Séminaire de Mathématique

Real Galois cohomology of semisimple groups

by Prof. Mikhail BOROVOI (Tel Aviv University & IHES)

Amphithéâtre Léon Motchane (IHES)

Amphithéâtre Léon Motchane


Le Bois Marie 35, route de Chartres 91440 Bures-sur-Yvette
In a 2-page note of 1969, Victor Kac described automorphisms of finite order of simple Lie algebras over the field of complex numbers C. He used certain diagrams that were later called Kac diagrams. In this talk I will explain the method of Kac diagrams for calculating the Galois cohomology set H^1(R,G) for a connected semisimple algebraic group G (not necessarily simply connected or adjoint) over the field of real numbers R. I will use real forms of the half-spinor group of type D_{2n} as examples. This is a joint work with Dmitry A. Timashev.