* E-mail Web Forms */ changed forms information</p>
<hr />
<div>'''Computer Help'''<br />
This is a guide to the computer facilities, services and software available at the Math department of the University of Wisconsin. Most of the facilities are for department's the faculty, graduate students and staff. <br />
<br />
==How to report an issue==<br />
* https://go.wisc.edu/mathit<br />
<br />
== Accounts and Policies ==<br />
* [[Math Accounts]]<br />
* [[Math Computer Policies]]<br />
* [[Quotas]]<br />
* [[University Computer Policies]]<br />
* [[Math Apps]]<br />
<br />
=== Account Set Up ===<br />
Every person in the math department should be provided the opportunity to set up an account. That account is used for ...<br />
<br />
* computer login for math department computers<br />
* the ability to print to department printers<br />
* file storage on the department file server<br />
* access to math department servers for math software<br />
* the ability to login to various department web pages<br />
<br />
This is different from your WiscMail account, which is used for <br />
<br />
* payroll<br />
* access to Canvas<br />
* access to UW system level IT resources such as Google Apps and UWNet wireless<br />
* your UW wiscmail account<br />
* login to various UW protected webpages hosted throughout the university<br />
* WiscVPN<br />
<br />
==== Changing your Math Dept. Account Password ====<br />
You can reset or change your account password any time:<br />
# Go to [https://web.math.wisc.edu/help/ https://web.math.wisc.edu/help/]<br />
# Click "Forgot Password"<br />
# Click the link you will receive in your email.<br />
<br />
=== Dealing With Spam ===<br />
<br />
The University runs Office 365, which has some spam controls built in. <br />
<br />
There's two parts to the UW's spam control.<br />
<br />
* [https://kb.wisc.edu/page.php?id=53321 The Clutter Folder]<br />
* [https://kb.wisc.edu/page.php?id=45051 The Junk Mail folder]<br />
<br />
Questions regarding these two methods should be directed to the DoIT Help Desk. (264-HELP, 4357)<br />
<br />
=== Vacation Mail ===<br />
<br />
[https://kb.wisc.edu/page.php?id=32606 How to set up an auto-reply.] <br />
<br />
=== Forwarding your e-mail ===<br />
<br />
[https://kb.wisc.edu/page.php?id=36539 Set/Manage a Forward on a NetID or Service Account]<br />
<br />
=== Leaving the Department ===<br />
If you leave the Math Department, we will occasionally remove old accounts. In some cases, we can leave an account in place for <br />
<br />
#) users that are continuing to collaborate with faculty or staff for research<br />
#) users that wish to continue to receive mail under their math account for a time. <br />
<br />
While we can't guarantee infinite continuation of your email account because that is controlled by DoIT, we do have some methods at our command to make this more streamlined and less prone to being deactivated.<br />
<br />
Generally, we remove accounts in October and March. In most cases, you'll be told in an email that we intend on doing this.<br />
<br />
If you feel you fall under either of the two case scenarios listed above, please email nagreen@math.wisc.edu.<br />
<br />
=== E-mail Web Forms ===<br />
<br />
If you need to have someone contact you via your website, it is better to use a Google Form. <br />
<br />
https://kb.wisc.edu/104251 has information for creating a google form for use in a class, but you can adapt those instructions to create forms for almost any use case. The responses are collected in Google, but you can set up a notification to send you an email when you receive a response.<br />
<br />
== Facilities ==<br />
<br />
The facilities and equipment described below are for use by UW Math department faculty and graduate students on the UW Madison Campus and, preferably, in Van Vleck hall.<br />
<br />
===Mobile Computers and Projectors===<br />
Instructors may borrow laptop computers and projectors for demonstrations in any Van Vleck classroom. This equipment is kept in the AMP Library in Chamberlin Hall. You may check them out for up to 4 hours using your UW ID card. The math library also has an assortment of VGA and HDMI video cables which can be used to connect a PC, Macintosh computer or iPad to a projector. One of the projectors has built in speakers and a DVD player. It also has two microphones which can be connected to it. WARNING: the laptops available for check out are somewhat old and have only basic software (MS Office, TeX) on them. It is far better to use your own computer with the Department's projectors.<br />
<br />
===Ceiling Mounted Projectors===<br />
<br />
Classrooms B102, B107, B130, B215, B231 and B223, B239, the 901 seminar room, and the 911 Lounge each have a ceiling mounted projector. These projectors provide better displays than the mobile units. They can be used with a laptop computer. If you want to reserve one of these rooms, contact Sharon Paulson at paulson@math.wisc.edu. Keep in mind, though, that they're heavily booked and usually only available at the beginning or end of the day.<br />
<br />
The Math Department's computer staff maintain the projectors in 901 and 911. All the others are maintained by the UW Physical Plant. Please contact Derek Dombrowski about them. You will need an access code to use them and a key if you want to use the document camera or microphone with them.<br />
Here is Derek's contact information:<br />
Derek Dombrowski<br />
373A BASCOM HALL<br />
ddombrowski@fpm.wisc.edu<br />
(608) 265-9697<br />
(608) 516-5993<br />
<br />
===Scanners ===<br />
[[Scanners]]<br />
<br />
= Printing =<br />
<br />
==Math Dept Printers==<br />
{| class="wikitable"<br />
! Location<br />
! PrinterName<br />
! Printer Type<br />
|-<br />
|3rd hall<br />
|3<br />
|Ricoh IMC6000<br />
|-<br />
|4th hall<br />
|4<br />
|Ricoh IMC6000<br />
|-<br />
|5th hall<br />
|5<br />
|Ricoh IMC6000<br />
|-<br />
|6th hall<br />
|6<br />
|Ricoh IMC6000<br />
|-<br />
|7th hall<br />
|7<br />
|Ricoh IMC6000<br />
|-<br />
|8th hall<br />
|8<br />
|Ricoh IMC6000<br />
|-<br />
|101B VV<br />
|a<br />
|HP LaserJet 600 M601<br />
|}<br />
<br />
During the summer of 2020, new Ricoh IMC 6000 printers were placed on floors 3-8. We will also switched from LPRNG to CUPS (the Common Unix Printing System) on our unix print servers. <br />
<br />
As of 2014, we stopped charging for overages in printing, but want people to consider carefully the costs of consumables and paper, and the impact on the climate from overuse of paper. Please limit your use of our copiers to fewer than 250 pages a month.<br />
<br />
== Supplies ==<br />
If the printers run out of paper, please get more paper from the Copy Center on the second floor<br />
and place it in the printers. If you are unsure how to do this, ask the computer staff for assistance. For assistance with other problems (no toner, paper jams, etc. ) see Henry Mayes in 507 (for issues with the Ricoh copiers) and Sharon Paulson in 220 (for help with the printers in B127 and 101b). <br />
<br />
See the [http://www.cups.org/ cups guide] for more detailed information on printing with cups.<br />
Click on the links below to learn how to use each function with the Ricoh copiers.<br />
<br />
== Ricoh Copier ==<br />
<br />
[[Ricoh Copier FAQ]]<br />
<br />
Only people with computer accounts in the UW Math Department will be allowed to use the Van Vleck Ricoh copiers. If you have a math account, you will receive a code to use for copying. These <br />
codes will be mailed out once a year in September after old accounts are deleted and new ones added. '''NOTE''': if you forget your copier code, login to one of<br />
the math department linux PCs and type '''whatsmypin'''.<br />
<br />
* You copier code is only required for copying. Although the default display shows the copier login, you do not have to login in order to print or scan. Just push the buttons at the left to select the scanner or printer function.<br />
<br />
* Your code can be used on any of the copiers on floors 3-8. Do not use the copiers on the second floor. They are reserved for the administrative staff.<br />
<br />
* After you have finished copying, do not touch the display. Your login will time out after 60 seconds.<br />
<br />
* Everyone with a math dept account is urged to keep their printing at fewer than 250 pages a month. The Math Department does keep a count of printing totals. You may receive a report each month on your total printing. At the end of the month, these are zeroed out.<br />
<br />
* How to create a multi-page PDF document: Most people will want to create a multipage PDF scan of their document (instead of the default which is a single page TIFF document). To do this press the SCANNER button to the left of the display. Select SEND FILE TYPE/NAME in the left hand column of the display, then select MULTI-PAGE -> PDF<br />
<br />
== Ricoh Printing FAQ ==<br />
* [[Ricoh Printing FAQ]]<br />
* [[Using the Ricoh with Linux]] (command line printing)<br />
* [[Using a Ricoh Printer on a Macintosh]]<br />
* [[Using a Ricoh Printer on a PC]]<br />
* [[Troubleshooting]]<br />
<br />
== Ricoh Scanner FAQ ==<br />
[[Ricoh Scanner FAQ]]<br />
<br />
= Remote Access =<br />
<br />
[https://www.math.wisc.edu/wiki/index.php/Accessing_your_Math_department_network_space | Using ssh, sftp, and Sshfs]<br />
<br />
= TeX/LaTeX =<br />
TeX and LaTeX are supported on the Math Department computers. To learn more about<br />
Typesetting with LaTeX we recommend the following [http://www.latex-project.org/guides/books.html site]. Mediawiki has some support for LaTeX<br />
as the following example shows:<br />
<br />
<math><br />
\int_{[0, 1]^n} <br />
\left| \sum_{k = 1}^n \mathrm{e}^{2 \pi \mathrm{i} \, x_k} \right|^s \mathrm{d}\boldsymbol{x}<br />
</math><br />
<br />
= Unix =<br />
<br />
==Manipulating PDF files ==<br />
<br />
The ''pdftk'' toolkit provides several useful tools for manipulating PDF files without using<br />
Adobe Acrobat Pro. Here are some examples:<br />
<br />
1. This command will split off the first 15 pages of the file NSFProposal.pdf and save it to 'front.pdf'. Substituting 'cat 16-end' for 'cat 1-15' will save the second half of the file.<br />
<br />
pdftk NSFProposal.pdf cat 1-15 output front.pdf<br />
<br />
2. This command will merge two (or more) pdf files:<br />
<br />
pdftk 1.pdf 2.pdf 3.pdf cat output 123.pdf<br />
<br />
You can find more examples at [http://www.pdflabs.com/docs/pdftk-cli-examples/ pdftk-examples]<br />
= Troubleshooting =<br />
Answers to some common computer problems<br />
<br />
1. If you forgot the code you need to use the copiers, login to one of the department's linux PCs, open a terminal window and type 'whatsmypin'.<br />
<br />
2. 'Macintosh users'. Sometimes the internet connection on a Mac will <br />
freeze. If this happens, click on the following"<br />
System Preferences -> Network -> DCHP -> Advanced -> renew DHCP lease</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminarindex.html&diff=22951SIAM Student Chapter Seminarindex.html2022-03-09T18:49:24Z<p>Nagreen: Redirected page to SIAM Student Chapter Seminar</p>
<hr />
<div>#REDIRECT [[SIAM_Student_Chapter_Seminar]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminarindex.html&diff=22950SIAM Student Chapter Seminarindex.html2022-03-09T18:49:11Z<p>Nagreen: </p>
<hr />
<div>REDIRECT [[SIAM_Student_Chapter_Seminar]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminarindex.html&diff=22949SIAM Student Chapter Seminarindex.html2022-03-09T18:48:07Z<p>Nagreen: Created page with "This link goes to https://hilbert.math.wisc.edu/wiki/index.php/SIAM_Student_Chapter_Seminar"</p>
<hr />
<div>This link goes to https://hilbert.math.wisc.edu/wiki/index.php/SIAM_Student_Chapter_Seminar</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Math_Computer_Policies&diff=22797Math Computer Policies2022-02-21T18:19:35Z<p>Nagreen: </p>
<hr />
<div>Here are the Official Math Computer Policies<br />
<br />
=== Account Policies ===<br />
<br />
Computer Account Policy<br />
<br />
The following Resolution was proposed and approved by the Mathematics<br />
Department on September 23, 1993 and revised on July, 1998 and August, 2005.<br />
<br />
<br />
1. The computing facilities are for the use of members of the department,<br />
specifically, for Math Department faculty (including emeriti and visitors), <br />
staff, and current graduate students.<br />
<br />
2. Accounts of people no longer members of the department (in the sense of 1.)<br />
will be removed after a suitable grace period to allow them time transfer <br />
their files to their new accounts.<br />
The timetable for removal is given by the following guidelines (3,4,5):<br />
<br />
3. Normally, accounts of people who leave will be deleted on October 1 <br />
following the time of their departure. Former members who need extra time <br />
to relocate may request a temporary 6 month extension of their accounts.<br />
<br />
4. Students who earned their PhDs during the past academic year and Van Vleck<br />
Professors whose appointments have ended may request a 1 year extension of <br />
their accounts. <br />
<br />
5. In special circumstances, someone not a member of the department may<br />
be given temporary access to the departmental computing facilities, for the<br />
purpose of facilitating joint work with a faculty member of the department.<br />
A department member may also request a temporary web site for a math-related<br />
function such as a conference. These web sites should have a clear end date.<br />
The department member involved should contact the IT Manager explaining the <br />
particular need, and will bear full responsibility<br />
for that account. Such accounts and web sites will be reviewed periodically <br />
and terminated with warning when they are no longer active. <br />
<br />
6. In individual cases where the application of 3,4,5 is unclear, the IT Manager will decide when to remove an account.<br />
<br />
=== Web Services and Scripting Policies ===<br />
<br />
<br />
Policy on Web Servers, Web Services<br />
<br />
In order to ensure the security and integrity of<br />
the Van Vleck computer network, all web servers in Van Vleck <br />
will be managed by the Math Department's computer staff. <br />
They will set up and maintain them to make sure that they<br />
meet University security and privacy standards. <br />
<br />
These web servers and the services they offer must serve<br />
legitimate Math Department functions (for example,<br />
instruction, research support and outreach) and<br />
must comply with University policies for appropriate<br />
use and FERPA policies for privacy.<br />
<br />
Forms, if needed, are best accomplished via Google Forms.<br />
[https://sites.google.com/a/wisc.edu/use-cases-for-google-forms/]<br />
<br />
If the web application requires specialized scripts please<br />
confer with the computer staff first.<br />
<br />
=== Laptop Policies ===<br />
<br />
You are welcome to bring your laptop in to the Department in order<br />
to do Mathematical work. However, if you connect it to the network<br />
via either the Wireless network or a cable, you are responsible for<br />
<br />
* Making sure that it is virus and spyware free. University members can pick up a free CD with virus protection software from DoIT or download it [https://it.wisc.edu/services/antivirus-software/ here]<br />
<br />
* The Math Department's computer staff is primarily responsible for installing, maintaining and upgrading the computers in Van Vleck with belong to the Department. They may help you set up your computer initially or troubleshoot hardware and software problems, but '''only if they have extra time'''. [http://www.doit.wisc.edu DoIT] provides computer repair services for a fee.<br />
<br />
=== University Computer Policies ===<br />
<br />
The University of Wisconsin has it's own policies for IT, and we must follow them.<br />
https://policy.wisc.edu<br />
<br />
The Math Department users must also follow these guidelines.<br />
<br />
=== University Computer Policies ===<br />
<br />
The IT staff will occasionally scan for sensitive data on our servers, and may contact users on how to best dispose of sensitive data on their network shares. Sensitive data includes a class of personal identifying information, but in our case is mostly Social Security Numbers. <br />
<br />
It is best to NEVER store a Social Security Number on your electronic media. If one is found on your system, you'll be asked on how you'd prefer to dispose of it; either by deletion or by transferring to an encrypted service such as box.com. Dropbox is not encrypted and not an appropriate storage mechanism for sensitive data. <br />
<br />
If you have questions on what is sensitive data, how we identify sensitive data or anything thing else related to IT security, please ask the IT Staff (staff@math.wisc.edu)</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Math_Accounts&diff=22796Math Accounts2022-02-21T18:15:24Z<p>Nagreen: </p>
<hr />
<div>==Math Department Computer Accounts==<br />
<br />
The Math Department computing facilities are only for the faculty, staff and graduate students of the Math Department. This web site assumes that you are a faculty member or a graduate student of the Math Department.<br />
<br />
You should have been given an authorized Math Department computer account, i.e. a username and password. With an authorized account you're free to use the Math Department's computing facilities described on this site's index page. If you didn't get a username and password, come see the Math Department's computer staff, in room 507 or 515.<br />
<br />
Computer accounts of people no longer members of the Math Department in the above sense will be deleted after a short grace period. During that period, such users can save their user files elsewhere. Here are a few more details on this topic.<br />
<br />
* In exceptional circumstances, someone not a member of the Department may be given temporary access to the departmental computing facilities, for the purpose of facilitating joint work with a faculty member of the Department. The faculty member involved should email the IT Manager (nagreen@math.wisc.edu) explaining the particular need, and will bear full responsibility for that account. Such requests will be reviewed yearly.<br />
* Normally, accounts of people who leave will be deleted on Octber 1 following the time of their departure. Former members who need extra time to relocate may request a temporary (6 month extension) of their accounts.<br />
* Students who earned their PhDs during the past academic year may request a one year extension of their accounts.<br />
* In cases of former Math Department members that don't fit the above guidelines, the IT Manager will decide when to remove an account.<br />
* The Math Department maintains several e-mail lists. Some of them (faculty, graduate, supportstaff) are used primarily to notify people about matters related to their jobs and, hence, users can neither subscribe to nor unsubscribe from these lists. The lists will be reviewed twice a year to make sure that the people on them are members of the Math Department. If someone wants to remain on a list, they may request this from the IT Manager.</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Computer_Help&diff=22795Computer Help2022-02-21T18:13:23Z<p>Nagreen: /* Accounts and Policies */</p>
<hr />
<div>'''Computer Help'''<br />
This is a guide to the computer facilities, services and software available at the Math department of the University of Wisconsin. Most of the facilities are for department's the faculty, graduate students and staff. <br />
<br />
==How to report an issue==<br />
* https://go.wisc.edu/mathit<br />
<br />
== Accounts and Policies ==<br />
* [[Math Accounts]]<br />
* [[Math Computer Policies]]<br />
* [[Quotas]]<br />
* [[University Computer Policies]]<br />
* [[Math Apps]]<br />
<br />
=== Account Set Up ===<br />
Every person in the math department should be provided the opportunity to set up an account. That account is used for ...<br />
<br />
* computer login for math department computers<br />
* the ability to print to department printers<br />
* file storage on the department file server<br />
* access to math department servers for math software<br />
* the ability to login to various department web pages<br />
<br />
This is different from your WiscMail account, which is used for <br />
<br />
* payroll<br />
* access to Canvas<br />
* access to UW system level IT resources such as Google Apps and UWNet wireless<br />
* your UW wiscmail account<br />
* login to various UW protected webpages hosted throughout the university<br />
* WiscVPN<br />
<br />
=== Dealing With Spam ===<br />
<br />
The University runs Office 365, which has some spam controls built in. <br />
<br />
There's two parts to the UW's spam control.<br />
<br />
* the Clutter Folder [https://kb.wisc.edu/page.php?id=53321]<br />
* the Junk Mail folder [https://kb.wisc.edu/page.php?id=45051]<br />
<br />
Questions regarding these two methods should be directed to the DoIT Help Desk. (264-HELP, 4357)<br />
<br />
=== Vacation Mail ===<br />
<br />
[https://kb.wisc.edu/page.php?id=32606] How to set up an auto-reply. <br />
<br />
=== Forwarding your e-mail ===<br />
<br />
[https://kb.wisc.edu/page.php?id=36539]<br />
<br />
=== Leaving the Department ===<br />
If you leave the Math Department, we will occasionally remove old accounts. In some cases, we can leave an account in place for <br />
<br />
#) users that are continuing to collaborate with faculty or staff for research<br />
#) users that wish to continue to receive mail under their math account for a time. <br />
<br />
While we can't guarantee infinite continuation of your email account because that is controlled by DoIT, we do have some methods at our command to make this more streamlined and less prone to being deactivated.<br />
<br />
Generally, we remove accounts in October and March. In most cases, you'll be told in an email that we intend on doing this.<br />
<br />
If you feel you fall under either of the two case scenarios listed above, please email nagreen@math.wisc.edu.<br />
<br />
=== E-mail Web Forms ===<br />
<br />
You can create a web page in your server space.<br />
Here's how: [https://sites.google.com/a/wisc.edu/math-intranet/home/computing/html]<br />
<br />
== '''Facilities''' ==<br />
<br />
The facilities and equipment described below are for use by UW Math department faculty and graduate students on the UW Madison Campus and, preferably, in Van Vleck hall.<br />
<br />
* '''Mobile Computers and Projectors''' <br><br />
Instructors may borrow laptop computers and projectors for demonstrations in any Van Vleck classroom. This equipment is kept in the AMP Library in Chamberlin Hall. You may check them out for up to 4 hours using your UW ID card. The math library also has an assortment of VGA and HDMI video cables which can be used to connect a PC, Macintosh computer or iPad to a projector. One of the projectors has built in speakers and a DVD player. It also has two microphones which can be connected to it. WARNING: the laptops available for check out are somewhat old and have only basic software (MS Office, TeX) on them. It is far better to use your own computer with the Department's projectors.<br />
<br />
* '''Ceiling Mounted Projectors''' <br><br />
<br />
Classrooms B102, B107, B130, B215, B231 and B223, B239, the 901 seminar room, and the 911 Lounge each have a ceiling mounted projector. These projectors provide better displays than the mobile units. They can be used with a laptop computer. If you want to reserve one of these rooms, contact Sharon Paulson at paulson@math.wisc.edu. Keep in mind, though, that they're heavily booked and usually only available at the beginning or end of the day.<br />
<br />
The Math Department's computer staff maintain the projectors in 901 and 911. All the others are maintained by the UW Physical Plant. Please contact Derek Dombrowski about them. You will need an access code to use them and a key if you want to use the document camera or microphone with them.<br />
Here is Derek's contact information:<br />
Derek Dombrowski<br />
373A BASCOM HALL<br />
ddombrowski@fpm.wisc.edu<br />
(608) 265-9697<br />
(608) 516-5993<br />
<br />
* [[Scanners]]<br />
<br />
= Printing =<br />
<br />
Math Dept Printers<br />
{|<br />
! Location<br />
! PrinterName<br />
! Printer Type<br />
|-<br />
|3rd hall<br />
|3<br />
|Ricoh IMC6000<br />
|-<br />
|4th hall<br />
|4<br />
|Ricoh IMC6000<br />
|-<br />
|5th hall<br />
|5<br />
|Ricoh IMC6000<br />
|-<br />
|6th hall<br />
|6<br />
|Ricoh IMC6000<br />
|-<br />
|7th hall<br />
|7<br />
|Ricoh IMC6000<br />
|-<br />
|8th hall<br />
|8<br />
|Ricoh IMC6000<br />
|-<br />
|101B VV<br />
|a<br />
|HP LaserJet 600 M601<br />
|}<br />
<br />
During the summer of 2020, new Ricoh IMC 6000 printers were placed on floors 3-8. We will also switched from LPRNG to CUPS (the Common Unix Printing System) on our unix print servers. <br />
<br />
As of 2014, we stopped charging for overages in printing, but want people to consider carefully the costs of consumables and paper, and the impact on the climate from overuse of paper. Please limit your use of our copiers to fewer than 250 pages a month.<br />
<br />
== Supplies ==<br />
If the printers run out of paper, please get more paper from the Copy Center on the second floor<br />
and place it in the printers. If you are unsure how to do this, ask the computer staff for assistance. For assistance with other problems (no toner, paper jams, etc. ) see Henry Mayes in 507 (for issues with the Ricoh copiers) and Sharon Paulson in 220 (for help with the printers in B127 and 101b). <br />
<br />
See the [http://www.cups.org/ cups guide] for more detailed information on printing with cups.<br />
Click on the links below to learn how to use each function with the Ricoh copiers.<br />
<br />
== [[Ricoh Copier FAQ]] ==<br />
<br />
Only people with computer accounts in the UW Math Department will be allowed to use the Van Vleck Ricoh copiers. If you have a math account, you will receive a code to use for copying. These <br />
codes will be mailed out once a year in September after old accounts are deleted and new ones added. '''NOTE''': if you forget your copier code, login to one of<br />
the math department linux PCs and type '''whatsmypin'''.<br />
<br />
1. You copier code is only required for copying. Although the<br />
default display shows the copier login, you do not have to login<br />
in order to print or scan. Just push the buttons at the left<br />
to select the scanner or printer function.<br />
<br />
2. Your code can be used on any of the copiers on floors 3-8.<br />
Do not use the copiers on the second floor. They are reserved<br />
for the administrative staff.<br />
<br />
3. After you have finished copying, do not touch the display.<br />
Your login will time out after 60 seconds.<br />
<br />
4. Everyone with a math dept account is urged to keep their printing <br />
at fewer than 250 pages a month. The Math Department does keep a count of <br />
printing totals. You may receive a report each month on your total printing. <br />
At the end of the month, these are zeroed out.<br />
<br />
5. How to create a multi-page PDF document: Most people will want<br />
to create a multipage PDF scan of their document (instead of the <br />
default which is a single page TIFF document). To do this press the<br />
SCANNER button to the left of the display. Select SEND FILE TYPE/NAME<br />
in the left hand column of the display, then select MULTI-PAGE -> PDF<br />
<br />
== [[Ricoh Printing FAQ]] ==<br />
<br />
* [[Using the Ricoh with Linux]] (command line printing)<br />
* [[Using a Ricoh Printer on a Macintosh]]<br />
* [[Using a Ricoh Printer on a PC]]<br />
* [[Troubleshooting]]<br />
<br />
== [[Ricoh Scanner FAQ]] ==<br />
<br />
= Remote Access =<br />
<br />
[https://www.math.wisc.edu/wiki/index.php/Accessing_your_Math_department_network_space | Using ssh, sftp, and Sshfs]<br />
<br />
= TeX/LaTeX =<br />
TeX and LaTeX are supported on the Math Department computers. To learn more about<br />
Typesetting with LaTeX we recommend the following [http://www.latex-project.org/guides/books.html site]. Mediawiki has some support for LaTeX<br />
as the following example shows:<br />
<br />
<math><br />
\int_{[0, 1]^n} <br />
\left| \sum_{k = 1}^n \mathrm{e}^{2 \pi \mathrm{i} \, x_k} \right|^s \mathrm{d}\boldsymbol{x}<br />
</math><br />
<br />
= Unix =<br />
<br />
==Manipulating PDF files ==<br />
<br />
The ''pdftk'' toolkit provides several useful tools for manipulating PDF files without using<br />
Adobe Acrobat Pro. Here are some examples:<br />
<br />
1. This command will split off the first 15 pages of the file NSFProposal.pdf and save it to 'front.pdf'. Substituting 'cat 16-end' for 'cat 1-15' will save the second half of the file.<br />
<br />
pdftk NSFProposal.pdf cat 1-15 output front.pdf<br />
<br />
2. This command will merge two (or more) pdf files:<br />
<br />
pdftk 1.pdf 2.pdf 3.pdf cat output 123.pdf<br />
<br />
You can find more examples at [http://www.pdflabs.com/docs/pdftk-cli-examples/ pdftk-examples]<br />
= Troubleshooting =<br />
Answers to some common computer problems<br />
<br />
1. If you forgot the code you need to use the copiers, login to one of the department's linux PCs, open a terminal window and type 'whatsmypin'.<br />
<br />
2. 'Macintosh users'. Sometimes the internet connection on a Mac will <br />
freeze. If this happens, click on the following"<br />
System Preferences -> Network -> DCHP -> Advanced -> renew DHCP lease<br />
<br />
3. [[Moving back to Debian from Ubuntu]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Computer_Help&diff=22793Computer Help2022-02-21T15:07:30Z<p>Nagreen: /* COVID Computing */</p>
<hr />
<div>'''Computer Help'''<br />
This is a guide to the computer facilities, services and software available at the Math department of the University of Wisconsin. Most of the facilities are for department's the faculty, graduate students and staff. <br />
<br />
==How to report an issue==<br />
* https://go.wisc.edu/mathit<br />
<br />
== Accounts and Policies ==<br />
* [[Math Accounts]]<br />
* [[Math Computer Policies]]<br />
* [[Quotas]]<br />
* [[University Computer Policies]]<br />
* [[Math Apps]]<br />
<br />
=== Account Set Up ===<br />
Every person in the math department should be provided the opportunity to set up an account. That account is used for ...<br />
<br />
* computer login for math department computers<br />
* the ability to print to department printers<br />
* file storage on the department file server<br />
* access to math department servers for math software<br />
* the ability to login to various department web pages<br />
<br />
This is different from your WiscMail account, which is used for <br />
<br />
* payroll<br />
* access to Canvas<br />
* access to UW system level IT resources such as Google Apps and UWNet wireless<br />
* your UW wiscmail account<br />
* login to various UW protected webpages hosted throughout the university<br />
* WiscVPN<br />
<br />
To set up your IMAP email client<br />
<br />
go to [https://kb.wisc.edu/page.php?id=28350]<br />
<br />
If you have problems with this, please let us know: staff@math.wisc.edu<br />
<br />
=== Dealing With Spam ===<br />
<br />
The University runs Office 365, which has some spam controls built in. <br />
<br />
There's two parts to the UW's spam control.<br />
<br />
* the Clutter Folder [https://kb.wisc.edu/page.php?id=53321]<br />
* the Junk Mail folder [https://kb.wisc.edu/page.php?id=45051]<br />
<br />
Questions regarding these two methods should be directed to the DoIT Help Desk. (264-HELP, 4357)<br />
<br />
=== Vacation Mail ===<br />
<br />
[https://kb.wisc.edu/page.php?id=32606]Head over to the UW KB.<br />
<br />
=== Forwarding your e-mail ===<br />
<br />
[https://kb.wisc.edu/page.php?id=36539]<br />
<br />
=== Leaving the Department ===<br />
If you leave the Math Department, we will occasionally remove old accounts. In some cases, we can leave an account in place for <br />
<br />
#) users that are continuing to collaborate with faculty or staff for research<br />
#) users that wish to continue to receive mail under their math account for a time. <br />
<br />
While we can't guarantee infinite continuation of your email account because that is controlled by DoIT, we do have some methods at our command to make this more streamlined and less prone to being deactivated.<br />
<br />
Generally, we remove accounts in October and March. In most cases, you'll be told in an email that we intend on doing this.<br />
<br />
If you feel you fall under either of the two case scenarios listed above, please email nagreen@math.wisc.edu.<br />
<br />
=== E-mail Web Forms ===<br />
<br />
You can create a web page in your server space.<br />
Here's how: [https://sites.google.com/a/wisc.edu/math-intranet/home/computing/html]<br />
<br />
== '''Facilities''' ==<br />
<br />
The facilities and equipment described below are for use by UW Math department faculty and graduate students on the UW Madison Campus and, preferably, in Van Vleck hall.<br />
<br />
* '''Mobile Computers and Projectors''' <br><br />
Instructors may borrow laptop computers and projectors for demonstrations in any Van Vleck classroom. This equipment is kept in the AMP Library in Chamberlin Hall. You may check them out for up to 4 hours using your UW ID card. The math library also has an assortment of VGA and HDMI video cables which can be used to connect a PC, Macintosh computer or iPad to a projector. One of the projectors has built in speakers and a DVD player. It also has two microphones which can be connected to it. WARNING: the laptops available for check out are somewhat old and have only basic software (MS Office, TeX) on them. It is far better to use your own computer with the Department's projectors.<br />
<br />
* '''Ceiling Mounted Projectors''' <br><br />
<br />
Classrooms B102, B107, B130, B215, B231 and B223, B239, the 901 seminar room, and the 911 Lounge each have a ceiling mounted projector. These projectors provide better displays than the mobile units. They can be used with a laptop computer. If you want to reserve one of these rooms, contact Sharon Paulson at paulson@math.wisc.edu. Keep in mind, though, that they're heavily booked and usually only available at the beginning or end of the day.<br />
<br />
The Math Department's computer staff maintain the projectors in 901 and 911. All the others are maintained by the UW Physical Plant. Please contact Derek Dombrowski about them. You will need an access code to use them and a key if you want to use the document camera or microphone with them.<br />
Here is Derek's contact information:<br />
Derek Dombrowski<br />
373A BASCOM HALL<br />
ddombrowski@fpm.wisc.edu<br />
(608) 265-9697<br />
(608) 516-5993<br />
<br />
* [[Scanners]]<br />
<br />
= Printing =<br />
<br />
Math Dept Printers<br />
{|<br />
! Location<br />
! PrinterName<br />
! Printer Type<br />
|-<br />
|3rd hall<br />
|3<br />
|Ricoh IMC6000<br />
|-<br />
|4th hall<br />
|4<br />
|Ricoh IMC6000<br />
|-<br />
|5th hall<br />
|5<br />
|Ricoh IMC6000<br />
|-<br />
|6th hall<br />
|6<br />
|Ricoh IMC6000<br />
|-<br />
|7th hall<br />
|7<br />
|Ricoh IMC6000<br />
|-<br />
|8th hall<br />
|8<br />
|Ricoh IMC6000<br />
|-<br />
|101B VV<br />
|a<br />
|HP LaserJet 600 M601<br />
|}<br />
<br />
During the summer of 2020, new Ricoh IMC 6000 printers were placed on floors 3-8. We will also switched from LPRNG to CUPS (the Common Unix Printing System) on our unix print servers. <br />
<br />
As of 2014, we stopped charging for overages in printing, but want people to consider carefully the costs of consumables and paper, and the impact on the climate from overuse of paper. Please limit your use of our copiers to fewer than 250 pages a month.<br />
<br />
== Supplies ==<br />
If the printers run out of paper, please get more paper from the Copy Center on the second floor<br />
and place it in the printers. If you are unsure how to do this, ask the computer staff for assistance. For assistance with other problems (no toner, paper jams, etc. ) see Henry Mayes in 507 (for issues with the Ricoh copiers) and Sharon Paulson in 220 (for help with the printers in B127 and 101b). <br />
<br />
See the [http://www.cups.org/ cups guide] for more detailed information on printing with cups.<br />
Click on the links below to learn how to use each function with the Ricoh copiers.<br />
<br />
== [[Ricoh Copier FAQ]] ==<br />
<br />
Only people with computer accounts in the UW Math Department will be allowed to use the Van Vleck Ricoh copiers. If you have a math account, you will receive a code to use for copying. These <br />
codes will be mailed out once a year in September after old accounts are deleted and new ones added. '''NOTE''': if you forget your copier code, login to one of<br />
the math department linux PCs and type '''whatsmypin'''.<br />
<br />
1. You copier code is only required for copying. Although the<br />
default display shows the copier login, you do not have to login<br />
in order to print or scan. Just push the buttons at the left<br />
to select the scanner or printer function.<br />
<br />
2. Your code can be used on any of the copiers on floors 3-8.<br />
Do not use the copiers on the second floor. They are reserved<br />
for the administrative staff.<br />
<br />
3. After you have finished copying, do not touch the display.<br />
Your login will time out after 60 seconds.<br />
<br />
4. Everyone with a math dept account is urged to keep their printing <br />
at fewer than 250 pages a month. The Math Department does keep a count of <br />
printing totals. You may receive a report each month on your total printing. <br />
At the end of the month, these are zeroed out.<br />
<br />
5. How to create a multi-page PDF document: Most people will want<br />
to create a multipage PDF scan of their document (instead of the <br />
default which is a single page TIFF document). To do this press the<br />
SCANNER button to the left of the display. Select SEND FILE TYPE/NAME<br />
in the left hand column of the display, then select MULTI-PAGE -> PDF<br />
<br />
== [[Ricoh Printing FAQ]] ==<br />
<br />
* [[Using the Ricoh with Linux]] (command line printing)<br />
* [[Using a Ricoh Printer on a Macintosh]]<br />
* [[Using a Ricoh Printer on a PC]]<br />
* [[Troubleshooting]]<br />
<br />
== [[Ricoh Scanner FAQ]] ==<br />
<br />
= Remote Access =<br />
<br />
[https://www.math.wisc.edu/wiki/index.php/Accessing_your_Math_department_network_space | Using ssh, sftp, and Sshfs]<br />
<br />
= TeX/LaTeX =<br />
TeX and LaTeX are supported on the Math Department computers. To learn more about<br />
Typesetting with LaTeX we recommend the following [http://www.latex-project.org/guides/books.html site]. Mediawiki has some support for LaTeX<br />
as the following example shows:<br />
<br />
<math><br />
\int_{[0, 1]^n} <br />
\left| \sum_{k = 1}^n \mathrm{e}^{2 \pi \mathrm{i} \, x_k} \right|^s \mathrm{d}\boldsymbol{x}<br />
</math><br />
<br />
= Unix =<br />
<br />
==Manipulating PDF files ==<br />
<br />
The ''pdftk'' toolkit provides several useful tools for manipulating PDF files without using<br />
Adobe Acrobat Pro. Here are some examples:<br />
<br />
1. This command will split off the first 15 pages of the file NSFProposal.pdf and save it to 'front.pdf'. Substituting 'cat 16-end' for 'cat 1-15' will save the second half of the file.<br />
<br />
pdftk NSFProposal.pdf cat 1-15 output front.pdf<br />
<br />
2. This command will merge two (or more) pdf files:<br />
<br />
pdftk 1.pdf 2.pdf 3.pdf cat output 123.pdf<br />
<br />
You can find more examples at [http://www.pdflabs.com/docs/pdftk-cli-examples/ pdftk-examples]<br />
= Troubleshooting =<br />
Answers to some common computer problems<br />
<br />
1. If you forgot the code you need to use the copiers, login to one of the department's linux PCs, open a terminal window and type 'whatsmypin'.<br />
<br />
2. 'Macintosh users'. Sometimes the internet connection on a Mac will <br />
freeze. If this happens, click on the following"<br />
System Preferences -> Network -> DCHP -> Advanced -> renew DHCP lease<br />
<br />
3. [[Moving back to Debian from Ubuntu]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=22651SIAM Student Chapter Seminar2022-02-03T18:33:02Z<p>Nagreen: </p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 4 PM<br />
*'''Where:''' See list of talks below <br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
==Spring 2022==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Feb 7, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person | Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
|-<br />
| Feb 14, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person | Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
|-<br />
| Feb 21, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person | Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
<br />
|}<br />
<br />
<br />
== Abstracts ==<br />
<br />
=== Feb 7 ===<br />
<br />
<br />
=== Feb 14 ===<br />
<br />
=== Feb 21 ===<br />
<br />
<br />
== Past Semesters ==<br />
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar/Fall2021&diff=22650SIAM Student Chapter Seminar/Fall20212022-02-03T18:31:30Z<p>Nagreen: /* Fall 2021 */</p>
<hr />
<div>== Fall 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Sept 20, 4 PM<br />
| Ingraham 214<br />
| [https://sites.google.com/view/julialindberg/home/ Julia Lindberg] (Electrical and Computer Engineering)<br />
|''[[#Sept 20, Julia Lindberg |Polynomial system solving in applications]]''<br />
|-<br />
|-<br />
| Sept 27, 4 PM, <br />
| Zoom (refreshments and conference call in 307)<br />
| Wil Cocke (Developer for [https://www.arcyber.army.mil/ ARCYBER])<br />
| ''[[#Sept 27, Wil Cocke |Job talk-Software Development/Data Science]]''<br />
|<br />
|-<br />
|-<br />
| Oct 4, '''2:45 PM'''<br />
| B119 Van Vleck<br />
| [https://sites.google.com/wisc.edu/nair-anjali/home/ Anjali Nair] (Math)<br />
| ''[[#Oct 4, Anjali Nair|Reconstruction of Reflection Coefficients Using the Phonon Transport Equation]]''<br />
|<br />
|-<br />
|-<br />
| Oct 18, 4 PM<br />
| 6104 Social Sciences<br />
| [https://jasonltorchinsky.github.io/ Jason Tochinsky] (Math)<br />
| ''[[#Oct 18, Jason Torchinsky|Improving the Vertical Remapping Algorithm in the Department of Energy’s Energy Exascale Earth Systems Model]]''<br />
|<br />
|-<br />
|-<br />
| Oct 25, 4 PM,<br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/patricktbardsley/ Patrick Bardsley] (Senior Machine Learning Engineer at [https://www.cirrus.com/ Cirrus Logic])<br />
| ''[[#Oct 25, Patrick Bardsley|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 8, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/libanmohamed496/ Liban Mohamed] (Machine Learning Engineer at [https://www.mitre.org/ MITRE])<br />
| ''[[#Nov 8, Liban Mohamed|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 15, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/kurt-ehlert-320b8397/ Kurt Ehlert] (Trading Strategy Developer at [https://auros.global/about/ Auros])<br />
| ''[[#Nov 15, Kurt Ehlert|Job Talk-Cryptocurrency Trading]]''<br />
|<br />
|-<br />
|-<br />
| Nov 29, 4 PM<br />
| 9th floor lounge<br />
| [https://people.math.wisc.edu/~boakley/ Bryan Oakley] (Math)<br />
| ''[[#Nov 29, Bryan Oakley|Optimal Spatially Dependent Diffusion]]''<br />
|<br />
|-<br />
|-<br />
| Dec 6, 4 PM<br />
| 9th floor lounge<br />
| [https://sites.google.com/view/hongxuchen/ Hongxu Chen] (Math)<br />
| ''[[#Dec 6, Hongxu Chen|Boltzmann equation with Cercignani-Lampis boundary]]''<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== Sept 20, Julia Lindberg===<br />
Polynomial systems arise naturally in many applications in engineering and the sciences. This talk will outline classes of homotopy continuation algorithms used to solve them. I will then describe ways in which structures such as irreducibility, symmetry and sparsity can be used to improve computational speed. The efficacy of these algorithms will be demonstrated on systems in power systems engineering, statistics and optimization<br />
<br />
<br />
=== Sept 27, Wil Cocke ===<br />
I mostly work as a software developer with an emphasis on data science projects dealing with various Command specific projects. The data science life-cycle is fairly consistent across industries: collect, clean, explore, model, interpret, and repeat with a goal of providing insight to the organization. During my talk, I will share some lessons learned for mathematicians interested in transitioning to software development/ data science. <br />
<br />
<br />
=== Oct 4, Anjali Nair ===<br />
The phonon transport equation is used to model heat conduction in solid materials. I will talk about how we use it to solve an inverse problem to reconstruct the thermal reflection coefficient at an interface. This takes the framework of a PDE constrained optimization problem, and I will also mention the stochastic methods used to solve it.<br />
<br />
<br />
=== Oct 18, Jason Torchinsky ===<br />
A vertical Lagrangian coordinate has been used in global climate models for nearly two decades and has several advantages over other discretizations, including reducing the dimensionality of the physical problem. As the Lagrangian surfaces deform over time, it is necessary to accurately and conservatively remap the vertical Lagrangian coordinate back to a fixed Eulerian coordinate. A popular choice of remapping algorithm is the piecewise parabolic method, a modified version of which is used in the atmospheric component of the Department of Energy's Energy Exascale Earth System Model. However, this version of the remapping algorithm creates unwanted noise at the model top and planetary surface for several standard test cases. We explore four alternative modifications to the algorithm and show that the most accurate of these eliminates this noise. <br />
<br />
<br />
=== Oct 25, Patrick Bardsley ===<br />
During the course of a PhD, students typically enter a proverbial `coal mine’ to extract new information about one or more problems, and in the process become a domain expert in a small niche of the technical and scientific world. Upon leaving the academy, unless one lands a job in their niche domain, much of their problem- and domain-specific knowledge is no longer essential. However, mathematics is broad and general, arguably the most general of all scientific disciplines. This fact alone is a mathematician’s greatest asset and ‘leg-up’ when entering the industrial workforce. In this talk, I will discuss some details of my work, both inside and outside of the academy, with the goal of highlighting the skills and concepts that have been the most general and transferable for me. For example, my academic work on hyperbolic inverse problems helped me learn signal processing concepts I now use daily, while my studies on polycrystalline grain growth pushed me to learn thermodynamics, which translated well to the information theory concepts I now utilize. I will also give you some idea of my current day-to-day responsibilities, and close with my thoughts and suggestions on job searches.<br />
<br />
<br />
=== Nov 8, Liban Mohamed ===<br />
I work as a researcher at MITRE, a company that manages R&D contracts (FFRDCs) with federal agencies. I am nominally a machine learning engineer, but my department supports a diverse array of initiatives with the IRS. In this talk I'll give an overview of the FFRDC space, give a sketch of what I work on and how I spend my time, and share my thoughts about navigating the transition from academia to industry.<br />
<br />
<br />
=== Nov 15, Kurt Ehlert ===<br />
After graduating from the UW, I ventured into the world of trading. My first job was at Virtu, a high-frequency market-maker, and currently I work at Auros, which is a high-frequency trading firm that focuses on cryptocurrencies. During the talk, I will give an overview of the industry, job market, and interview process from the perspective of a "quant". Then I will describe the day-to-day work and give a high-level description of typical projects. <br />
<br />
<br />
=== Nov 29, Bryan Oakley ===<br />
The solution to the diffusion equation is known to converge exponentially to its steady state, and the rate is given by the spectral gap of the elliptic operator. Using variational techniques, we will maximize the spectral gap over choices of spatially dependent diffusion functions. Using this characterization, we can obtain bounds on the optimal rate of convergence.<br />
<br />
=== Dec 6, Hongxu Chen ===<br />
Boltzmann equation is a fundamental kinetic equation that describes the dynamics of dilute gas. In this talk I will focus on the boundary value problem of the Boltzmann equation and introduce the Cercignani-Lampis boundary, which is a physical boundary that describes the intermediate reflection law between diffuse reflection and specular reflection. <br />
<br />
<br />
<br />
<br></div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar/Fall2021&diff=22649SIAM Student Chapter Seminar/Fall20212022-02-03T18:30:57Z<p>Nagreen: Created page with "== Fall 2021 == {| cellpadding="8" !align="left" | date and time !align="left" | location !align="left" | speaker !align="left" | title |- | Sept 20, 4 PM | Ingraham 214 | [..."</p>
<hr />
<div>== Fall 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Sept 20, 4 PM<br />
| Ingraham 214<br />
| [https://sites.google.com/view/julialindberg/home/ Julia Lindberg] (Electrical and Computer Engineering)<br />
|''[[#Sept 20, Julia Lindberg |Polynomial system solving in applications]]''<br />
|-<br />
|-<br />
| Sept 27, 4 PM, <br />
| Zoom (refreshments and conference call in 307)<br />
| Wil Cocke (Developer for [https://www.arcyber.army.mil/ ARCYBER])<br />
| ''[[#Sept 27, Wil Cocke |Job talk-Software Development/Data Science]]''<br />
|<br />
|-<br />
|-<br />
| Oct 4, '''2:45 PM'''<br />
| B119 Van Vleck<br />
| [https://sites.google.com/wisc.edu/nair-anjali/home/ Anjali Nair] (Math)<br />
| ''[[#Oct 4, Anjali Nair|Reconstruction of Reflection Coefficients Using the Phonon Transport Equation]]''<br />
|<br />
|-<br />
|-<br />
| Oct 18, 4 PM<br />
| 6104 Social Sciences<br />
| [https://jasonltorchinsky.github.io/ Jason Tochinsky] (Math)<br />
| ''[[#Oct 18, Jason Torchinsky|Improving the Vertical Remapping Algorithm in the Department of Energy’s Energy Exascale Earth Systems Model]]''<br />
|<br />
|-<br />
|-<br />
| Oct 25, 4 PM,<br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/patricktbardsley/ Patrick Bardsley] (Senior Machine Learning Engineer at [https://www.cirrus.com/ Cirrus Logic])<br />
| ''[[#Oct 25, Patrick Bardsley|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 8, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/libanmohamed496/ Liban Mohamed] (Machine Learning Engineer at [https://www.mitre.org/ MITRE])<br />
| ''[[#Nov 8, Liban Mohamed|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 15, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/kurt-ehlert-320b8397/ Kurt Ehlert] (Trading Strategy Developer at [https://auros.global/about/ Auros])<br />
| ''[[#Nov 15, Kurt Ehlert|Job Talk-Cryptocurrency Trading]]''<br />
|<br />
|-<br />
|-<br />
| Nov 29, 4 PM<br />
| 9th floor lounge<br />
| [https://people.math.wisc.edu/~boakley/ Bryan Oakley] (Math)<br />
| ''[[#Nov 29, Bryan Oakley|Optimal Spatially Dependent Diffusion]]''<br />
|<br />
|-<br />
|-<br />
| Dec 6, 4 PM<br />
| 9th floor lounge<br />
| [https://sites.google.com/view/hongxuchen/ Hongxu Chen] (Math)<br />
| ''[[#Dec 6, Hongxu Chen|Boltzmann equation with Cercignani-Lampis boundary]]''<br />
|}</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=22648SIAM Student Chapter Seminar2022-02-03T18:30:36Z<p>Nagreen: /* Past Semesters */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 4 PM<br />
*'''Where:''' See list of talks below <br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
==Spring 2022==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Feb 7, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person | Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
|-<br />
| Feb 14, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person | Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
|-<br />
| Feb 21, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person | Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
<br />
|}<br />
<br />
== Fall 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Sept 20, 4 PM<br />
| Ingraham 214<br />
| [https://sites.google.com/view/julialindberg/home/ Julia Lindberg] (Electrical and Computer Engineering)<br />
|''[[#Sept 20, Julia Lindberg |Polynomial system solving in applications]]''<br />
|-<br />
|-<br />
| Sept 27, 4 PM, <br />
| Zoom (refreshments and conference call in 307)<br />
| Wil Cocke (Developer for [https://www.arcyber.army.mil/ ARCYBER])<br />
| ''[[#Sept 27, Wil Cocke |Job talk-Software Development/Data Science]]''<br />
|<br />
|-<br />
|-<br />
| Oct 4, '''2:45 PM'''<br />
| B119 Van Vleck<br />
| [https://sites.google.com/wisc.edu/nair-anjali/home/ Anjali Nair] (Math)<br />
| ''[[#Oct 4, Anjali Nair|Reconstruction of Reflection Coefficients Using the Phonon Transport Equation]]''<br />
|<br />
|-<br />
|-<br />
| Oct 18, 4 PM<br />
| 6104 Social Sciences<br />
| [https://jasonltorchinsky.github.io/ Jason Tochinsky] (Math)<br />
| ''[[#Oct 18, Jason Torchinsky|Improving the Vertical Remapping Algorithm in the Department of Energy’s Energy Exascale Earth Systems Model]]''<br />
|<br />
|-<br />
|-<br />
| Oct 25, 4 PM,<br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/patricktbardsley/ Patrick Bardsley] (Senior Machine Learning Engineer at [https://www.cirrus.com/ Cirrus Logic])<br />
| ''[[#Oct 25, Patrick Bardsley|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 8, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/libanmohamed496/ Liban Mohamed] (Machine Learning Engineer at [https://www.mitre.org/ MITRE])<br />
| ''[[#Nov 8, Liban Mohamed|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 15, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/kurt-ehlert-320b8397/ Kurt Ehlert] (Trading Strategy Developer at [https://auros.global/about/ Auros])<br />
| ''[[#Nov 15, Kurt Ehlert|Job Talk-Cryptocurrency Trading]]''<br />
|<br />
|-<br />
|-<br />
| Nov 29, 4 PM<br />
| 9th floor lounge<br />
| [https://people.math.wisc.edu/~boakley/ Bryan Oakley] (Math)<br />
| ''[[#Nov 29, Bryan Oakley|Optimal Spatially Dependent Diffusion]]''<br />
|<br />
|-<br />
|-<br />
| Dec 6, 4 PM<br />
| 9th floor lounge<br />
| [https://sites.google.com/view/hongxuchen/ Hongxu Chen] (Math)<br />
| ''[[#Dec 6, Hongxu Chen|Boltzmann equation with Cercignani-Lampis boundary]]''<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== Sept 20, Julia Lindberg===<br />
Polynomial systems arise naturally in many applications in engineering and the sciences. This talk will outline classes of homotopy continuation algorithms used to solve them. I will then describe ways in which structures such as irreducibility, symmetry and sparsity can be used to improve computational speed. The efficacy of these algorithms will be demonstrated on systems in power systems engineering, statistics and optimization<br />
<br />
<br />
=== Sept 27, Wil Cocke ===<br />
I mostly work as a software developer with an emphasis on data science projects dealing with various Command specific projects. The data science life-cycle is fairly consistent across industries: collect, clean, explore, model, interpret, and repeat with a goal of providing insight to the organization. During my talk, I will share some lessons learned for mathematicians interested in transitioning to software development/ data science. <br />
<br />
<br />
=== Oct 4, Anjali Nair ===<br />
The phonon transport equation is used to model heat conduction in solid materials. I will talk about how we use it to solve an inverse problem to reconstruct the thermal reflection coefficient at an interface. This takes the framework of a PDE constrained optimization problem, and I will also mention the stochastic methods used to solve it.<br />
<br />
<br />
=== Oct 18, Jason Torchinsky ===<br />
A vertical Lagrangian coordinate has been used in global climate models for nearly two decades and has several advantages over other discretizations, including reducing the dimensionality of the physical problem. As the Lagrangian surfaces deform over time, it is necessary to accurately and conservatively remap the vertical Lagrangian coordinate back to a fixed Eulerian coordinate. A popular choice of remapping algorithm is the piecewise parabolic method, a modified version of which is used in the atmospheric component of the Department of Energy's Energy Exascale Earth System Model. However, this version of the remapping algorithm creates unwanted noise at the model top and planetary surface for several standard test cases. We explore four alternative modifications to the algorithm and show that the most accurate of these eliminates this noise. <br />
<br />
<br />
=== Oct 25, Patrick Bardsley ===<br />
During the course of a PhD, students typically enter a proverbial `coal mine’ to extract new information about one or more problems, and in the process become a domain expert in a small niche of the technical and scientific world. Upon leaving the academy, unless one lands a job in their niche domain, much of their problem- and domain-specific knowledge is no longer essential. However, mathematics is broad and general, arguably the most general of all scientific disciplines. This fact alone is a mathematician’s greatest asset and ‘leg-up’ when entering the industrial workforce. In this talk, I will discuss some details of my work, both inside and outside of the academy, with the goal of highlighting the skills and concepts that have been the most general and transferable for me. For example, my academic work on hyperbolic inverse problems helped me learn signal processing concepts I now use daily, while my studies on polycrystalline grain growth pushed me to learn thermodynamics, which translated well to the information theory concepts I now utilize. I will also give you some idea of my current day-to-day responsibilities, and close with my thoughts and suggestions on job searches.<br />
<br />
<br />
=== Nov 8, Liban Mohamed ===<br />
I work as a researcher at MITRE, a company that manages R&D contracts (FFRDCs) with federal agencies. I am nominally a machine learning engineer, but my department supports a diverse array of initiatives with the IRS. In this talk I'll give an overview of the FFRDC space, give a sketch of what I work on and how I spend my time, and share my thoughts about navigating the transition from academia to industry.<br />
<br />
<br />
=== Nov 15, Kurt Ehlert ===<br />
After graduating from the UW, I ventured into the world of trading. My first job was at Virtu, a high-frequency market-maker, and currently I work at Auros, which is a high-frequency trading firm that focuses on cryptocurrencies. During the talk, I will give an overview of the industry, job market, and interview process from the perspective of a "quant". Then I will describe the day-to-day work and give a high-level description of typical projects. <br />
<br />
<br />
=== Nov 29, Bryan Oakley ===<br />
The solution to the diffusion equation is known to converge exponentially to its steady state, and the rate is given by the spectral gap of the elliptic operator. Using variational techniques, we will maximize the spectral gap over choices of spatially dependent diffusion functions. Using this characterization, we can obtain bounds on the optimal rate of convergence.<br />
<br />
=== Dec 6, Hongxu Chen ===<br />
Boltzmann equation is a fundamental kinetic equation that describes the dynamics of dilute gas. In this talk I will focus on the boundary value problem of the Boltzmann equation and introduce the Cercignani-Lampis boundary, which is a physical boundary that describes the intermediate reflection law between diffuse reflection and specular reflection. <br />
<br />
<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=22647SIAM Student Chapter Seminar2022-02-03T18:29:44Z<p>Nagreen: /* Spring 2022 */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 4 PM<br />
*'''Where:''' See list of talks below <br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
==Spring 2022==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Feb 7, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person | Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
|-<br />
| Feb 14, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person | Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
|-<br />
| Feb 21, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person | Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
<br />
|}<br />
<br />
== Fall 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Sept 20, 4 PM<br />
| Ingraham 214<br />
| [https://sites.google.com/view/julialindberg/home/ Julia Lindberg] (Electrical and Computer Engineering)<br />
|''[[#Sept 20, Julia Lindberg |Polynomial system solving in applications]]''<br />
|-<br />
|-<br />
| Sept 27, 4 PM, <br />
| Zoom (refreshments and conference call in 307)<br />
| Wil Cocke (Developer for [https://www.arcyber.army.mil/ ARCYBER])<br />
| ''[[#Sept 27, Wil Cocke |Job talk-Software Development/Data Science]]''<br />
|<br />
|-<br />
|-<br />
| Oct 4, '''2:45 PM'''<br />
| B119 Van Vleck<br />
| [https://sites.google.com/wisc.edu/nair-anjali/home/ Anjali Nair] (Math)<br />
| ''[[#Oct 4, Anjali Nair|Reconstruction of Reflection Coefficients Using the Phonon Transport Equation]]''<br />
|<br />
|-<br />
|-<br />
| Oct 18, 4 PM<br />
| 6104 Social Sciences<br />
| [https://jasonltorchinsky.github.io/ Jason Tochinsky] (Math)<br />
| ''[[#Oct 18, Jason Torchinsky|Improving the Vertical Remapping Algorithm in the Department of Energy’s Energy Exascale Earth Systems Model]]''<br />
|<br />
|-<br />
|-<br />
| Oct 25, 4 PM,<br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/patricktbardsley/ Patrick Bardsley] (Senior Machine Learning Engineer at [https://www.cirrus.com/ Cirrus Logic])<br />
| ''[[#Oct 25, Patrick Bardsley|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 8, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/libanmohamed496/ Liban Mohamed] (Machine Learning Engineer at [https://www.mitre.org/ MITRE])<br />
| ''[[#Nov 8, Liban Mohamed|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 15, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/kurt-ehlert-320b8397/ Kurt Ehlert] (Trading Strategy Developer at [https://auros.global/about/ Auros])<br />
| ''[[#Nov 15, Kurt Ehlert|Job Talk-Cryptocurrency Trading]]''<br />
|<br />
|-<br />
|-<br />
| Nov 29, 4 PM<br />
| 9th floor lounge<br />
| [https://people.math.wisc.edu/~boakley/ Bryan Oakley] (Math)<br />
| ''[[#Nov 29, Bryan Oakley|Optimal Spatially Dependent Diffusion]]''<br />
|<br />
|-<br />
|-<br />
| Dec 6, 4 PM<br />
| 9th floor lounge<br />
| [https://sites.google.com/view/hongxuchen/ Hongxu Chen] (Math)<br />
| ''[[#Dec 6, Hongxu Chen|Boltzmann equation with Cercignani-Lampis boundary]]''<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== Sept 20, Julia Lindberg===<br />
Polynomial systems arise naturally in many applications in engineering and the sciences. This talk will outline classes of homotopy continuation algorithms used to solve them. I will then describe ways in which structures such as irreducibility, symmetry and sparsity can be used to improve computational speed. The efficacy of these algorithms will be demonstrated on systems in power systems engineering, statistics and optimization<br />
<br />
<br />
=== Sept 27, Wil Cocke ===<br />
I mostly work as a software developer with an emphasis on data science projects dealing with various Command specific projects. The data science life-cycle is fairly consistent across industries: collect, clean, explore, model, interpret, and repeat with a goal of providing insight to the organization. During my talk, I will share some lessons learned for mathematicians interested in transitioning to software development/ data science. <br />
<br />
<br />
=== Oct 4, Anjali Nair ===<br />
The phonon transport equation is used to model heat conduction in solid materials. I will talk about how we use it to solve an inverse problem to reconstruct the thermal reflection coefficient at an interface. This takes the framework of a PDE constrained optimization problem, and I will also mention the stochastic methods used to solve it.<br />
<br />
<br />
=== Oct 18, Jason Torchinsky ===<br />
A vertical Lagrangian coordinate has been used in global climate models for nearly two decades and has several advantages over other discretizations, including reducing the dimensionality of the physical problem. As the Lagrangian surfaces deform over time, it is necessary to accurately and conservatively remap the vertical Lagrangian coordinate back to a fixed Eulerian coordinate. A popular choice of remapping algorithm is the piecewise parabolic method, a modified version of which is used in the atmospheric component of the Department of Energy's Energy Exascale Earth System Model. However, this version of the remapping algorithm creates unwanted noise at the model top and planetary surface for several standard test cases. We explore four alternative modifications to the algorithm and show that the most accurate of these eliminates this noise. <br />
<br />
<br />
=== Oct 25, Patrick Bardsley ===<br />
During the course of a PhD, students typically enter a proverbial `coal mine’ to extract new information about one or more problems, and in the process become a domain expert in a small niche of the technical and scientific world. Upon leaving the academy, unless one lands a job in their niche domain, much of their problem- and domain-specific knowledge is no longer essential. However, mathematics is broad and general, arguably the most general of all scientific disciplines. This fact alone is a mathematician’s greatest asset and ‘leg-up’ when entering the industrial workforce. In this talk, I will discuss some details of my work, both inside and outside of the academy, with the goal of highlighting the skills and concepts that have been the most general and transferable for me. For example, my academic work on hyperbolic inverse problems helped me learn signal processing concepts I now use daily, while my studies on polycrystalline grain growth pushed me to learn thermodynamics, which translated well to the information theory concepts I now utilize. I will also give you some idea of my current day-to-day responsibilities, and close with my thoughts and suggestions on job searches.<br />
<br />
<br />
=== Nov 8, Liban Mohamed ===<br />
I work as a researcher at MITRE, a company that manages R&D contracts (FFRDCs) with federal agencies. I am nominally a machine learning engineer, but my department supports a diverse array of initiatives with the IRS. In this talk I'll give an overview of the FFRDC space, give a sketch of what I work on and how I spend my time, and share my thoughts about navigating the transition from academia to industry.<br />
<br />
<br />
=== Nov 15, Kurt Ehlert ===<br />
After graduating from the UW, I ventured into the world of trading. My first job was at Virtu, a high-frequency market-maker, and currently I work at Auros, which is a high-frequency trading firm that focuses on cryptocurrencies. During the talk, I will give an overview of the industry, job market, and interview process from the perspective of a "quant". Then I will describe the day-to-day work and give a high-level description of typical projects. <br />
<br />
<br />
=== Nov 29, Bryan Oakley ===<br />
The solution to the diffusion equation is known to converge exponentially to its steady state, and the rate is given by the spectral gap of the elliptic operator. Using variational techniques, we will maximize the spectral gap over choices of spatially dependent diffusion functions. Using this characterization, we can obtain bounds on the optimal rate of convergence.<br />
<br />
=== Dec 6, Hongxu Chen ===<br />
Boltzmann equation is a fundamental kinetic equation that describes the dynamics of dilute gas. In this talk I will focus on the boundary value problem of the Boltzmann equation and introduce the Cercignani-Lampis boundary, which is a physical boundary that describes the intermediate reflection law between diffuse reflection and specular reflection. <br />
<br />
<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=22646SIAM Student Chapter Seminar2022-02-03T18:29:14Z<p>Nagreen: /* Spring 2022 */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 4 PM<br />
*'''Where:''' See list of talks below <br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
==Spring 2022==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Feb 7, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person ] Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
|-<br />
| Feb 14, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person ] Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
|-<br />
| Feb 21, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person ] Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
<br />
|}<br />
<br />
== Fall 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Sept 20, 4 PM<br />
| Ingraham 214<br />
| [https://sites.google.com/view/julialindberg/home/ Julia Lindberg] (Electrical and Computer Engineering)<br />
|''[[#Sept 20, Julia Lindberg |Polynomial system solving in applications]]''<br />
|-<br />
|-<br />
| Sept 27, 4 PM, <br />
| Zoom (refreshments and conference call in 307)<br />
| Wil Cocke (Developer for [https://www.arcyber.army.mil/ ARCYBER])<br />
| ''[[#Sept 27, Wil Cocke |Job talk-Software Development/Data Science]]''<br />
|<br />
|-<br />
|-<br />
| Oct 4, '''2:45 PM'''<br />
| B119 Van Vleck<br />
| [https://sites.google.com/wisc.edu/nair-anjali/home/ Anjali Nair] (Math)<br />
| ''[[#Oct 4, Anjali Nair|Reconstruction of Reflection Coefficients Using the Phonon Transport Equation]]''<br />
|<br />
|-<br />
|-<br />
| Oct 18, 4 PM<br />
| 6104 Social Sciences<br />
| [https://jasonltorchinsky.github.io/ Jason Tochinsky] (Math)<br />
| ''[[#Oct 18, Jason Torchinsky|Improving the Vertical Remapping Algorithm in the Department of Energy’s Energy Exascale Earth Systems Model]]''<br />
|<br />
|-<br />
|-<br />
| Oct 25, 4 PM,<br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/patricktbardsley/ Patrick Bardsley] (Senior Machine Learning Engineer at [https://www.cirrus.com/ Cirrus Logic])<br />
| ''[[#Oct 25, Patrick Bardsley|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 8, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/libanmohamed496/ Liban Mohamed] (Machine Learning Engineer at [https://www.mitre.org/ MITRE])<br />
| ''[[#Nov 8, Liban Mohamed|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 15, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/kurt-ehlert-320b8397/ Kurt Ehlert] (Trading Strategy Developer at [https://auros.global/about/ Auros])<br />
| ''[[#Nov 15, Kurt Ehlert|Job Talk-Cryptocurrency Trading]]''<br />
|<br />
|-<br />
|-<br />
| Nov 29, 4 PM<br />
| 9th floor lounge<br />
| [https://people.math.wisc.edu/~boakley/ Bryan Oakley] (Math)<br />
| ''[[#Nov 29, Bryan Oakley|Optimal Spatially Dependent Diffusion]]''<br />
|<br />
|-<br />
|-<br />
| Dec 6, 4 PM<br />
| 9th floor lounge<br />
| [https://sites.google.com/view/hongxuchen/ Hongxu Chen] (Math)<br />
| ''[[#Dec 6, Hongxu Chen|Boltzmann equation with Cercignani-Lampis boundary]]''<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== Sept 20, Julia Lindberg===<br />
Polynomial systems arise naturally in many applications in engineering and the sciences. This talk will outline classes of homotopy continuation algorithms used to solve them. I will then describe ways in which structures such as irreducibility, symmetry and sparsity can be used to improve computational speed. The efficacy of these algorithms will be demonstrated on systems in power systems engineering, statistics and optimization<br />
<br />
<br />
=== Sept 27, Wil Cocke ===<br />
I mostly work as a software developer with an emphasis on data science projects dealing with various Command specific projects. The data science life-cycle is fairly consistent across industries: collect, clean, explore, model, interpret, and repeat with a goal of providing insight to the organization. During my talk, I will share some lessons learned for mathematicians interested in transitioning to software development/ data science. <br />
<br />
<br />
=== Oct 4, Anjali Nair ===<br />
The phonon transport equation is used to model heat conduction in solid materials. I will talk about how we use it to solve an inverse problem to reconstruct the thermal reflection coefficient at an interface. This takes the framework of a PDE constrained optimization problem, and I will also mention the stochastic methods used to solve it.<br />
<br />
<br />
=== Oct 18, Jason Torchinsky ===<br />
A vertical Lagrangian coordinate has been used in global climate models for nearly two decades and has several advantages over other discretizations, including reducing the dimensionality of the physical problem. As the Lagrangian surfaces deform over time, it is necessary to accurately and conservatively remap the vertical Lagrangian coordinate back to a fixed Eulerian coordinate. A popular choice of remapping algorithm is the piecewise parabolic method, a modified version of which is used in the atmospheric component of the Department of Energy's Energy Exascale Earth System Model. However, this version of the remapping algorithm creates unwanted noise at the model top and planetary surface for several standard test cases. We explore four alternative modifications to the algorithm and show that the most accurate of these eliminates this noise. <br />
<br />
<br />
=== Oct 25, Patrick Bardsley ===<br />
During the course of a PhD, students typically enter a proverbial `coal mine’ to extract new information about one or more problems, and in the process become a domain expert in a small niche of the technical and scientific world. Upon leaving the academy, unless one lands a job in their niche domain, much of their problem- and domain-specific knowledge is no longer essential. However, mathematics is broad and general, arguably the most general of all scientific disciplines. This fact alone is a mathematician’s greatest asset and ‘leg-up’ when entering the industrial workforce. In this talk, I will discuss some details of my work, both inside and outside of the academy, with the goal of highlighting the skills and concepts that have been the most general and transferable for me. For example, my academic work on hyperbolic inverse problems helped me learn signal processing concepts I now use daily, while my studies on polycrystalline grain growth pushed me to learn thermodynamics, which translated well to the information theory concepts I now utilize. I will also give you some idea of my current day-to-day responsibilities, and close with my thoughts and suggestions on job searches.<br />
<br />
<br />
=== Nov 8, Liban Mohamed ===<br />
I work as a researcher at MITRE, a company that manages R&D contracts (FFRDCs) with federal agencies. I am nominally a machine learning engineer, but my department supports a diverse array of initiatives with the IRS. In this talk I'll give an overview of the FFRDC space, give a sketch of what I work on and how I spend my time, and share my thoughts about navigating the transition from academia to industry.<br />
<br />
<br />
=== Nov 15, Kurt Ehlert ===<br />
After graduating from the UW, I ventured into the world of trading. My first job was at Virtu, a high-frequency market-maker, and currently I work at Auros, which is a high-frequency trading firm that focuses on cryptocurrencies. During the talk, I will give an overview of the industry, job market, and interview process from the perspective of a "quant". Then I will describe the day-to-day work and give a high-level description of typical projects. <br />
<br />
<br />
=== Nov 29, Bryan Oakley ===<br />
The solution to the diffusion equation is known to converge exponentially to its steady state, and the rate is given by the spectral gap of the elliptic operator. Using variational techniques, we will maximize the spectral gap over choices of spatially dependent diffusion functions. Using this characterization, we can obtain bounds on the optimal rate of convergence.<br />
<br />
=== Dec 6, Hongxu Chen ===<br />
Boltzmann equation is a fundamental kinetic equation that describes the dynamics of dilute gas. In this talk I will focus on the boundary value problem of the Boltzmann equation and introduce the Cercignani-Lampis boundary, which is a physical boundary that describes the intermediate reflection law between diffuse reflection and specular reflection. <br />
<br />
<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=22645SIAM Student Chapter Seminar2022-02-03T18:28:38Z<p>Nagreen: </p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Mondays at 4 PM<br />
*'''Where:''' See list of talks below <br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
==Spring 2022==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Feb 7, 4 PM<br />
| LOCATION<br />
| [HOMEPAGE | Person ] Department<br />
|''[[#DATE, PERSON |TITLE]]''<br />
|-<br />
|-<br />
|}<br />
== Fall 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date and time<br />
!align="left" | location<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Sept 20, 4 PM<br />
| Ingraham 214<br />
| [https://sites.google.com/view/julialindberg/home/ Julia Lindberg] (Electrical and Computer Engineering)<br />
|''[[#Sept 20, Julia Lindberg |Polynomial system solving in applications]]''<br />
|-<br />
|-<br />
| Sept 27, 4 PM, <br />
| Zoom (refreshments and conference call in 307)<br />
| Wil Cocke (Developer for [https://www.arcyber.army.mil/ ARCYBER])<br />
| ''[[#Sept 27, Wil Cocke |Job talk-Software Development/Data Science]]''<br />
|<br />
|-<br />
|-<br />
| Oct 4, '''2:45 PM'''<br />
| B119 Van Vleck<br />
| [https://sites.google.com/wisc.edu/nair-anjali/home/ Anjali Nair] (Math)<br />
| ''[[#Oct 4, Anjali Nair|Reconstruction of Reflection Coefficients Using the Phonon Transport Equation]]''<br />
|<br />
|-<br />
|-<br />
| Oct 18, 4 PM<br />
| 6104 Social Sciences<br />
| [https://jasonltorchinsky.github.io/ Jason Tochinsky] (Math)<br />
| ''[[#Oct 18, Jason Torchinsky|Improving the Vertical Remapping Algorithm in the Department of Energy’s Energy Exascale Earth Systems Model]]''<br />
|<br />
|-<br />
|-<br />
| Oct 25, 4 PM,<br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/patricktbardsley/ Patrick Bardsley] (Senior Machine Learning Engineer at [https://www.cirrus.com/ Cirrus Logic])<br />
| ''[[#Oct 25, Patrick Bardsley|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 8, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/libanmohamed496/ Liban Mohamed] (Machine Learning Engineer at [https://www.mitre.org/ MITRE])<br />
| ''[[#Nov 8, Liban Mohamed|Job Talk-Machine Learning]]''<br />
|<br />
|-<br />
|-<br />
| Nov 15, 4 PM, <br />
| Zoom (refreshments and conference call in 9th floor lounge)<br />
| [https://www.linkedin.com/in/kurt-ehlert-320b8397/ Kurt Ehlert] (Trading Strategy Developer at [https://auros.global/about/ Auros])<br />
| ''[[#Nov 15, Kurt Ehlert|Job Talk-Cryptocurrency Trading]]''<br />
|<br />
|-<br />
|-<br />
| Nov 29, 4 PM<br />
| 9th floor lounge<br />
| [https://people.math.wisc.edu/~boakley/ Bryan Oakley] (Math)<br />
| ''[[#Nov 29, Bryan Oakley|Optimal Spatially Dependent Diffusion]]''<br />
|<br />
|-<br />
|-<br />
| Dec 6, 4 PM<br />
| 9th floor lounge<br />
| [https://sites.google.com/view/hongxuchen/ Hongxu Chen] (Math)<br />
| ''[[#Dec 6, Hongxu Chen|Boltzmann equation with Cercignani-Lampis boundary]]''<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== Sept 20, Julia Lindberg===<br />
Polynomial systems arise naturally in many applications in engineering and the sciences. This talk will outline classes of homotopy continuation algorithms used to solve them. I will then describe ways in which structures such as irreducibility, symmetry and sparsity can be used to improve computational speed. The efficacy of these algorithms will be demonstrated on systems in power systems engineering, statistics and optimization<br />
<br />
<br />
=== Sept 27, Wil Cocke ===<br />
I mostly work as a software developer with an emphasis on data science projects dealing with various Command specific projects. The data science life-cycle is fairly consistent across industries: collect, clean, explore, model, interpret, and repeat with a goal of providing insight to the organization. During my talk, I will share some lessons learned for mathematicians interested in transitioning to software development/ data science. <br />
<br />
<br />
=== Oct 4, Anjali Nair ===<br />
The phonon transport equation is used to model heat conduction in solid materials. I will talk about how we use it to solve an inverse problem to reconstruct the thermal reflection coefficient at an interface. This takes the framework of a PDE constrained optimization problem, and I will also mention the stochastic methods used to solve it.<br />
<br />
<br />
=== Oct 18, Jason Torchinsky ===<br />
A vertical Lagrangian coordinate has been used in global climate models for nearly two decades and has several advantages over other discretizations, including reducing the dimensionality of the physical problem. As the Lagrangian surfaces deform over time, it is necessary to accurately and conservatively remap the vertical Lagrangian coordinate back to a fixed Eulerian coordinate. A popular choice of remapping algorithm is the piecewise parabolic method, a modified version of which is used in the atmospheric component of the Department of Energy's Energy Exascale Earth System Model. However, this version of the remapping algorithm creates unwanted noise at the model top and planetary surface for several standard test cases. We explore four alternative modifications to the algorithm and show that the most accurate of these eliminates this noise. <br />
<br />
<br />
=== Oct 25, Patrick Bardsley ===<br />
During the course of a PhD, students typically enter a proverbial `coal mine’ to extract new information about one or more problems, and in the process become a domain expert in a small niche of the technical and scientific world. Upon leaving the academy, unless one lands a job in their niche domain, much of their problem- and domain-specific knowledge is no longer essential. However, mathematics is broad and general, arguably the most general of all scientific disciplines. This fact alone is a mathematician’s greatest asset and ‘leg-up’ when entering the industrial workforce. In this talk, I will discuss some details of my work, both inside and outside of the academy, with the goal of highlighting the skills and concepts that have been the most general and transferable for me. For example, my academic work on hyperbolic inverse problems helped me learn signal processing concepts I now use daily, while my studies on polycrystalline grain growth pushed me to learn thermodynamics, which translated well to the information theory concepts I now utilize. I will also give you some idea of my current day-to-day responsibilities, and close with my thoughts and suggestions on job searches.<br />
<br />
<br />
=== Nov 8, Liban Mohamed ===<br />
I work as a researcher at MITRE, a company that manages R&D contracts (FFRDCs) with federal agencies. I am nominally a machine learning engineer, but my department supports a diverse array of initiatives with the IRS. In this talk I'll give an overview of the FFRDC space, give a sketch of what I work on and how I spend my time, and share my thoughts about navigating the transition from academia to industry.<br />
<br />
<br />
=== Nov 15, Kurt Ehlert ===<br />
After graduating from the UW, I ventured into the world of trading. My first job was at Virtu, a high-frequency market-maker, and currently I work at Auros, which is a high-frequency trading firm that focuses on cryptocurrencies. During the talk, I will give an overview of the industry, job market, and interview process from the perspective of a "quant". Then I will describe the day-to-day work and give a high-level description of typical projects. <br />
<br />
<br />
=== Nov 29, Bryan Oakley ===<br />
The solution to the diffusion equation is known to converge exponentially to its steady state, and the rate is given by the spectral gap of the elliptic operator. Using variational techniques, we will maximize the spectral gap over choices of spatially dependent diffusion functions. Using this characterization, we can obtain bounds on the optimal rate of convergence.<br />
<br />
=== Dec 6, Hongxu Chen ===<br />
Boltzmann equation is a fundamental kinetic equation that describes the dynamics of dilute gas. In this talk I will focus on the boundary value problem of the Boltzmann equation and introduce the Cercignani-Lampis boundary, which is a physical boundary that describes the intermediate reflection law between diffuse reflection and specular reflection. <br />
<br />
<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Using_a_Ricoh_Printer_on_a_PC&diff=21654Using a Ricoh Printer on a PC2021-09-17T17:30:17Z<p>Nagreen: </p>
<hr />
<div>===Adding the Ricoh Printer===<br />
<br />
Use these instructions.<br />
<br />
[https://sites.google.com/a/wisc.edu/math-intranet/administrative-resources/computing/printing/windows-ip-printing-instructions PC printing setup instructions]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Using_a_Ricoh_Printer_on_a_Macintosh&diff=21653Using a Ricoh Printer on a Macintosh2021-09-17T16:45:35Z<p>Nagreen: </p>
<hr />
<div>Use these instructions on how to setup a printer on a Macintosh.<br />
<br />
[https://sites.google.com/a/wisc.edu/math-intranet/administrative-resources/computing/printing Setting up printing on your Mac]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Using_a_Ricoh_Printer_on_a_Macintosh&diff=21652Using a Ricoh Printer on a Macintosh2021-09-17T16:45:26Z<p>Nagreen: </p>
<hr />
<div>Use these instructions on how to setup a printer on a Macintosh.<br />
<br />
[https://sites.google.com/a/wisc.edu/math-intranet/administrative-resources/computing/printing | Setting up printing on your Mac]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Using_a_Ricoh_Printer_on_a_Macintosh&diff=21651Using a Ricoh Printer on a Macintosh2021-09-17T16:45:06Z<p>Nagreen: </p>
<hr />
<div>Use these instructions on how to setup a printer on a Macintosh.<br />
<br />
[https://sites.google.com/a/wisc.edu/math-intranet/administrative-resources/computing/printing]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=Using_a_Ricoh_Printer_on_a_Macintosh&diff=21650Using a Ricoh Printer on a Macintosh2021-09-17T16:44:48Z<p>Nagreen: </p>
<hr />
<div>Use these instructions on how to setup a printer on a Macintosh.<br />
<br />
https://sites.google.com/a/wisc.edu/math-intranet/administrative-resources/computing/printing</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=21604SIAM Student Chapter Seminar2021-09-15T14:09:09Z<p>Nagreen: </p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' 3:30 pm<br />
*'''Where:''' Zoom <br />
*'''Organizers:''' [https://sites.google.com/wisc.edu/evan-sorensen Evan Sorensen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
== Fall 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|<br />
|<br />
|<br />
|-<br />
|-<br />
|<br />
|<br />
|<br />
|-<br />
|-<br />
|<br />
|<br />
|<br />
|-<br />
|-<br />
|-<br />
|-<br />
|<br />
|<br />
|<br />
|-<br />
|-<br />
|<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar/Fall2020&diff=21603SIAM Student Chapter Seminar/Fall20202021-09-15T14:05:24Z<p>Nagreen: Created page with "== Fall 2020 == {| cellpadding="8" !align="left" | date !align="left" | speaker !align="left" | title |- |9/29 |Yu Feng (Math) |''#9/29, Yu Feng (Math)|Phase separation in..."</p>
<hr />
<div>== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|9/29<br />
|Yu Feng (Math)<br />
|''[[#9/29, Yu Feng (Math)|Phase separation in the advective Cahn--Hilliard equation]]''<br />
|-<br />
|-<br />
|10/14<br />
|Dongyu Chen (WPI)<br />
|''[[#10/14, Yuchen Dong (WPI)|A Half-order Numerical Scheme for Nonlinear SDEs with one-sided Lipschitz Drift and H\:{o}lder Continuous Diffusion Coefficients]]''<br />
|-<br />
|-<br />
|10/28<br />
|Evan Sorensen (math)<br />
|''[[#10/28, Evan Sorenson (math)|Unsupervised data classification via Bayesian inference]]''<br />
|-<br />
|-<br />
|-<br />
|-<br />
|11/23<br />
|Weijie Pang (McMaster University)<br />
|''[[#11/23, Weijie Pang (McMaster University)|Pandemic Model with Asymptomatic Viral Carriers and Health Policy]]''<br />
|-<br />
|-<br />
|<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== 9/29, Yu Feng (Math) ===<br />
'''Phase separation in the advective Cahn--Hilliard equation'''<br />
<br />
The Cahn--Hilliard equation is a classic model of phase separation in binary mixtures that exhibits spontaneous coarsening of the phases. We study the Cahn--Hilliard equation with an imposed advection term in order to model the stirring and eventual mixing of the phases. The main result is that if the imposed advection is sufficiently mixing then no phase separation occurs, and the solution instead converges exponentially to a homogeneous mixed state. The mixing effectiveness of the imposed drift is quantified in terms of the dissipation time of the associated advection-hyperdiffusion equation, and we produce examples of velocity fields with a small dissipation time. We also study the relationship between this quantity and the dissipation time of the standard advection-diffusion equation.<br />
<br />
<br />
=== 10/14, Yuchen Dong (WPI) ===<br />
'''A Half-order Numerical Scheme for Nonlinear SDEs with one-sided Lipschitz Drift and Hölder Continuous Diffusion Coefficients'''<br />
<br />
We consider positivity-preserving explicit schemes for one-dimensional nonlinear stochastic differential<br />
equations. The drift coefficients satisfy the one-sided Lipschitz condition, and the diffusion coefficients<br />
are Hölder continuous. To control the fast growth of moments of solutions, we introduce several explicit<br />
schemes including the tamed and truncated Euler schemes. The fundamental idea is to guarantee the<br />
non-negativity of solutions. The proofs rely on the boundedness for negative moments and exponential of<br />
negative moments. We present several numerical schemes for a modified Cox-Ingersoll-Ross model and a<br />
two-factor Heston model and demonstrate their half-order convergence rate.<br />
<br />
<br />
=== 10/28, Evan Sorensen (math) ===<br />
''' Unsupervised data classification via Bayesian inference'''<br />
<br />
Bayesian inference is a way of “updating” our current state of knowledge given some data. In this talk, I will discuss how one can use Bayesian inference to classify data into separate groups. Particularly, I will discuss an application of this to outlier detection in contamination control within semiconductor manufacturing. Time permitting, I will talk about some computational tools for these models.<br />
<br />
<br />
<br />
=== 11/23, Weijie Pang (McMaster University) ===<br />
<br />
'''Pandemic Model with Asymptomatic Viral Carriers and Health Policy '''<br />
<br />
By October 13, 2020, the total number of COVID-19 confirmed cases had been 37,880,040 with 1,081,857 death in the world. The speed, range and influence of this virus exceed any pandemic in history. To find reasons of this incredible fast spread, we introduce asymptomatic category into a SEIR pandemic model. Based on published data of Italy, we calibrated exposed rates of COVID-19 in this model and then simulated the spread of COVID-19 for different asymptomatic rates. To measure the effects of different types of public health policies on this pandemic, we construct a pandemic model including health policies. By the simulation of this model, we provide feasible suggestions of containment to regulators. <br />
<br />
<br />
<br />
<br></div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=21602SIAM Student Chapter Seminar2021-09-15T14:05:18Z<p>Nagreen: /* Past Semesters */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' 3:30 pm<br />
*'''Where:''' Zoom <br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|9/29<br />
|Yu Feng (Math)<br />
|''[[#9/29, Yu Feng (Math)|Phase separation in the advective Cahn--Hilliard equation]]''<br />
|-<br />
|-<br />
|10/14<br />
|Dongyu Chen (WPI)<br />
|''[[#10/14, Yuchen Dong (WPI)|A Half-order Numerical Scheme for Nonlinear SDEs with one-sided Lipschitz Drift and H\:{o}lder Continuous Diffusion Coefficients]]''<br />
|-<br />
|-<br />
|10/28<br />
|Evan Sorensen (math)<br />
|''[[#10/28, Evan Sorenson (math)|Unsupervised data classification via Bayesian inference]]''<br />
|-<br />
|-<br />
|-<br />
|-<br />
|11/23<br />
|Weijie Pang (McMaster University)<br />
|''[[#11/23, Weijie Pang (McMaster University)|Pandemic Model with Asymptomatic Viral Carriers and Health Policy]]''<br />
|-<br />
|-<br />
|<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== 9/29, Yu Feng (Math) ===<br />
'''Phase separation in the advective Cahn--Hilliard equation'''<br />
<br />
The Cahn--Hilliard equation is a classic model of phase separation in binary mixtures that exhibits spontaneous coarsening of the phases. We study the Cahn--Hilliard equation with an imposed advection term in order to model the stirring and eventual mixing of the phases. The main result is that if the imposed advection is sufficiently mixing then no phase separation occurs, and the solution instead converges exponentially to a homogeneous mixed state. The mixing effectiveness of the imposed drift is quantified in terms of the dissipation time of the associated advection-hyperdiffusion equation, and we produce examples of velocity fields with a small dissipation time. We also study the relationship between this quantity and the dissipation time of the standard advection-diffusion equation.<br />
<br />
<br />
=== 10/14, Yuchen Dong (WPI) ===<br />
'''A Half-order Numerical Scheme for Nonlinear SDEs with one-sided Lipschitz Drift and Hölder Continuous Diffusion Coefficients'''<br />
<br />
We consider positivity-preserving explicit schemes for one-dimensional nonlinear stochastic differential<br />
equations. The drift coefficients satisfy the one-sided Lipschitz condition, and the diffusion coefficients<br />
are Hölder continuous. To control the fast growth of moments of solutions, we introduce several explicit<br />
schemes including the tamed and truncated Euler schemes. The fundamental idea is to guarantee the<br />
non-negativity of solutions. The proofs rely on the boundedness for negative moments and exponential of<br />
negative moments. We present several numerical schemes for a modified Cox-Ingersoll-Ross model and a<br />
two-factor Heston model and demonstrate their half-order convergence rate.<br />
<br />
<br />
=== 10/28, Evan Sorensen (math) ===<br />
''' Unsupervised data classification via Bayesian inference'''<br />
<br />
Bayesian inference is a way of “updating” our current state of knowledge given some data. In this talk, I will discuss how one can use Bayesian inference to classify data into separate groups. Particularly, I will discuss an application of this to outlier detection in contamination control within semiconductor manufacturing. Time permitting, I will talk about some computational tools for these models.<br />
<br />
<br />
<br />
=== 11/23, Weijie Pang (McMaster University) ===<br />
<br />
'''Pandemic Model with Asymptomatic Viral Carriers and Health Policy '''<br />
<br />
By October 13, 2020, the total number of COVID-19 confirmed cases had been 37,880,040 with 1,081,857 death in the world. The speed, range and influence of this virus exceed any pandemic in history. To find reasons of this incredible fast spread, we introduce asymptomatic category into a SEIR pandemic model. Based on published data of Italy, we calibrated exposed rates of COVID-19 in this model and then simulated the spread of COVID-19 for different asymptomatic rates. To measure the effects of different types of public health policies on this pandemic, we construct a pandemic model including health policies. By the simulation of this model, we provide feasible suggestions of containment to regulators. <br />
<br />
<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreenhttps://wiki.math.wisc.edu/index.php?title=SIAM_Student_Chapter_Seminar&diff=21601SIAM Student Chapter Seminar2021-09-15T14:04:59Z<p>Nagreen: </p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' 3:30 pm<br />
*'''Where:''' Zoom <br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|9/29<br />
|Yu Feng (Math)<br />
|''[[#9/29, Yu Feng (Math)|Phase separation in the advective Cahn--Hilliard equation]]''<br />
|-<br />
|-<br />
|10/14<br />
|Dongyu Chen (WPI)<br />
|''[[#10/14, Yuchen Dong (WPI)|A Half-order Numerical Scheme for Nonlinear SDEs with one-sided Lipschitz Drift and H\:{o}lder Continuous Diffusion Coefficients]]''<br />
|-<br />
|-<br />
|10/28<br />
|Evan Sorensen (math)<br />
|''[[#10/28, Evan Sorenson (math)|Unsupervised data classification via Bayesian inference]]''<br />
|-<br />
|-<br />
|-<br />
|-<br />
|11/23<br />
|Weijie Pang (McMaster University)<br />
|''[[#11/23, Weijie Pang (McMaster University)|Pandemic Model with Asymptomatic Viral Carriers and Health Policy]]''<br />
|-<br />
|-<br />
|<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== 9/29, Yu Feng (Math) ===<br />
'''Phase separation in the advective Cahn--Hilliard equation'''<br />
<br />
The Cahn--Hilliard equation is a classic model of phase separation in binary mixtures that exhibits spontaneous coarsening of the phases. We study the Cahn--Hilliard equation with an imposed advection term in order to model the stirring and eventual mixing of the phases. The main result is that if the imposed advection is sufficiently mixing then no phase separation occurs, and the solution instead converges exponentially to a homogeneous mixed state. The mixing effectiveness of the imposed drift is quantified in terms of the dissipation time of the associated advection-hyperdiffusion equation, and we produce examples of velocity fields with a small dissipation time. We also study the relationship between this quantity and the dissipation time of the standard advection-diffusion equation.<br />
<br />
<br />
=== 10/14, Yuchen Dong (WPI) ===<br />
'''A Half-order Numerical Scheme for Nonlinear SDEs with one-sided Lipschitz Drift and Hölder Continuous Diffusion Coefficients'''<br />
<br />
We consider positivity-preserving explicit schemes for one-dimensional nonlinear stochastic differential<br />
equations. The drift coefficients satisfy the one-sided Lipschitz condition, and the diffusion coefficients<br />
are Hölder continuous. To control the fast growth of moments of solutions, we introduce several explicit<br />
schemes including the tamed and truncated Euler schemes. The fundamental idea is to guarantee the<br />
non-negativity of solutions. The proofs rely on the boundedness for negative moments and exponential of<br />
negative moments. We present several numerical schemes for a modified Cox-Ingersoll-Ross model and a<br />
two-factor Heston model and demonstrate their half-order convergence rate.<br />
<br />
<br />
=== 10/28, Evan Sorensen (math) ===<br />
''' Unsupervised data classification via Bayesian inference'''<br />
<br />
Bayesian inference is a way of “updating” our current state of knowledge given some data. In this talk, I will discuss how one can use Bayesian inference to classify data into separate groups. Particularly, I will discuss an application of this to outlier detection in contamination control within semiconductor manufacturing. Time permitting, I will talk about some computational tools for these models.<br />
<br />
<br />
<br />
=== 11/23, Weijie Pang (McMaster University) ===<br />
<br />
'''Pandemic Model with Asymptomatic Viral Carriers and Health Policy '''<br />
<br />
By October 13, 2020, the total number of COVID-19 confirmed cases had been 37,880,040 with 1,081,857 death in the world. The speed, range and influence of this virus exceed any pandemic in history. To find reasons of this incredible fast spread, we introduce asymptomatic category into a SEIR pandemic model. Based on published data of Italy, we calibrated exposed rates of COVID-19 in this model and then simulated the spread of COVID-19 for different asymptomatic rates. To measure the effects of different types of public health policies on this pandemic, we construct a pandemic model including health policies. By the simulation of this model, we provide feasible suggestions of containment to regulators. <br />
<br />
<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*[[SIAM_Student_Chapter_Seminar/Fall2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Nagreen