Automorphisms of Chevalley groups of types A l , D l , E l over local rings without 1/2

Abstract

In this paper, we prove that every automorphism of a Chevalley group of type A l , D l , or E l , l ≥ 3, over a commutative local ring without 1/2 is standard, i.e., it is a composition of ring, inner, central, and graph automorphisms.