Stably exotic fillings of 3-manifolds

Stably exotic fillings of a three-manifold are four-manifolds with that boundary which are homeomorphic but remain inequivalent under stable diffeomorphism relative to the boundary. This seminar shows that every closed orientable three-manifold admits such fillings, along with certain families of nonorientable three-manifolds. It contrasts these examples with three-manifolds containing a two-sided real projective plane: any two smooth homeomorphic fillings in that case are stably diffeomorphic. The results are joint work with Patrick Orson, Mark Powell and Arunima Ray.