Title: Teichmuller theory in outer space (joint work with Michael Handel)

Lee Mosher (Rutgers University - Newark)

Tuesday, December 2 at 1:30pm in Malott 406

Abstract:

The outer automorphism group Out(F_n) of a free group of rank n acts on the Culler Vogtmann moduli space of marked, metric graphs of rank n, known as "outer space" X_n. This action is analogous to the action of the mapping class group of a surface on the Teichmuller space of that surface. Using the structure of Teichmuller space as a guide, we are exploring various questions and conjectures about the structure of outer space. This talk will focus on some initial results regarding expansion factors and axes of outer automorphisms Phi which are completely irreducible, meaning that Phi^n is irreducible for all n >= 1.