New upper bounds for the q-numerical radii of 2×2 operator matrices

IF 2.1 2区数学 Q1 MATHEMATICS, APPLIED

Journal of Computational and Applied Mathematics Pub Date : 2025-03-06 DOI:10.1016/j.cam.2025.116618

Fuad Kittaneh , M.H.M. Rashid

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引用次数: 0

Abstract

This article introduces several enhanced bounds for the

q

-numerical radius concerning the sum and product of bounded linear operators in complex Hilbert spaces. Our findings represent a significant advancement over existing bounds in the current literature. Notably, the

q

-numerical radius inequalities for operator products and commutators are particular cases of our broader results. Furthermore, we derive new inequalities specifically targeting the

q

-numerical radii of

2 \times 2

operator matrices. These contributions not only refine the understanding of

q

-numerical radius bounds but also extend their applicability in operator theory. Through these improvements, we provide a more comprehensive framework that can be utilized to analyze and estimate the numerical radius in various contexts involving bounded linear operators.

查看原文本刊更多论文

2×2算子矩阵的q数值半径的新上界

本文介绍了复Hilbert空间中有界线性算子的和与积的q数值半径的几个增强界。我们的研究结果在现有文献的基础上取得了重大进展。值得注意的是，算子积和换向子的q数值半径不等式是我们更广泛的结果的特殊情况。进一步，我们推导了新的不等式，特别是针对2×2算子矩阵的q数值半径。这些贡献不仅完善了对q数值半径界的理解，而且扩展了它们在算子理论中的适用性。通过这些改进，我们提供了一个更全面的框架，可用于分析和估计涉及有界线性算子的各种情况下的数值半径。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Computational and Applied Mathematics 数学-应用数学

CiteScore

5.40

自引率

4.20%

发文量

437

审稿时长

3.0 months

期刊介绍： The Journal of Computational and Applied Mathematics publishes original papers of high scientific value in all areas of computational and applied mathematics. The main interest of the Journal is in papers that describe and analyze new computational techniques for solving scientific or engineering problems. Also the improved analysis, including the effectiveness and applicability, of existing methods and algorithms is of importance. The computational efficiency (e.g. the convergence, stability, accuracy, ...) should be proved and illustrated by nontrivial numerical examples. Papers describing only variants of existing methods, without adding significant new computational properties are not of interest. The audience consists of: applied mathematicians, numerical analysts, computational scientists and engineers.