Automorphisms of simple Chevalley groups over \(Q\)-algebras (Q1893803)

Let \(R\) be a commutative \(\mathbf Q\)-algebra without zero divisors. Suppose \(G(R)\) is a simple Chevalley group of adjoint type, and the rank of \(G\) is greater than 1. Let \(H\) be a subgroup of \(G(R)\) containing the elementary group \(E(R)\). The author proves that all the automorphisms of \(H\) are of the ``standard form''. This leads to the result that \(G(R)\) and \(E(R)\) have isomorphic automorphism groups.