Tightening Bounds on the Numerical Radius for Hilbert Space Operators

Maryam Jalili, Hamid Reza Moradi

Let $S$ be a bounded linear operator on a Hilbert space. We show that if $S$ is accretive (resp. dissipative the sense that $\frac{S-S^{\ast }}{2i}$ is positive) in the sense that…