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 + 1 over a 2-torsion free commutative ring R with i-dentity.In this paper,we find an automorphism,which is fixed by all orthogonal idempotents and is not an R-algebra automorphism,of T_(n+1)(R).Furthermore we prove that this automorphism is an involutive Jordan automorphism of T_(n+1)( R).