Kangjian Wu

collaborators

3 papers

math.FA2026

Norm attainment of a class of block operator matrices

Kangjian Wu, Jiayu Ling, Qingxiang Xu

Given complex numbers $a, b, c$ and a non-negative continuous function $I ¨ $ defined on $[0, + \infty)$ , consider the $2 \times 2$ matrix $$ M_t = \begin{pmatrix} a & t \\ ct & bÏ(t…

math.FA2025

The numerical ranges of the generalized quadratic operators

Kangjian Wu, Qingxiang Xu

We investigate the generalized quadratic operator defined by $T = (a I_{H} c A^{*} A b I_{K}),$ where $H$ and $K$ are Hilbert spaces, $…

math.FA2025

Convex inequalities in Hilbert $C^{*}$ -modules

Kangjian Wu, Jia Li, Qingxiang Xu

The H $o ¨$ lder-McCarty inequalities are originally derived in the Hilbert space case and have been generalized via a convex inequality. The main purpose of this paper is t…

Norm attainment of a class of block operator matrices

The numerical ranges of the generalized quadratic operators

Convex inequalities in Hilbert C∗-modules

Convex inequalities in Hilbert $C^{*}$ -modules