
arXiv: 2111.14222
Let $\mathbb{B}(\mathcal{H})$ be the algebra of all bounded linear operators on a Hilbert space $\mathcal{H}$ and let $N(\cdot)$ be a norm on $\mathbb{B}(\mathcal{H})$. For every $0\leq ��\leq 1$, we introduce the $w_{_{(N,��)}}(A)$ as an extension of the classical numerical radius by \begin{align*} w_{_{(N,��)}}(A):= \displaystyle{\sup_{��\in \mathbb{R}}} N\left(��e^{i��}A + (1-��)e^{-i��}A^*\right) \end{align*} and investigate basic properties of this notion and prove inequalities involving it. In particular, when $N(\cdot)$ is the Hilbert--Schmidt norm ${\|\!\cdot\!\|}_{2}$, we present several the weighted Hilbert--Schmidt numerical radius inequalities for operator matrices. Furthermore, we give a refinement of the triangle inequality for the Hilbert--Schmidt norm as follows: \begin{align*} {\|A+B\|}_{2} \leq \sqrt{2w_{_{({\|\!\cdot\!\|}_{2},��)}}^2\left(\begin{bmatrix} 0 & A \\ B^* & 0 \end{bmatrix}\right) - (1-2��)^2{\|A-B\|}_{2}^2} \leq {\|A\|}_{2} + {\|B\|}_{2}. \end{align*} Our results extend some theorems due to F.~Kittaneh et al. (2019).
Linear operators belonging to operator ideals (nuclear, \(p\)-summing, in the Schatten-von Neumann classes, etc.), inequality, Mathematics - Operator Algebras, Norms (inequalities, more than one norm, etc.) of linear operators, Hilbert-Schmidt norm, operator matrix, Functional Analysis (math.FA), weighted numerical radius, Mathematics - Functional Analysis, 47A12, 47A30, 47A63, 47B10, operator norm, Numerical range, numerical radius, FOS: Mathematics, Linear operator inequalities, Operator Algebras (math.OA), numerical radius
Linear operators belonging to operator ideals (nuclear, \(p\)-summing, in the Schatten-von Neumann classes, etc.), inequality, Mathematics - Operator Algebras, Norms (inequalities, more than one norm, etc.) of linear operators, Hilbert-Schmidt norm, operator matrix, Functional Analysis (math.FA), weighted numerical radius, Mathematics - Functional Analysis, 47A12, 47A30, 47A63, 47B10, operator norm, Numerical range, numerical radius, FOS: Mathematics, Linear operator inequalities, Operator Algebras (math.OA), numerical radius
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