Difference between revisions of "Graduate Logic Seminar"

From UW-Math Wiki
Jump to: navigation, search
(Spring 2021 - Tentative schedule)
 
(13 intermediate revisions by 2 users not shown)
Line 1: Line 1:
 
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.
 
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:''' TBA
+
* '''When:''' Tuesdays 4-5 PM
* '''Where:''' on line (ask for code).
+
* '''Where:''' Van Vleck 901
 
* '''Organizers:''' [https://www.math.wisc.edu/~jgoh/ Jun Le Goh]
 
* '''Organizers:''' [https://www.math.wisc.edu/~jgoh/ Jun Le Goh]
  
Line 9: Line 9:
 
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:  join-grad-logic-sem@lists.wisc.edu
  
== Spring 2021 - Tentative schedule ==
+
== Fall 2021 tentative schedule ==
  
=== February 16 3:30PM - Short talk by Sarah Reitzes (University of Chicago) ===
+
To see what's happening in the Logic qual preparation sessions click [[Logic Qual Prep|here]].
  
Title: Reduction games over $\mathrm{RCA}_0$
+
=== September 14 - organizational meeting ===
  
Abstract: In this talk, I will discuss joint work with Damir D. Dzhafarov and Denis R. Hirschfeldt. Our work centers on the characterization of problems P and Q such that P $\leq_{\omega}$ Q, as well as problems P and Q such that $\mathrm{RCA}_0 \vdash$ Q $\to$ P, in terms of winning strategies in certain games. These characterizations were originally introduced by Hirschfeldt and Jockusch. I will discuss extensions and generalizations of these characterizations, including a certain notion of compactness that allows us, for strategies satisfying particular conditions, to bound the number of moves it takes to win. This bound is independent of the instance of the problem P being considered. This allows us to develop the idea of Weihrauch and generalized Weihrauch reduction over some base theory. Here, we will focus on the base theory $\mathrm{RCA}_0$. In this talk, I will explore these notions of reduction among various principles, including bounding and induction principles.
+
We met to discuss the schedule.
  
=== March 23 4:15PM - Steffen Lempp ===
+
=== September 28 - Ouyang Xiating ===
  
Title: Degree structures and their finite substructures
+
Title: First-order logic, database and consistent query answering
  
Abstract: Many problems in mathematics can be viewed as being coded by sets of natural numbers (as indices).
+
Abstract: Databases are a crucial component of many (if not all) modern
One can then define the relative computability of sets of natural numbers in various ways, each leading to a precise notion of “degree” of a problem (or set).
+
applications. In reality, the data stored are often dirty and contain
In each case, these degrees form partial orders, which can be studied as algebraic structures.
+
duplicated/missing entries, and it is a natural practice to clean the data
The study of their finite substructures leads to a better understanding of the partial order as a whole.
+
first before executing the query. However, the same query might return
 +
different answers on different cleaned versions of the dataset. It is then
 +
helpful to compute the consistent answers: the query answers that will always
 +
be returned, regardless of how the dirty data is cleaned. In this talk, we
 +
first introduce the connection between first-order logic and query languages
 +
on databases, and then discuss the problem of Consistent Query Answering
 +
(CQA): How to compute consistent answers on dirty data? Finally, we show
 +
when the CQA problem can be solved using first-order logic for path queries.
  
=== March 30 4PM - Alice Vidrine ===
+
=== October 12 - Karthik Ravishankar ===
  
Title: Categorical logic for realizability, part I: Categories and the Yoneda Lemma
+
Title: Notions of randomness for subsets of the Natural Numbers
  
Abstract: An interesting strand of modern research on realizability--a semantics for non-classical logic based on a notion of computation--uses the language of toposes and Grothendieck fibrations to study mathematical universes whose internal notion of truth is similarly structured by computation. The purpose of this talk is to establish the basic notions of category theory required to understand the tools of categorical logic developed in the sequel, with the end goal of understanding the realizability toposes developed by Hyland, Johnstone, and Pitts. The talk will cover the definitions of category, functor, natural transformation, adjunctions, and limits/colimits, with a heavy emphasis on the ubiquitous notion of representability.
+
Abstract: There are a number of notions of randomness of sets of natural numbers. These notions have been defined based on what a 'random object' should behave like such as being 'incompressible' or being 'hard to predict' etc. There is often a interplay between computability and randomness aspects of subsets of natural numbers. In this talk we motivate and present a few different notions of randomness and compare their relative strength.
  
==Previous Years==
+
=== October 26 - no seminar ===
 +
 
 +
=== November 9 - Antonio Nákid Cordero ===
 +
 
 +
=== November 23 - Antonio Nákid Cordero? ===
 +
 
 +
=== December 7 - John Spoerl ===
 +
 
 +
== 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 19:55, 24 October 2021

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: Tuesdays 4-5 PM
  • Where: Van Vleck 901
  • Organizers: Jun Le Goh

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

Sign up for the graduate logic seminar mailing list: join-grad-logic-sem@lists.wisc.edu

Fall 2021 tentative schedule

To see what's happening in the Logic qual preparation sessions click here.

September 14 - organizational meeting

We met to discuss the schedule.

September 28 - Ouyang Xiating

Title: First-order logic, database and consistent query answering

Abstract: Databases are a crucial component of many (if not all) modern applications. In reality, the data stored are often dirty and contain duplicated/missing entries, and it is a natural practice to clean the data first before executing the query. However, the same query might return different answers on different cleaned versions of the dataset. It is then helpful to compute the consistent answers: the query answers that will always be returned, regardless of how the dirty data is cleaned. In this talk, we first introduce the connection between first-order logic and query languages on databases, and then discuss the problem of Consistent Query Answering (CQA): How to compute consistent answers on dirty data? Finally, we show when the CQA problem can be solved using first-order logic for path queries.

October 12 - Karthik Ravishankar

Title: Notions of randomness for subsets of the Natural Numbers

Abstract: There are a number of notions of randomness of sets of natural numbers. These notions have been defined based on what a 'random object' should behave like such as being 'incompressible' or being 'hard to predict' etc. There is often a interplay between computability and randomness aspects of subsets of natural numbers. In this talk we motivate and present a few different notions of randomness and compare their relative strength.

October 26 - no seminar

November 9 - Antonio Nákid Cordero

November 23 - Antonio Nákid Cordero?

December 7 - John Spoerl

Previous Years

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