This page list all events and seminars that take place in the department this week. Please use the form below to choose a different week or date range.

## Geometry and Group Theory

### Property (T) of Groups, Groupoids, and C*-algebras and their relationships

May 21, 14:30-15:30, 2017, -101

#### Speaker

Kyle Austin (Ben-Gurion)

#### Abstract

Bekka has defined a notion of property (T) for C-algebras that is congruous with property (T) groups in the sense that any C-completion of the complex group ring has property (T) if and only if the group does. We will outline the fairly straightforward proof of this fact, as well as discuss some ideas that Joav Orovitz and I have for “generalizing” property (T) for C*-algebras so that the analogous statement is true for groupoids and completions of their convolution algebras.

### The Noriko Sakurai fellowship and the Friedman prize for the year 2017

May 23, 14:00-16:00, 2017, Deichmann building for Mathematics (58), Seminar room -101, BGU

## Probability and ergodic theory (PET)

### Quantitative multiple recurrence for two and three transformations.

May 23, 10:50-12:00, 2017, Math -101

#### Speaker

Sebastián Donoso (University of O'higgins)

#### Abstract

In this talk I will provide some counter-examples for quantitative multiple recurrence problems for systems with more than one transformation. For instance, I will show that there exists an ergodic system $(X,\mathcal{X},\mu,T_1,T_2)$ with two commuting transformations such that for every $% $ there exists $A\in \mathcal{X}$ such that $% $ for every $n \in \mathbb{N}$. The construction of such a system is based on the study of big’’ subsets of $\mathbb{N}^2$ and $\mathbb{N}^3$ satisfying combinatorial properties.

This a joint work with Wenbo Sun.

## Algebraic Geometry and Number Theory

### On convolution of algebraic morphisms and some applications

May 24, 15:10-16:30, 2017, Math -101

#### Speaker

Itay Glazer (Weizmann)