Filippo Baroni, Trinity College Dublin
Event Date
2026-09-16
Event Time
02:30 pm ~ 03:30 pm
Event Location
Wachman 617
Abstract: According to the Nielsen-Thurston classification theorem, elements of the mapping class group of a surface come in three guises: periodic, reducible, and pseudo-Anosov. This talk addresses a very natural question: how can we tell these three classes apart (and, in particular, pseudo-Anosov from the other two)? We will review several strategies, including a recent algorithm that recognises pseudo-Anosov mapping classes in polynomial time. In particular, we will discuss how pseudo-Anosov recognition can be reduced to the computation of distances in the curve graph of a surface, and how work of Masur and Minsky can help us tackle this problem.