G-Bundles on curves with a twist

Zuvor findet vor dem Uhrturmhörsaal um 16.45 Uhr ein get-together statt.

Prof. Dr. Michael Rapoport, Universität Bonn

In a Bourbaki talk in the 50's, Grothendieck showed that a
G-bundle on a complex curve can be described by an equivariant G-bundle
on a Galois cover of the curve. He pointed out that not every
equivariant G-bundle is obtained in this way if there are ramification
points, and posed the problem of describing equivariant G-bundles in
terms of objects on the base curve. In the talk I will show that the
theory of Bruhat-Tits group schemes allows one to give a satisfactory
answer to this problem. Joint work with G. Pappas.