Some refinements of numerical radius inequalities

Zahra Heydarbeygi, Maryam Amyari, Mahnaz Khanehgir

In this paper, we give some refinements for the second inequality in $\frac{1}{2}\Vert A\Vert \le w(A)\le \Vert A\Vert$, where $A\in B(H)$. In particular, if $A$ is hyponormal by refining the…