Motivated by some problems from theoretical physics, we describe a toy model problem of counting isometric immersions of certain graphs in the flat torus. This is joint work with David Aulicino and Harry Richman. There will be lots of pictures, and hopefully, some discussion of the motivations.
Infinite-type surfaces and their isometry groups
A surface is of finite type if it is homeomorphic to a compact surface with at most finitely many points removed. Otherwise, the surface is of infinite-type. There has been a recent surge of interest in infinite-type surfaces and their groups of symmetries, which arise naturally in a variety of contexts. In this talk, I will give a crash course on infinite-type surfaces before discussing joint work with T. Aougab and N. Vlamis in which we characterize the isometry groups of infinite-genus hyperbolic surfaces.
Notes from Priyam's talk are available here.
When is a given map of a surface to a 4-manifold homotopic to an embedding? I’ll motivate this question and give a survey of related results, including the work of Freedman and Quinn, and culminating in a general surface embedding theorem. The talk will be based on joint work with Daniel Kasprowski, Mark Powell, and Peter Teichner.
We will discuss the global topological structure of the space of all closed subgroups of PSL(2,R), endowed with the Chabauty topology.
Notes from Ian's talk are available here.