On the reduction of powers of self-adjoint operators

Abstract

Let $T\in B(H)$ be such that $T^n$ is self-adjoint for some $n\in \mathbb{N}$ with $n\ge 3$. The paper's primary aim is to establish the conditions that lead to the self-adjointness of $T$. We pay particular attention to the case where $T^3=0$ and how it implies $T$ is complex symmetric.