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# Events for 10/16/2019 from all calendars

## Student Working Seminar in Groups and Dynamics

## Noncommutative Geometry Seminar

## Groups and Dynamics Seminar

## Graduate Student Organization Seminar

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

**Location:** BLOC 628

**Speaker:** Amanda Hoisington

**Title:** *Coarse embeddings under group extensions*

**Abstract:** I will be going over a paper by Arzhantseva and Tessera (2017) which proves, by construction, that admitting a coarse embedding into Hilbert space is not preserved under group extension.

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

**Location:** BLOC 628

**Speaker:** Jianchao Wu, Texas A&M University

**Title:** *The K-theory of C*-algebras associated to certain infinite dimensional spaces*

**Abstract:** Noncommutative geometry provides a potent approach to the study of the algebraic geometry (e.g., K-theory) of infinite dimensional manifolds. In this talk, I will outline the construction of C*-algebras associated to Hilbert-Hadamard spaces, understood as a kind of (typically infinite dimensional) nonpositively curved manifolds. Under mild assumptions, these C*-algebras retain a remnant of Bott periodicity, which we exploit to prove the Novikov conjecture of geometrically discrete groups of diffeomorphisms. This is joint work with Sherry Gong and Guoliang Yu.

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

**Location:** BLOC 220

**Speaker:** Vadim Kaimanovich, University of Ottawa

**Title:** *Freedom and boundaries*

**Abstract:** I will outline recent results (joint with Anna Erschler) on the stabilizers of the group action on its Poisson boundary: existence of a free boundary action for any group with infinite conjugacy classes, a complete description of the possible kernels of such actions, and an example of a totally non-free boundary action.

**Time:** 4:00PM - 5:00PM

**Location:** BLOC 628

**Speaker:** Tolulope Oke

**Title:** *Cup Products on Hochschild Cohomology*

**Abstract:** The Hochschild cohomology of an associative algebra $\Lambda$ possesses a cup product making it a graded commutative ring. I will give equivalent definitions of the cup product on Hochschild cohomology. There is a cup product formula on the Hochschild cohomology of a family of quiver algebras. I will present this formula and if time permits, I will discuss its application in connection to a finite generation conjecture.

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