Contact Information
Phone: (615) 322-6672
Fax: (615) 343-0215

# Math Calendar

### Upcoming Events

September 2, 2015 (Wednesday), 2:30 pm

Location: Stevenson 1425

September 2, 2015 (Wednesday), 4:10 pm

## Subnormal subgroups in free groups, their growth and co-growth

Alexander Olshanskii, Vanderbilt University
Location: Stevenson 1310

We (1) compare subnormal closures of finite sets in a free group $F$; (2) obtain the limit for the series of subnormal closures of a single element in $F$; (3) prove that the exponential growth rate (e.g.r.) $\lim_{n\to \infty}\sqrt[n]{g_H(n)}$, where $g_H(n)$ is the growth function of a subgroup $H$ with respect to a finite free basis of $F$, exists for any subgroup $H$ of the free group $F$; (4) give sharp estimates from below for the e.g.r. of subnormal subgroups in free groups; and (5) find the co-growth of the subnormal closures of free generators.

September 3, 2015 (Thursday), 4:10 pm

## Departmental Welcome Event

Location: Stevenson 5211

Department Chair Dietmar Bisch will introduce newcomers to the department. Refreshments will follow in Stevenson 1425.

September 9, 2015 (Wednesday), 4:10 pm

## Connes’ character rigidity conjecture for lattices in higher rank groups

Jesse Peterson, Vanderbilt University
Location: Stevenson 1310

We show that lattices in higher rank center-free simple Lie groups are operator algebraic superrigid, i.e., any unitary representation of the lattice which generates a II_1 factor extends to a representation of its group von Neumann algebra. This generalizes results of Margulis and Stuck-Zimmer, and answers in the affirmative a conjecture of Connes.

September 11, 2015 (Friday), 4:10 pm

## Talk Title TBA

Location: Stevenson 1432

September 23, 2015 (Wednesday), 4:10 pm

## Formal conjugacy growth and hyperbolicity

Yago Antolin Pichel, Vanderbilt University
Location: Stevenson 1310

Rivin conjectured that the formal conjugacy growth series of an hyperbolic group is rational if and only if the group is virtually cyclic. In this talk, I will present a proof of Rivin’s conjecture and supporting evidence for the analogous statement for acylindrically hyperbolic groups. This is a joint work with Laura Ciobanu.

September 30, 2015 (Wednesday), 4:10 pm

## Talk Title TBA

Boris Lishak, Toronto
Location: Stevenson 1310

November 13, 2015 (Friday), 4:10 pm

## Talk Title TBA

Matthew Kennedy, University of Waterloo
Location: Stevenson 1432

November 20, 2015 (Friday), 4:10 pm

## Talk Title TBA

Rolando de Santiago, University of Iowa
Location: Stevenson 1432

December 4, 2015 (Friday), 4:10 pm

## Talk Title TBA

Daniel Hoff, UC San Diego
Location: Stevenson 1432