Smoothing 4-manifolds and homeomorphisms

As a companion to Freedman's lectures I will describe applications of the disk theorem to finding smooth structures on topological 4-manifolds, isotopy of homeomorphisms to be diffeomorphisms on various types of open sets, etc. One consequence is that handlebody structures are equivalent to smooth structures, so generally don't exist. I describe modifications of standard handlebody arguments to work around this problem.