# Events for 05/13/2020 from all calendars

## Groups and Dynamics Seminar

**Time: ** 12:00PM - 1:00PM

**Location: ** 940 9667 3668

**Speaker: **Joshua Frisch, Caltech

**Title: ***The Poisson Boundary and the ICC property*

**Abstract: **The Poisson Boundary of a random walk on a group is a space which describes the set of possible tail behaviors of the random walk. It has long been known that abelian and nilpotent groups always have trivial Poisson Boundary (groups with this property are called Choquet Deny) and that non-amenable groups never have trivial Poisson Boundary. In this talk I will define the Poisson Boundary, discuss some of these results and prove a new one, classifying exactly which groups are Choquet Deny. This is joint work with Yair Hartman, Omer Tamuz, and Pooya Vahidi Ferdowsi.
ZOOM ID: 940 9667 3668

## Noncommutative Geometry Seminar

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

**Location: ** Zoom 942810031

**Speaker: **Robin Deeley, University of Colorado, Boulder

**Title: ***The K-theory of the stable algebra and stable Ruelle algebra of a Wieler solenoid*

**Abstract: **Wieler has shown that every irreducible Smale space with totally disconnected stable sets is a solenoid (i.e., obtained via a stationary inverse limit construction). Through examples I will discuss how this allows one to compute the K-theory of the stable algebra, S, and the stable Ruelle algebra, S\rtimes Z. These computations involve writing S as a stationary inductive limit and S\rtimes Z as a Cuntz-Pimsner algebra. These constructions reemphasize the view point that Smale space C*-algebras are higher dimensional generalizations of Cuntz-Krieger algebras. As I mentioned the talk will be example based and hence no knowledge of Smale spaces or Wieler solenoids is required. The main results are joint work with Magnus Goffeng and Allan Yashinski.

**URL: ***Event link*