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# Events for 09/11/2019 from all calendars

## Student Working Seminar in Groups and Dynamics

## Numerical Analysis Seminar

## Groups and Dynamics Seminar

## Committee P&T Meeting

## Graduate Student Organization Seminar

## Committee P Meeting

## First Year Graduate Student Seminar

## AMUSE

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

**Location:** BLOC 628

**Speaker:** Krzysztof Święcicki

**Title:** *A Brief Introduction to 3 Dimensional Manifolds*

**Abstract:** In his celebrated work from 2003, Perelman finished the proof of Poincare conjecture in dimension 3. His result is in fact far stronger and implies Thurston's geometrization conjecture, which classifies possible geometric structures on 3 manifolds. I'll give an overview of the result and introduce all eight basic geometries and their connection to group theory. I won't assume any knowledge outside of basic topology, so any newcomers are welcome.

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

**Location:** BLOC 628

**Speaker:** Winnifried Wollner, TU Darmstadt

**Title:** *Optimization of Phase-Field Damage Evolution*

**Abstract:** Within this talk, we will address optimization problems governed by time-discrete phase-field damage processes. The presence of an irreversibility of the fracture growth gives rise to a nonsmooth system of equations. To derive optimality conditions we introduce an additional regularization and show that the resulting optimization problem is well-posed. To tackle discretization errors, as well as convergence in the limit of the irreversibility penalty, an improved differentiability result is shown for the time discrete regularized damage process. Based upon this, we can show that certain local minimizers of the optimization problem can be approximated by the proposed penalty approach. Further, we will give a short discussion of resulting discretization error estimates.

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

**Location:** BLOC 220

**Speaker:** Nguyen-Bac Dang, Stonybrook

**Title:** *Spectral gap in the dynamical degrees of tame automorphism preserving an affine quadric threefold*

**Abstract:** In this talk, I will present the tame automorphisms group preserving an affine quadric threefold. The main focus of my talk is the understanding of the degree sequences induced by the elements of this group. Precisely, I will explain how one can apply some ideas from geometric group theory in combination with valuative techniques to show that the values of the dynamical degrees of these tame automorphisms admit a spectral gap. Finally I will apply these techniques to study random walks on this particular group.

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

**Location:** BLOC 220

**Speaker:** Committee P&T Meeting, Texas A&M University

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

**Location:** BLOC 628

**Speaker:** Konrad Wrobel

**Title:** *Random Rooted Graphs*

**Abstract:** Random rooted graphs are connected to many different areas of mathematics, including percolation theory, sofic groups, locally compact groups, and ergodic theory. They arise naturally when one attempts to define a notion of convergence for sequences of finite graphs. We'll introduce Benjamini-Schramm convergence and discuss some open problems and applications related to it. We'll then switch gears and discuss the Mass Transport Principal and unimodular graphs. If time permits, I will mention some applications to percolation theory.

**Time:** 4:30PM - 5:30PM

**Location:** BLOC 220

**Speaker:** Committee P Meeting, Texas A&M University

**Time:** 5:30PM - 6:30PM

**Location:** Blocker 628

**Title:** *Outreach Opportunities*

**Time:** 6:00PM - 7:00PM

**Location:** Blocker 2F

**Title:** *Math Undergraduate Research Expo*

**Abstract:** A number of math students will present posters describing their research and results, and will be on hand to talk about their experience. As usual, pizza and drinks will be available.

**URL:** *Link*

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