Speaker: Adam Piggott (Tufts)
Title: Relative train track representatives of free-group automorphisms
Abstract: When thinking about free-group automorphisms, cancellation arguments can be difficult and unsightly. One would like to avoid them by applying geometric intuition whenever possible. The machinery of relative train track representatives, developed in the 1990s by Bestvina, Feighn and Handel, allows one to approach the study of free-group automorphisms by considering homotopy equivalences of finite graphs. I will give an introduction to this powerful piece of machinery, and illustrate the ideas with an application to the study of the growth functions of free-group automorphisms.