New generalized numerical radius inequalities for Hilbert space operators

Abstract

We define generalized real and imaginary parts of an operator, as well as the generalized wh,g(⋅) numerical radius, which reduces to the t-weighted numerical radius for suitable functions h,g. Usual properties regarding the new numerical radius are shown, as well as various inequalities concerning the ratio between wh,g(⋅) and w(⋅). In the last section, we give operator matrix inequalities, which generalize the standard numerical radius inequalities, and in one case it is shown that the inequality obtained is sharper than the inequality given by Ammar et al. (Kyungpook Math. J. 65(1):63–75, 2025, Theorem 2.13) for specific operator matrices.