Wednesday, 8th of October 2025, 13:00-13:45 in HG03.082.
Julius Groenjes
What is Bordism?
Two smooth, closed n-manifolds N and M are bordant if there is an (n+1)-dimensional compact smooth manifold whose boundary is diffeomorphic to the disjoint union of N and M. This simple and highly intuitive notion has been a part of Algebraic Topology since its inception, and is more relevant today than ever. The topic of this talk is bordism theory, its history from its inception by Poincaré in 1985 and the homotopical underpinnings examined by Lev Pontryagin and René Thom in the 40s and 50s, as well as many examples, calculations, and a few homotopical insights into this fascinating topic.