Seminars & Colloquia Calendar

Abstract:  A venerable technique to study manifolds of dimension n is to consider invariants of submanifolds of dimension n-1, dual to a 1-dimensional cohomology class. A classic instance of this technique in dimension 4 arises from Rochlin’s theorem about smooth spin 4-manifolds. I will describe what 4-dimensional gauge theory (Seiberg-Witten theory and Yang-Mills theory) tells us about such invariants, and give some applications of this new point of view.