Powers of posinormal operators

Abstract

Square of a posinormal operator is not necessarily posinormal$.$ But (i) powers of quasiposinormal operators are quasiposinormal and, under closed ranges assumption, powers of (ii) posinormal operators are posinormal, (iii) of operators that are both posinormal and coposinormal are posinormal and coposinormal, and (iv) of semi-Fredholm posinormal operators are posinormal.

Cited by in corpus (2)

• A conjecture on hyponormality for the Cesàro matrix of positive integer order
• The generalized Cesàro matrices of order three are supraposinormal on ${\ell }^2$