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# Events for 12/04/2019 from all calendars

## Student Working Seminar in Groups and Dynamics

## Number Theory Seminar

## Noncommutative Geometry Seminar

## Linear Analysis Seminar

## Working Seminar in Orbit Equivalence and Measured Group Theory

**Time:** 1:00PM - 2:00PM

**Location:** BLOC 628

**Speaker:** James O'Quinn

**Title:** *The Furstenberg-Zimmer structure theorem and a proof of Szemerédi's theorem*

**Abstract:** The Furstenberg-Zimmer structure theorem is a way to partially recover the dichotomy between weak mixing and compact vectors inherent in the study of unitary representations of groups into the p.m.p. action setting. During this talk, I will prove one version of the Furstenberg-Zimmer theorem using some measure theoretic techniques, and then show how Szemerédi's theorem follows from this result.

**Time:** 1:45PM - 2:45PM

**Location:** BLOC 220

**Speaker:** Guchao Zeng, Texas A&M University at Qatar

**Title:** *Modular Equations and Traces of Singular Moduli over Function Fields*

**Abstract:** In this talk, I will introduce the modular polynomials as well as the relation between j-invariants and class polynomials in classical number fields. And then I will give the corresponding theorem in function fields and derive the equation giving value to the trace of the class polynomial, which is a summation of a few j-invariants. This work is joint with A. El-Guindy, R. Masri and M. Papanikolas.

**Time:** 2:00PM - 3:00PM

**Location:** BLOC 628

**Speaker:** Mizanur Rahaman, Institute for Quantum Computing / University of Waterloo

**Title:** *Bisynchronous Games and Factorizable Maps*

**Abstract:** In the theory of non-local games, the graph isomorphism game stands out to be an intriguing one. Specially when the algebra of this game is considered. This is because this game establishes a close connection between the algebra of the game and the theory of quantum permutation groups. It turns out that the graph isomorphism game is an example of a bisynchronous game. In this talk, I will introduce these games and the corresponding correlations arising from the perfect strategies for such games. Moreover, when the number of inputs is equal to the number of outputs, each bisynchronous correlation gives rise to a completely positive map which will be shown to be factorizable in the sense of Haagerup-Musat. This is a joint work with Vern Paulsen.

**Time:** 2:00PM - 3:00PM

**Location:** BLOC 628

**Speaker:** Miza Rahaman, University of Waterlooo

**Title:** *Bisynchronous Games and Factorizable Maps*

**Abstract:** In the theory of non-local games, the graph isomorphism game stands out to be an intriguing one. Specially when the algebra of this game is considered. This is because this game establishes a close connection between the algebra of the game and the theory of quantum permutation groups. It turns out that the graph isomorphism game is an example of a bisynchronous game. In this talk, I will introduce these games and the corresponding correlations arising from the perfect strategies for such games. Moreover, when the number of inputs is equal to the number of outputs, each bisynchronous correlation gives rise to a completely positive map which will be shown to be factorizable in the sense of Haagerup- Musat. This is a joint work with Vern Paulsen.

**Time:** 3:00PM - 4:00PM

**Location:** BLOC 605AX

**Speaker:** Konrad Wrobel

**Title:** *Integrable Orbit Equivalence Rigidity for Free Groups*

**Abstract:** We will discuss a result of Lewis Bowen that shows if an accessible group is $L^1$-orbit equivalent to a free group, then it is virtually free.

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