Contraction par Frobenius de G-modules

Abstract

Let G be a simply connected semisimple algebraic group over an algebraically closed field k of positive characteristic. We will untwist the structure of G-modules by a newly found splitting of the Frobenius endomorphism on the algebra of distributions of G, which, for example, explains the subsumed G-equivariant nature of the Frobenius splitting of the flag variety of G.