# Math Calendar

### Upcoming Events

## Graduate Student Tea

## Graduate Student Tea

Location: Stevenson 1425

## Topology & Group Theory Seminar

## The Baum-Connes Correspondence for the Pure Braid Group on Four Strands

Lauren Ruth, Vanderbilt University

Location: Stevenson 1308

We calculate the left-hand side and the right-hand side of the Baum-Connes correspondence for the pure braid group on four strands, each side relying on different techniques. This is joint work with Sara Azzali, Sarah Browne, Maria Paula Gomez Aparicio, and Hang Wang.

## Colloquium

## Invariants of Rings via Equivariant Homotopy

Teena Gerhardt, Michigan State University

Location: Stevenson 5211

Algebraic K-theory is an invariant of rings which illustrates a fascinating interplay between algebra and topology. Defined using topological tools, this invariant has important applications to algebraic geometry, number theory, and geometric topology. One fruitful approach to computing algebraic K-theory uses equivariant homotopy theory, a branch of algebraic topology which studies topological objects with a group action. In this talk I will give an introduction to algebraic K-theory and its applications, and talk about modern methods to compute algebraic K-theory.

## PDE Seminar

## Large Time Behavior of the Fractional Porous Medium Equation on Riemannian Manifolds via Fractional Logarithmic Sobolev Inequalities

Yuanzhen Shao, University of Alabama

Location: Stevenson 1307

In 1995, Carlen and Loss proposed a novel approach to study the asymptotics the 2–D Navier–Stokes equation by using a Logarithmic Sobolev inequality. Later, this idea was adopted by Bonforte and Grillo to study the asymptotics of the Porous Medium Equation. In this talk, I will discuss how to derive various Sobolev type inequality involving fractional Laplacian. Then I will use these inequalities to study the smooth effect and asymptotic behavior of the Fractional Porous Medium Equation on complete Riemannian manifolds.

## Subfactor Seminar

## Free Stein Irregularity and Dimension

Brent Nelson, Michigan State University

Location: Stevenson 1432

Given an n-tuple $X$ of non-commutative random variables, its free Stein discrepancy relative to the semicircle law (the non-commutative analogue of classical Stein discrepancy relative to the Gaussian distribution) measures how “close” the distribution of $X$ is to the semicircle law. By considering free Stein discrepancies relative to a broader class of laws, one can define a quantity called the free Stein irregularity. I will discuss this quantity and show how it can be related to other free probabilistic quantities such as the free Fisher information and the non-microstates free entropy dimension. I will also show how it can be easily computed for a number of interesting examples. This is based on joint work with Ian Charlesworth.

## Undergraduate Seminar

## Talk Title TBA

Bogdan Chornomaz, Vanderbilt University

Location: Stevenson 1206

## Topology & Group Theory Seminar

## Hierarchically Hyperbolic Groups: An Introduction

Jason Behrstock, CUNY

Location: Stevenson 1308

Hierarchically hyperbolic spaces provide a uniform framework for working with many important examples, including mapping class groups, right angled Artin groups, Teichmuller space, most cubulated groups, and others. In this talk I’ll provide an introduction to studying groups and spaces from this point of view, both describing new tools to use to study these groups and applications of those results. This talk will include joint work with Mark Hagen and Alessandro Sisto.

## Number Theory Seminar

## Talk Title TBA

Doug Hardin, Vanderbilt University

Location: Stevenson 1320

## Subfactor Seminar

## Talk Title TBA

Bin Gui, Rutgers University

Location: Stevenson 1432

## PDE Seminar

## Talk Title TBA

Theodore Drivas, Princeton University

Location: Stevenson 1307

## Topology & Group Theory Seminar

## Talk Title TBA

Genevieve Walsh, Tufts University

Location: Stevenson 1308

## Topology & Group Theory Seminar

## Talk Title TBA

Talia Fernós, University of North Carolina, Greensboro

Location: Stevenson 1308

## Number Theory Seminar

## Talk Title TBA

John Voight, Dartmouth College

Location: Stevenson 1320

## Topology & Group Theory Seminar

## Talk Title TBA

Michael Ben-Zvi, Tufts University

Location: Stevenson 1308

## PDE Seminar

## Talk Title TBA

Geng Chen, University of Kansas

Location: Stevenson 1307

## Topology & Group Theory Seminar

## Talk Title TBA

Carolyn Abbott, Columbia University

Location: Stevenson 1308

## Number Theory Seminar

## Talk Title TBA

Marie Jameson, University of Tennessee

Location: Stevenson 1320

## Topology & Group Theory Seminar

## Talk Title TBA

Michael Hull, University of North Carolina, Greensboro

Location: Stevenson 1308