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In 2022-2023, our colloquia will be in-person talks in B239 unless otherwise stated.


==September 9 , 2022, Friday at 4pm  [https://math.ou.edu/~jing/ Jing Tao] (University of Oklahoma)==
<b>UW-Madison Mathematics Colloquium is on Fridays at 4:00 pm in Van Vleck B239 unless otherwise noted.</b>
(host: Dymarz, Uyanik, WIMAW)


'''On surface homeomorphisms'''
Contacts for the colloquium are Michael Kemeny (spring) and Dallas Albritton (fall).


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.
Everyone in the math department is subscribed to the mathcolloquium@g-groups.wisc.edu mailing list.
==September 23, 2022, Friday at 4pm  [https://www.pabloshmerkin.org/ Pablo Shmerkin] (University of British Columbia) ==
(host: Guo, Seeger)


'''Incidences and line counting: from the discrete to the fractal setting'''


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.
This semester's colloquia: [[Colloquia/Spring 2025|Spring 2025]]
==Future Colloquia==
==Past Colloquia ==


==September 30, 2022, Friday at 4pm [https://alejandraquintos.com/ Alejandra Quintos] (University of Wisconsin-Madison) ==
[[Colloquia/Fall 2024|Fall 2024]]
(host: Stovall)


'''Dependent Stopping Times and an Application to Credit Risk Theory'''
[[Colloquia/Spring2024|Spring 2024]]


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.
[[Colloquia/Fall 2023|Fall 2023]]


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.
[[Colloquia/Spring2023|Spring 2023]]
==October 7, 2022, Friday at 4pm  [https://www.daniellitt.com/ Daniel Litt] (University of Toronto)==
(host: Ananth Shankar)
 
==October 14, 2022, Friday at 4pm  [https://math.sciences.ncsu.edu/people/asagema/ Andrew Sageman-Furnas] (North Carolina State)==
(host: Mari-Beffa)
 
==October 21, 2022, Friday at 4pm  [https://web.ma.utexas.edu/users/ntran/ Ngoc Mai Tran] (Texas)==
(host: Rodriguez)
== November 7-9, 2022, [https://ai.facebook.com/people/kristin-lauter/ Kristen Lauter] (Facebook) ==
Distinguished lectures
 
(host: Yang).
 
== November 11, 2022, Friday at 4pm [http://users.cms.caltech.edu/~jtropp/ Joel Tropp] (Caltech)==
This is the Annual LAA lecture. See [https://math.wisc.edu/laa-lecture/ this] for its history.
 
(host: Qin, Jordan)
==November 18, 2022, Friday at 4pm  [TBD]==
(reserved by HC. contact: Stechmann)
==December 2, 2022, Friday at 4pm  [TBD]==
(reserved by HC. contact: Stechmann)
==December 9, 2022, Friday at 4pm  [TBD]==
(reserved by HC. contact: Stechmann)
== Future Colloquia ==


[[Colloquia/Fall2022|Fall 2022]]
[[Colloquia/Fall2022|Fall 2022]]


[[Colloquia/Spring2023|Spring 2023]]
== Past Colloquia ==
[[Spring 2022 Colloquiums|Spring 2022]]
[[Spring 2022 Colloquiums|Spring 2022]]



Latest revision as of 06:22, 17 December 2024


UW-Madison Mathematics Colloquium is on Fridays at 4:00 pm in Van Vleck B239 unless otherwise noted.

Contacts for the colloquium are Michael Kemeny (spring) and Dallas Albritton (fall).

Everyone in the math department is subscribed to the mathcolloquium@g-groups.wisc.edu mailing list.


This semester's colloquia: Spring 2025

Future Colloquia

Past Colloquia

Fall 2024

Spring 2024

Fall 2023

Spring 2023

Fall 2022

Spring 2022

Fall 2021

Spring 2021

Fall 2020

Spring 2020

Fall 2019

Spring 2019

Fall 2018

Spring 2018

Fall 2017

Spring 2017

Fall 2016

Spring 2016

Fall 2015

Spring 2015

Fall 2014

Spring 2014

Fall 2013

Spring 2013

Fall 2012

WIMAW