Some linear preserver problems on block triangular matrix algebras

WAI-LEONG CHOOI AND MING-HUAT LIM

Research Report No. 2/2002

Abstract

In this article we classify rank-one nonincreasing maps $\psi$ on $n$-square block triangular matrix algebras with the assumption that $\psi (I_n)$ is of rank $n$. As applications, we obtain complete classifications of adjugate-commuting maps, and compound-commuting maps on block triangular matrix algebras.