Algebra/Topology Seminar

Speaker: Simona Veselá

Title: The 1.5-type and stable classification of surfaces in 4-manifolds.
 
Abstract: The 1.5-type is a structure on a normal bundle of a manifold in between that of the normal 1- and 2-types of modified surgery.  In a special case it was first used by Hambleton and Kreck in 1993. In an ongoing project I introduce the general theory of 1.5-types and explain their application to external stable classification of surfaces in simply connected 4-manifolds with examples.