Mapping class groups of infinite-type surfaces and their actions on hyperbolic graphs
Given a finite-type surface, there are two important objects naturally associated to it. The first is the mapping class group and the second is the curve graph, which the mapping class group acts on via isometries. This action is well understood and has been extremely useful in understanding the algebraic and geometric properties of mapping class groups. For instance, the elements acting loxodromically on the curve graph and precisely the pseudo-Anosov homeomorphisms. In this talk I’ll discuss recent joint work with Carolyn Abbott and Nicholas Miller as well as a project with Sam Taylor regarding infinite-type mapping classes that act as loxodromic isometries on graphs associated to infinite-type surfaces. The aim of these projects is to work towards a Nielsen-Thurston type classification of mapping classes for infinite-type surfaces and to understand which homeomorphisms are the generalizations of pseudo-Anosovs is in this setting.