Title:  Compressing surface diffeomorphisms via bordered Floer homology

Speaker:  Akram Alishahi

Abstract:  Let F be a closed surface, and \psi be a diffeomorphism of F. An interesting question with nice topological implications for detecting homotopy ribbon fibered knots is whether \psi extends over some handlebody with boundary F. In 1985, Casson-Long gave an algorithm for answering this question. In this talk, first we will discuss how bordered Floer homology can be used to detect whether \psi extends over a specific handlebody. Then, we will outline how to adapt ideas of Casson-Long to give an algorithm using bordered Floer homology to detect whether \psi extends over any compression body. This is a joint work with Robert Lipshitz.