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* '''When:''' Mondays 3:30-4:30 PM
* '''When:''' Mondays 3:30-4:30 PM
* '''Where:''' Van Vleck B139
* '''Where:''' Van Vleck B235
* '''Organizers:''' Karthik Ravishankar and [https://sites.google.com/wisc.edu/antonio Antonio Nakid Cordero]
* '''Organizer:''' Mariya Soskova


The talk schedule is arranged at the beginning of each semester. If you would like to participate, please contact one of the organizers.
The talk schedule is arranged at the beginning of each semester. If you would like to participate, please contact the organizers.


Sign up for the graduate logic seminar mailing list:  join-grad-logic-sem@lists.wisc.edu
<!--Sign up for the graduate logic seminar mailing list:  [mailto:join-grad-logic-sem@lists.wisc.edu join-grad-logic-sem@lists.wisc.edu]-->


== Fall 2022 ==
== Spring 2025 ==


=== September 12 - Organizational Meeting ===
The seminar will be run as a 1-credit seminar Math 975. In Spring 2025, we will finish last semester's topic on Higher Computability Theory.Once we are done students will present a logic topic of their choice (it could be original work, but does not have to be).  If you are not enrolled but would like to audit it, please contact [mailto:soskova@wisc.edu Mariya Soskova].


We will meet to assign speakers to dates.
Presentation Schedule: [https://docs.google.com/spreadsheets/d/1uRSaI1edJ5sepz57NV07ohIfBSKL9FgkvJvMAewk1ms/edit?usp=sharing Sign up here.]


=== '''September 19 - Karthik Ravishankar''' ===
Notes on Higher Computability Theory: [https://uwmadison.box.com/s/j3xftdj1i70d4lblxhzswhg9e25ajcpq Download the notes here.] You will need your UW-login. Please, do not distribute these notes without permission from the author.
'''Title:''' Lowness for Isomorphism ([https://wiki.math.wisc.edu/images/Karthik_talk.pdf Slides])


'''Abstract:''' A Turing degree is said to be low for isomorphism if it can only compute an isomorphism between computable structures only when a computable isomorphism already exists. In this talk, we show that the measure of the class of low for isomorphism sets in Cantor space is 0 and that no Martin Lof random is low for isomorphism.
<!--Zoom link for remote attendance: https://uwmadison.zoom.us/j/96168027763?pwd=bGdvL3lpOGl6QndQcG5RTFUzY3JXQT09 (Meeting ID: 961 6802 7763, Password: 975f23)-->


=== '''September 26 - Antonio Nakid Cordero''' ===
=== '''January 27 - Organizational Meeting and Sapir Ben-Shahar''' ===
'''Title:''' When Models became Polish: an introduction to the Topological Vaught Conjecture ([[Media:GradLogSem - Topological Vaught Conjecture.pdf|Slides]])


'''Abstract:''' Vaught's Conjecture, originally asked by Vaught in 1961, is one of the most (in)famous open problems in mathematical logic. The conjecture is that a complete theory on a countable language must either have countably-many or continuum-many non-isomorphic models. In this talk, we will discuss some of the main ideas that surround this conjecture, with special emphasis on a topological generalization in terms of the continuous actions of Polish groups.
Mariya Soskova will call for volunteers to sign up for presentations.  


=== '''October 10 - Yunting Zhang''' ===
Sapir Ben-Shahar will wrap up Section 5.1
'''Title:''' Some History of Logic ([[Media:Godel.pdf|Slides]])


'''Abstract:''' The lives of great thinkers are sometimes overshadowed by their achievements-and there is perhaps no better illustration of this phenomenon than the life and work of Gödel. Take a look at Gödel's own timeline and see how wars and other mathematicians influenced him.
=== '''February 3 -  Taeyoung Em''' ===


=== '''October 17 - Alice Vidrine''' ===
Taeyoung Em will present Section 5.3.  
'''Title:''' Local operators, bilayer Turing reducibility, and enumeration Weihrauch degrees ([[Media:LTeW-talk.pdf|Slides]])


'''Abstract:''' Realizability toposes have a rich variety of subtoposes, corresponding to their local operators. These local operators are somewhat difficult to study in their usual form, which seems far removed from the usual objects of computability theoretic study. Recent work by Takayuki Kihara has given a characterization of the local operators on the effective topos in computability theoretic terms related to Weihrauch reduction, and which generalizes to several other realizability toposes of possible interest to computability theorists. This narrative-focused talk outlines what a realizability topos looks like, what local operators are, what Kihara's bilayer Turing reduction looks like, and how this leads to preliminary questions about a relative of the Weihrauch degrees based on enumeration reduction.
=== '''February 10 -  Hongyu Zhu''' ===


=== '''October 24 - Hongyu Zhu''' ===
Hongyu Zhu will present Section 5.3
'''Title:''' Investigating Natural Theories through the Consistency Operator ([[Media:ConsistencyOperator.pdf|Slides]])


'''Abstract:''' The phenomenon that "natural" theories tend to be linearly ordered in terms of consistency strength is a long-standing mystery. One approach to solving the problem is Martin's Conjecture, which roughly claims that the only natural functions on the Turing degrees are transfinite iterates of the Turing jump. In this talk we will focus on a similar approach, working inside the Lindenbaum algebra of elementary arithmetic instead of the Turing degrees. Here, the consistency operator takes the role of the jump. We will see that while some nice analogous claims can be established, there are also counterexamples that prevent us from strengthening the results in various ways.
=== '''February 17 -  Karthik Ravishankar''' ===


=== '''October 31 - Break for Halloween''' ===
'''Title:''' Strong minimal covers and the cupping property


=== '''November 7 - John Spoerl''' ===
'''Abstract:''' A longstanding question in degree theory has been whether every minimal Turing degree has a strong minimal cover. Meanwhile a strong example of degrees without SMC's are those which have the cupping property. It is known that PA degrees have the cupping property, as do degrees with a certain amount of escaping power. On the other hand, it is known that being weak in the sense of being non DNC and Hyperimmune-free lets you have a SMC. Degrees with the cupping property are closed upwards while it is not known if degrees with SMC are closed downwards.  It is also not known if every degree either has the cupping property or a SMC. In this talk we will review several of these results and present techniques used to build SMCs.
'''Title:''' Universal Algorithms


'''Abstract:''' Among the many ways we can flex Gödel’s Incompleteness theorems, there is one that feels especially strange: there is a partial computable function F, such that F gives no output in the standard model of arithmetic, but for any function G on natural numbers (computable or not) there is a non-standard model in which F behaves exactly as G. I’ll discuss some related arguments and some philosophical questions this may raise about our notions of finiteness and determinism.
=== '''February 24 -  Hongyu Zhu''' ===


=== '''November 14 - Josiah Jacobsen-Grocott''' ===
'''Title:''' Seeing the forest does not account for the trees
'''Title:''' The Paris-Harrington Theorem


'''Abstract:''' In this talk, I will present the proof of the Paris-Harrington theorem. The
'''Abstract:''' Say a first-order theory (or a type) has bounded axiomatization if it has an axiomatization by <math>\forall_n</math>-formulas for some finite n. In this talk, we will discuss basic properties of theories and types with (or without) bounded axiomatizations, and in particular whether boundedness of theories implies that of types. (The meaning of the title will be explained in due time.)
Paris-Harrington theorem states that over PA the consistency of Peano arithmetic is equivalent to
a strengthening of the finite Ramsey theorem. This was the first example of a result from "ordinary
mathematics" that can not be proven by PA. The aim of this talk is to cover the main logical
steps in this proof and give some of the combinatorics.


=== '''November 21 - Karthik Ravishankar''' ===
=== '''March 3 - Uri Andrews''' ===
'''Title:''' The computing power of Baire space vs Cantor Space


'''Abstract:''' Generic Muchnik reducibility extends the notion of Muchnik reducibility to the uncountable setting. In this talk we'll look at some recent work which comes up with another technique of constructing a structure of degree strictly between Cantor space and Baire Space. We'll see that there is a generic copy of Cantor space which computes no escaping function while every copy of Baire space computes a dominating function. We then construct a structure of intermediate degree which always computes an escaping function but no dominating function.
'''Title:''' On the spectra of computable models of disintegrated strongly minimal theories with bounded ranks


=== '''November 28 - Logan Heath''' ===
'''Abstract:''' The spectrum of a strongly minimal theory characterizes which of its countable models have computable copies (indexed by their dimensions). We will focus on the disintegrated strongly minimal theories, i.e., where the algebraic closure of a set is the union of the algebraic closures of the elements of the set.
'''Title''': A Mathematical Analysis of Theories of Generative Grammar: The Peters-Ritchie Theorem


'''Abstract''': This is a preview of a talk intended primarily for undergraduate students in linguistics who have just completed a first course in syntax. The goal of the talk is to spark interest in applications of mathematical techniques to the study of theories of syntax. We will focus on the Peters-Ritchie Theorem which shows that transformational grammars can generate languages which are c.e., but not computable.
Somewhere in the late aughts, Alice Medvedev and I proved that if a theory is disintegrated strongly minimal and has a finite signature, then either all models are computable, no models are computable, or only the prime model is computable. Steffen Lempp and I tried to push this sort of analysis past finite signatures and we have results about theories which are disintegrated strongly minimal and every symbol in the (infinite) signature has rank less than or equal to 1 in the theory (i.e., you cannot have R(a,b,\bar{z}) if a and b are algebraically independent). Over this past winter break, I found a strategy to bring (some of) this analysis to strongly minimal theories in infinite languages as long as there is some finite N so that every symbol has rank less than or equal to N. I'll describe this strategy, and depending on time, I might even present something that loosely resembles a proof.


=== '''December 5 - Logan Heath''' ===
=== '''March 10 - Logan Heath''' ===


=== '''December 12 - Yuxiao Fu''' ===
'''Title:''' Degree Spectra of Theories
 
'''Abstract:''' I will discuss the notion of the degree spectrum of a theory, introduce a class of questions one might ask about such a thing, point to a few of the answers to such questions, and look a little more closely at one such spectrum to highlight the sorts of techniques that arise in the area.
 
 
=== '''March 17 -  Yiqing Wang''' ===
 
'''Title:''' tba
 
'''Abstract:''' tba
 
=== '''March 31 -  Chiara Travesset''' ===
 
'''Title:''' tba
 
'''Abstract:''' tba
 
=== '''April 21 -  Ang Li???''' ===
 
'''Title:''' tba
 
'''Abstract:''' tba
 
 
== Fall 2024 ==
 
The seminar will be run as a 1-credit seminar Math 975 . In Fall 2024, the topic will be Higher Computability Theory. We will follow notes by Noam Greenberg. If you are not enrolled but would like to audit it, please contact [mailto:soskova@wisc.edu Mariya Soskova].
 
Presentation Schedule: [https://docs.google.com/spreadsheets/d/1ect-dgHdoHOgq4-5BGFiDh6pPThLfDg69Yg__-b_5RY/edit?usp=sharing Sign up here.]
 
Notes: [https://uwmadison.box.com/s/j3xftdj1i70d4lblxhzswhg9e25ajcpq Download the notes here.] You will need your UW-login. Please, do not distribute these notes without permission from the author.
 
<!--Zoom link for remote attendance: https://uwmadison.zoom.us/j/96168027763?pwd=bGdvL3lpOGl6QndQcG5RTFUzY3JXQT09 (Meeting ID: 961 6802 7763, Password: 975f23)-->
 
=== '''September 9 - Organizational Meeting''' ===
 
Mariya Soskova will start with the first sections from the notes.
 
We will then assign speakers to dates and topics.
 
=== '''September 16 -  Sections 1.2-1.4''' ===
 
Kanav Madhura will continue with Sections 1.2-1.4.
 
=== '''September 23 -  Sections 1.3-1.4 and 2.1-2.2''' ===
 
Kanav Madhura will continue with Sections 1.3-1.4. Lucas Duckworth will be ready with Sections 2.1 and 2.2 should there be time.
 
=== '''September 30 -  Sections 2.2 and 2.3-2.5''' ===
 
Lucas Duckworth will finish Section 2.2. Karthik Ravishankar will begin 2.3, 2.4, and 2.5.
=== '''October 7th -  Sections 2.4 and 2.5''' ===
 
Karthik Ravishankar will  finish, 2.4, and 2.5.  Liang Yu will give a talk at 4:00pm.
 
=== '''October 14th -  Sections 2.6 and 2.7''' ===
 
Bjarki Gunnarsson  will present Sections 2.6 and 2.7
 
=== '''October 21th -  Section 3.1''' ===
 
Karthik Ravishankar will present Section 3.1 
 
=== '''October 28th -  Sections 3.2 and 3.3''' ===
 
Karthik Ravishankar will finish Sections 3.2  and John Spoerl will begin Section 3.3
 
=== '''November 4th -  Sections 3.3 and 3.4''' ===
 
John Spoerl will finish Sections 3.3 and 3.4
 
=== '''November 11th -  Section 4.1''' ===
 
Antonion Nakid-Cordero will present Section 4.1
 
=== '''November 19th -  Sections 4.1 and 4.2''' ===
 
Start 4:00PM in VV901! Antonion Nakid-Cordero will continue with Section 4.1, Ang Li will begin Section 4.2.
 
 
=== '''November 25th -  Sections 4.2 and 4.3''' ===
 
Back to the usual time and place. Ang Li will begin Section 4.2.
 
=== '''December 2nd - Section 4.3''' ===
 
Ang Li will present Section 4.3.
 
=== '''December 9nd -  Section 5.1''' ===
 
Last seminar for this semester. Sapir Ben-Shahar will begin Section 5.1
 
<!-- Template
 
=== '''September 18 - xxx''' ===
'''Title:''' TBA ([https://wiki.math.wisc.edu/images/***.pdf Slides])
 
'''Abstract:''' TBA
 
-->


== Previous Years ==
== Previous Years ==


The schedule of talks from past semesters can be found [[Graduate Logic Seminar, previous semesters|here]].
The schedule of talks from past semesters can be found [[Graduate Logic Seminar, previous semesters|here]].

Latest revision as of 17:24, 10 March 2025

The Graduate Logic Seminar is an informal space where graduate students and professors present topics related to logic which are not necessarily original or completed work. This is a space focused principally on practicing presentation skills or learning materials that are not usually presented in a class.

  • When: Mondays 3:30-4:30 PM
  • Where: Van Vleck B235
  • Organizer: Mariya Soskova

The talk schedule is arranged at the beginning of each semester. If you would like to participate, please contact the organizers.


Spring 2025

The seminar will be run as a 1-credit seminar Math 975. In Spring 2025, we will finish last semester's topic on Higher Computability Theory.Once we are done students will present a logic topic of their choice (it could be original work, but does not have to be). If you are not enrolled but would like to audit it, please contact Mariya Soskova.

Presentation Schedule: Sign up here.

Notes on Higher Computability Theory: Download the notes here. You will need your UW-login. Please, do not distribute these notes without permission from the author.


January 27 - Organizational Meeting and Sapir Ben-Shahar

Mariya Soskova will call for volunteers to sign up for presentations.

Sapir Ben-Shahar will wrap up Section 5.1

February 3 - Taeyoung Em

Taeyoung Em will present Section 5.3.

February 10 - Hongyu Zhu

Hongyu Zhu will present Section 5.3

February 17 - Karthik Ravishankar

Title: Strong minimal covers and the cupping property

Abstract: A longstanding question in degree theory has been whether every minimal Turing degree has a strong minimal cover. Meanwhile a strong example of degrees without SMC's are those which have the cupping property. It is known that PA degrees have the cupping property, as do degrees with a certain amount of escaping power. On the other hand, it is known that being weak in the sense of being non DNC and Hyperimmune-free lets you have a SMC. Degrees with the cupping property are closed upwards while it is not known if degrees with SMC are closed downwards. It is also not known if every degree either has the cupping property or a SMC. In this talk we will review several of these results and present techniques used to build SMCs.

February 24 - Hongyu Zhu

Title: Seeing the forest does not account for the trees

Abstract: Say a first-order theory (or a type) has bounded axiomatization if it has an axiomatization by [math]\displaystyle{ \forall_n }[/math]-formulas for some finite n. In this talk, we will discuss basic properties of theories and types with (or without) bounded axiomatizations, and in particular whether boundedness of theories implies that of types. (The meaning of the title will be explained in due time.)

March 3 - Uri Andrews

Title: On the spectra of computable models of disintegrated strongly minimal theories with bounded ranks

Abstract: The spectrum of a strongly minimal theory characterizes which of its countable models have computable copies (indexed by their dimensions). We will focus on the disintegrated strongly minimal theories, i.e., where the algebraic closure of a set is the union of the algebraic closures of the elements of the set.

Somewhere in the late aughts, Alice Medvedev and I proved that if a theory is disintegrated strongly minimal and has a finite signature, then either all models are computable, no models are computable, or only the prime model is computable. Steffen Lempp and I tried to push this sort of analysis past finite signatures and we have results about theories which are disintegrated strongly minimal and every symbol in the (infinite) signature has rank less than or equal to 1 in the theory (i.e., you cannot have R(a,b,\bar{z}) if a and b are algebraically independent). Over this past winter break, I found a strategy to bring (some of) this analysis to strongly minimal theories in infinite languages as long as there is some finite N so that every symbol has rank less than or equal to N. I'll describe this strategy, and depending on time, I might even present something that loosely resembles a proof.

March 10 - Logan Heath

Title: Degree Spectra of Theories

Abstract: I will discuss the notion of the degree spectrum of a theory, introduce a class of questions one might ask about such a thing, point to a few of the answers to such questions, and look a little more closely at one such spectrum to highlight the sorts of techniques that arise in the area.


March 17 - Yiqing Wang

Title: tba

Abstract: tba

March 31 - Chiara Travesset

Title: tba

Abstract: tba

April 21 - Ang Li???

Title: tba

Abstract: tba


Fall 2024

The seminar will be run as a 1-credit seminar Math 975 . In Fall 2024, the topic will be Higher Computability Theory. We will follow notes by Noam Greenberg. If you are not enrolled but would like to audit it, please contact Mariya Soskova.

Presentation Schedule: Sign up here.

Notes: Download the notes here. You will need your UW-login. Please, do not distribute these notes without permission from the author.


September 9 - Organizational Meeting

Mariya Soskova will start with the first sections from the notes.

We will then assign speakers to dates and topics.

September 16 - Sections 1.2-1.4

Kanav Madhura will continue with Sections 1.2-1.4.

September 23 - Sections 1.3-1.4 and 2.1-2.2

Kanav Madhura will continue with Sections 1.3-1.4. Lucas Duckworth will be ready with Sections 2.1 and 2.2 should there be time.

September 30 - Sections 2.2 and 2.3-2.5

Lucas Duckworth will finish Section 2.2. Karthik Ravishankar will begin 2.3, 2.4, and 2.5.

October 7th - Sections 2.4 and 2.5

Karthik Ravishankar will finish, 2.4, and 2.5. Liang Yu will give a talk at 4:00pm.

October 14th - Sections 2.6 and 2.7

Bjarki Gunnarsson will present Sections 2.6 and 2.7

October 21th - Section 3.1

Karthik Ravishankar will present Section 3.1

October 28th - Sections 3.2 and 3.3

Karthik Ravishankar will finish Sections 3.2 and John Spoerl will begin Section 3.3

November 4th - Sections 3.3 and 3.4

John Spoerl will finish Sections 3.3 and 3.4

November 11th - Section 4.1

Antonion Nakid-Cordero will present Section 4.1

November 19th - Sections 4.1 and 4.2

Start 4:00PM in VV901! Antonion Nakid-Cordero will continue with Section 4.1, Ang Li will begin Section 4.2.


November 25th - Sections 4.2 and 4.3

Back to the usual time and place. Ang Li will begin Section 4.2.

December 2nd - Section 4.3

Ang Li will present Section 4.3.

December 9nd - Section 5.1

Last seminar for this semester. Sapir Ben-Shahar will begin Section 5.1


Previous Years

The schedule of talks from past semesters can be found here.

Retrieved from "https://wiki.math.wisc.edu/index.php?title=Graduate_Logic_Seminar&oldid=28277"