Spectral properties and tensor products of quasi-*-A(n) operators

Abstract

In this paper, we prove that the spectrum is continuous on the class of all quasi-*-A(n) operators. And we obtain a sufficient condition for a quasi-*-A(n) operator to be normal. Finally, we consider the tensor products of quasi-*-A(n) operators, giving a necessary and sufficient condition for T S to be a quasi-*-A(n) operator when T and S are both non-zero operators.