Spectral radius, numerical radius, and the product of operators

Rahim Alizadeh, Mohammad B. Asadi, Che-Man Cheng +2

Let $\sigma (A)$, $\rho (A)$ and $r(A)$ denote the spectrum, spectral radius and numerical radius of a bounded linear operator $A$ on a Hilbert space $H$, respectively. We show that a linear…