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Let $D$ and $U$ be linear operators in a vector space (or more generally, elements of an associative algebra with a unit). We establish binomial-type identities for $D$ and $U$ assuming that either their commutator $[D,U]$ or the second…

Classical Analysis and ODEs · Mathematics 2018-01-17 Peter Kuchment , Sergey Lvin

While monotone operator theory is often studied on Hilbert spaces, many interesting problems in machine learning and optimization arise naturally in finite-dimensional vector spaces endowed with non-Euclidean norms, such as…

Optimization and Control · Mathematics 2025-08-26 Alexander Davydov , Saber Jafarpour , Anton V. Proskurnikov , Francesco Bullo

General Hardy-Carleman type inequalities for Dirac operators are proved. New inequalities are derived involving particular traditionally used weight functions. In particular, a version of the Agmon inequality and Treve type inequalities are…

Spectral Theory · Mathematics 2015-10-28 Alexandra Enblom

In this paper, we introduce the concept of operator geometrically convex functions for positive linear operators and prove some Hermite-Hadamard type inequalities for these functions. As applications, we obtain trace inequalities for…

Functional Analysis · Mathematics 2015-08-14 Ali Taghavi , Vahid Darvish , Haji Mohammad Nazari , Sever S. Dragomir

Several new improvements of the $A$-numerical radius inequalities for operators acting on a semi-Hilbert space, i.e., a space generated by a positive operator $A$, are proved. In particular, among other inequalities, we show that…

Functional Analysis · Mathematics 2021-01-05 Kais Feki

The aim of the present paper is, firstly we study the concepts of (m, (q_1, ..., q_d))- partial isometries on a Hilbert space, secondly, we introduce the notion of m- invertibility of tuples of operators as a natural generalization of the…

Functional Analysis · Mathematics 2016-03-01 Ould Ahmed Mahmoud Sid Ahmed

We prove inequalities on symmetric tensor sums of positive definite operators. In particular, we prove multivariable operator inequalities inspired by generalizations to the well-known Hlawka and Popoviciu inequalities. As corollaries, we…

Functional Analysis · Mathematics 2014-11-18 Wolfgang Berndt , Suvrit Sra

We examine the averaging operator $T$ corresponding to the manifold in $\mathbb{R}^{2d}$ of pairs of points $(u,v)$ satisfying $|u| = |v| = |u - v| = 1$, so that $\{0,u,v\}$ is the set of vertices of an equilateral triangle. We establish…

Classical Analysis and ODEs · Mathematics 2023-05-05 Eyvindur A. Palsson , Sean R. Sovine

In this paper, we establish several inequalities of Dirichlet eigenvalues for Laplace operator $\Delta $ with any order on \emph{n}-dimensional Euclidean space. These inequalities are more general than known Yang's inequalities and contain…

Analysis of PDEs · Mathematics 2014-05-06 Na Huang , Pengcheng Niu

We are concerned with the similarity problem for Cowen-Douglas operator tuples. The unitary equivalence counterpart was already investigated in the 1970's and geometric concepts including vector bundles and curvature appeared in the…

Functional Analysis · Mathematics 2022-12-09 Kui Ji , Shanshan Ji , Hyun-Kyoung Kwon , Jing Xu

We develope new lower bounds for the $A$-numerical radius of semi-Hilbertian space operators, and applying these bounds we obtain upper bounds for the $A$-numerical radius of the commutators of operators. The bounds obtained here improve on…

Functional Analysis · Mathematics 2024-08-14 Pintu Bhunia , Kallol Paul

We introduce a set of operator-valued invariants for localization of operator tuples in the Cowen-Douglas class, with which a Specht-type criterion for unitary equivalence is obtained.

Functional Analysis · Mathematics 2021-02-24 Li Chen

In this paper the complete solution of the restricted inequalities for supremal operators are given. The boundedness of the composition of supremal operators with the Hardy and Copson operators in weighted Lebesgue spaces are characterized.

Functional Analysis · Mathematics 2020-02-05 Amiran Gogatishvili , Rza Mustafayev

We study interpolating sequences of $d$-tuples of matrices, by looking at the commuting and the non-commuting case separately. In both cases, we will give a characterization of such sequences in terms of separation conditions on suitable…

Complex Variables · Mathematics 2021-06-02 Alberto Dayan

In this article, we investigate the ball version of von Neumann inequality for the class of doubly contractive $d$-tuple of weighted shift. We show that if the weighted shift is balanced or satisfies an appropriate weight condition, then it…

Functional Analysis · Mathematics 2026-04-14 Soumyadip Dey , Rajeev Gupta , Surjit Kumar

We derive inequalities for sums of eigenvalues of Schr\"{o}dinger operators on finite intervals and tori. In the first of these cases, the inequalities converge to the classical trace formulae in the limit as the number of eigenvalues…

Spectral Theory · Mathematics 2016-05-09 Pedro Freitas , James B. Kennedy

General approach to the multiplication or adjoint operation of $2\times 2$ block operator matrices with unbounded entries are founded. Furthermore, criteria for self-adjointness of block operator matrices based on their entry operators are…

Functional Analysis · Mathematics 2014-04-01 Guohai Jin , Alatancang Chen

Let $\mathbb{A}=\left( \begin{array}{cc} A & 0 \\ 0 & A \\ \end{array} \right)$ be the $2\times2$ diagonal operator matrix determined by a positive bounded operator $A$. For semi-Hilbertian operators $X$ and $Y$, we first show that…

Functional Analysis · Mathematics 2020-05-12 Qingxiang Xu , Zhongming Ye , Ali Zamani

Some inequalities for positive linear maps on matrix algebras are given, especially asymmetric extensions of Kadison's inequality and several operator versions of Chebyshev's inequality. We also discuss well-known results around the matrix…

Functional Analysis · Mathematics 2010-03-12 Jean-Christophe Bourin , Éric Ricard

In this paper we study eigenvalues of Laplacian and biharmonic operators on compact domains in complete manifolds. We establish several new inequalities for eigenvalues of Laplacian and biharmonic operators respectively by using Sobolev…

Differential Geometry · Mathematics 2024-12-23 Yong Luo , Xianjing Zheng