Christoph Schweigert
Viernes 15 de Marzo, 16hs. Aula 13.
We explain how to «count» the number of G-covers on a compact manifold, where G is a finite group. This yields in particular a simple invariant of three-manifolds. We show how to extract from this invariant (and its associated three-dimensional topological field theory) many important notions of modern algebra, in particular the Drinfeld double of the group and module categories over the group ring of G.