Geometry and Topology Seminar - "Coverings, groupoids, and embedding braids in mapping class groups ", Tyrone Ghaswala
University of Waterloo
Title: Coverings, groupoids, and embedding braids in mapping class groups.
Abstract: Given a finite-sheeted branched cover between surfaces with boundary, it is natural to ask whether every mapping class of the covering surface projects to the base surface, and whether every mapping class of the base surface lifts to the covering surface. In this talk we will address these questions, with automorphisms of fundamental groupoids playing an integral role. As a consequence of the main result, we construct new embeddings of the braid group in the mapping class group of a surface. This is joint work with Alan McLeay.