Max Dehn Seminar

on Geometry, Topology, Dynamics, and Groups

Spring 2013

Date Speaker Title — click for abstract (if available)
February 20 Ken Bromberg
University of Utah
Stable commutator length on mapping class groups
We will discuss stable commutator length on mapping class groups.
February 27 Laura DeMarco
University of Illinois, Chicago
Degenerations of complex dynamical systems
Given a family of rational maps or polynomials, a basic problem is to understand what happens (dynamically) as the family degenerates. In this talk, I will describe a limiting object as a "non-archimedean dynamical system" in terms of a rational function acting on a Berkovich space. In geometric terms, this is a dynamical system on an R-tree.
March 27 Kevin Wortman
University of Utah
April 3 Sam Taylor
University of Texas
Convex cocompactness in Mod(S) via quasiconvexity in RAAGs
We will characterize convex cocompact subgroups of mapping class groups that arise as subgroups of specially embedded right-angled Artin groups. With this characterization, we construct convex cocompact subgroups of Mod(S) with "small translation length" on the curve complex. This is joint work with Johanna Mangahas.
April 24 Daniel Studenmund
University of Chicago
Abstract commensurators of lattices in Lie groups
The abstract commensurator of a group G is the group of all isomorphisms between finite index subgroups of G up to a natural equivalence relation. Commensurators of lattices in semisimple Lie groups are well understood, using strong rigidity results of Mostow, Prasad, and Margulis. We will describe commensurators of lattices in solvable groups, where strong rigidity fails. If time permits, we will extend these results to lattices in certain groups that are neither solvable nor semisimple.

Current seminar          Archive of past talks
Max Dehn Seminar is organized by Mladen Bestvina, Ken Bromberg, Patrick Reynolds,
Jing Tao, Domingo Toledo, and Kevin Wortman.

This web page is maintained by Patrick Reynolds and Jing Tao.