String topology and the intersection product

String topology, as introduced by Chas and Sullivan 20 years ago, is a product structure on the free loop space of a manifold that lifts the classical intersection product from the manifold to its loop space. I’ll explain how both a product and a coproduct can be defined by lifting the intersection product, and how this leads to a very rich structure that we still do not fully understand.



University of Copenhagen; Member, School of Mathematics