Topologically isotopic and smoothly inequivalent 2-spheres in simply connected 4-manifolds whose complement has a prescribed fundamental group

Abstract

We describe a procedure to construct infinite sets of pairwise smoothly inequivalent 2-spheres in simply connected 4-manifolds, which are topologically isotopic and whose complement has a prescribed fundamental group that satisfies some conditions. This class of groups include finite cyclic groups and the binary icosahedral group. These are the first known examples of knotting phenomena in 4-manifolds with such properties. Examples of locally flat embedded 2-spheres in non-smoothable 4-manifolds are also given.