On inequalities for A-numerical radius of operators

Pintu Bhunia, Kallol Paul, Raj Kumar Nayak

Published 2019-08-29Version 1

Let $A$ be a positive operator on a complex Hilbert space $\mathbb{H}.$ We present inequalities concerning upper and lower bounds for $A$-numerical radius of operators, which improve on and generalize the existing ones, studied recently in [A. Zamani, A-Numerical radius inequalities for semi-Hilbertian space operators, Linear Algebra Appl. 578 (2019) 159-183]. We also obtain some inequalities for $B$-numerical radius of $2\times 2$ operator matrices where $B$ is the $2\times 2$ diagonal matrix whose diagonal entries are $A$. Further we obtain upper bounds for $A$-numerical radius of product of operators which improve on the existing bounds.