Events for 10/23/2020 from all calendars

Working Seminar in Orbit Equivalence and Measured Group Theory

Time: 11:00AM - 12:00PM

Location: Zoom

Speaker: Konrad Wrobel

Title: An introduction to arithmetic groups and some facts about semisimple Lie groups

Abstract: The goal of this seminar is to study arithmetic subgroups of semisimple Lie groups. By definition, the subject combines algebra(groups of matrices) with number theory(groups of integers). There are also many important connections to geometry(fundamental groups of locally symmetric spaces) and various properties that geometric group theorists find interesting. The tools used come from several of these fields, but surprisingly enough, many of the tools come from ergodic theory. Some of the ultimate goals of the seminar include Margulis Superrigidity, Mostow Rigidity, and the classification of arithmetic subgroups of classical groups. This first lecture will give an outline of the goals and tools involved and start giving several definitions as well as discuss some basics about Lie groups. We will be reading from Dave Witte Morris's "An Introduction to Arithmetic Groups." Please contact Konrad Wrobel for the zoom link.

Spectral Theory Reading Seminar

Time: 11:00AM - 11:50AM

Location: Zoom

Speaker: Wencai Liu, Texas A&M University

Title: Several approaches to calculate the spectrum of the free discrete Schrodinger operator II

Mathematical Physics and Harmonic Analysis Seminar

Time: 1:50PM - 2:50PM

Location: Zoom

Speaker: Jun Kitagawa, Michigan State University

Title: On free discontinuities in optimal transport

Abstract: It is well known that regularity results for the optimal transport (Monge-Kantorovich) problem require rigid geometric restrictions. In this talk, we consider the structure of the set of ``free discontinuities'' which arise when transporting mass from a connected domain to a disconnected one, and show regularity of this set, along with a stability result under suitable perturbations of the target measure. These are based on a non-smooth implicit function theorem for convex functions, which is of independent interest. This talk is based on joint work with Robert McCann (Univ. of Toronto).

Algebra and Combinatorics Seminar

Time: 3:00PM - 4:00PM

Location: Zoom

Speaker: Kassie Archer, UT Tyler

Title: Cycle structure of pattern-avoiding permutations

Abstract: Given a permutation written in its one-line notation, we say that the permutation avoids a pattern if there is no subsequence in the same relative order as that pattern. Though much is known about pattern-avoiding permutations in general, relatively little is known about the cycle structure of these permutations. In the first half of the talk, I will discuss some things that are known about this topic, in what context some of these results appear, and some open questions. In the second half, I’ll discuss a recent example regarding 132-avoiding permutations comprised of only 3-cycles which has an interesting answer.

Open Teaching with Technology Forum

Time: 3:30PM - 5:00PM

Location: Zoom

Speaker: Vanessa Coffelt

Description: Join Zoom Meeting: https://tamu.zoom.us/j/93142718312?pwd=c2x5Zm5RZWdheEJ4SU40N3VYMlFpdz09 Meeting ID: 931 4271 8312