Department of

Mathematics


Seminar Calendar
for Descriptive Set Theory Seminar events the year of Saturday, February 15, 2020.

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More information on this calendar program is available.
Questions regarding events or the calendar should be directed to Tori Corkery.
     January 2020          February 2020            March 2020     
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           1  2  3  4                      1    1  2  3  4  5  6  7
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Wednesday, January 22, 2020

3:30 pm in 341 Altgeld Hall,Wednesday, January 22, 2020

Organizational meeting

Wednesday, January 29, 2020

3:30 pm in 341 Altgeld Hall,Wednesday, January 29, 2020

Introduction to IRS

Jenna Zomback and Anush Tserunyan

Abstract: This is an introductory talk on Invariant Random Subgroups (IRS), which can be viewed as probabilistic generalization of normal subgroups and lattices. We will show that for all countable groups, all IRS arise from pmp actions, and discuss Kesten's theorem for IRS. All this is from the paper "Kesten's theorem for Invariant Random Subgroups" by Abert, Glasner, and Virag [arXiv].

Wednesday, February 5, 2020

3:30 pm in 341 Altgeld Hall,Wednesday, February 5, 2020

Cancelled

Wednesday, February 12, 2020

3:30 pm in 341 Altgeld Hall,Wednesday, February 12, 2020

Strongly amenable groups

Joshua Frisch (Caltech Math)

Abstract: A topological dynamical system (i.e. a group acting by homeomorphisms on a compact Hausdorff space) is said to be proximal if for any two points $p$ and $q$ we can simultaneously "push them together" (rigorously, there is a net $g_n$ such that $\lim g_n(p) = \lim g_n(q)$). In his paper introducing the concept of proximality, Glasner noted that whenever $\mathbb{Z}$ acts proximally, that action will have a fixed point. He termed groups with this fixed point property "strongly amenable" and showed that non-amenable groups are not strongly amenable and virtually nilpotent groups are strongly amenable. In this talk I will discuss recent work precisely characterizing which (countable) groups are strongly amenable. This is joint work with Omer Tamuz and Pooya Vahidi Ferdowsi.

Wednesday, March 25, 2020

3:30 pm in 341 Altgeld Hall,Wednesday, March 25, 2020

To Be Announced

Aristotelis Panagiotopoulos (Caltech Math)

Wednesday, April 22, 2020

3:30 pm in 341 Altgeld Hall,Wednesday, April 22, 2020

To Be Announced

Anton Bernshteyn (Carnegie Mellon Math)