An involutive Jordan automorphism of triangular matrix algebra over commutative rings

摘要

Let T n+1(R)be upper matrix algebra of order n+1over a 2-torsion free commutative ring Rwith identity. In this paper, we find an automorphism, which is fixed by all orthogonal idempotents and is not an R-algebraautomorphism, of T n+1(R). Furthermore we prove that this automorphism is an involutive Jordan automorphism of T n+1(R).