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Related papers: Operator extensions of Hua's inequality

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We present a new operator equality in the framework of Hilbert $C^*$-modules. As a consequence, we get an extension of the Euler--Lagrange type identity in the setting of Hilbert bundles as well as several generalized operator Bohr's…

Operator Algebras · Mathematics 2010-05-31 M. S. Moslehian , R. Rajic

Recently proved weighted Cauchy Scwarz inequality for Hilbert $C^*$-modules leads to many H\"older type inequalities for unitarily invariant norms on Hilbert space operators.

Functional Analysis · Mathematics 2019-07-02 Dragoljub J. Kečkić

Jensen's operator inequality for convexifiable functions is obtained. This result contains classical Jensen's operator inequality as a particular case. As a consequence, a new refinement and a reverse of Young's inequality is given.

Functional Analysis · Mathematics 2018-01-11 Hamid Reza Moradi , Shigeru Furuichi , Flavia-Corina Mitroi-Symeonidis , Razieh Naseri

The H$\ddot{{\rm o}}$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 to extend this convex inequality to the Hilbert…

Functional Analysis · Mathematics 2025-03-03 Kangjian Wu , Jia Li , Qingxiang Xu

We establish what we consider to be the definitive versions of Jensen's operator inequality and Jensen's trace inequality for functions defined on an interval. This is accomplished by the introduction of genuine non-commutative convex…

Operator Algebras · Mathematics 2007-05-23 Frank Hansen , Gert K. Pedersen

In this paper, we state some characterizations of $h$-convex function is defined on a convex set in a linear space. By doing so, we extend the Jensen-Mercer inequality for $h$-convex function. We will also define $h$-convex function for…

Functional Analysis · Mathematics 2020-03-31 M. Abbasi , A. Morassaei , F. Mirzapour

In the first part of the paper, we use states on $C^*$-algebras in order to establish some equivalent statements to equality in the triangle inequality, as well as to the parallelogram identity for elements of a pre-Hilbert $C^*$-module. We…

Functional Analysis · Mathematics 2021-07-23 Rasoul Eskandari , M. S. Moslehian , Dan Popovici

Mercer inequality for convex functions is a variant of Jensen's inequality, with an operator version that is still valid without operator convexity. This paper is two folded. First, we present a Mercer-type inequality for operators without…

Functional Analysis · Mathematics 2020-03-06 H. R. Moradi , S. Furuichi , M. Sababheh

The parallel sum for adjoinable operators on Hilbert $C^*$-modules is introduced and studied. Some results known for matrices and bounded linear operators on Hilbert spaces are generalized to the case of adjointable operators on Hilbert…

Operator Algebras · Mathematics 2018-07-16 Wei Luo , Chuanning Song , Qingxiang Xu

We study the Mercer inequality and its operator extension for superquadratic functions. In particular, we give a more general form of the Mercer inequality by replacing some constants by positive operators. As some consequences, our results…

Functional Analysis · Mathematics 2024-03-27 Mohsen Kian , Zainab Peymani Mazraj

In this work, an operator superquadratic function (in operator sense) for positive Hilbert space operators is defined. Several examples with some important properties together with some observations which are related to the operator…

Functional Analysis · Mathematics 2019-12-17 M. W. Alomari

The main purpose of this paper is, in the general setting of the adjointable operators on Hilbert $C^*$-modules, to develop two new tools that can be applied to deal with the positive solutions of certain operator equations, the operator…

Functional Analysis · Mathematics 2024-06-14 Mohammad Sababheh , Hamid Reza Moradi , Qingxiang Xu , Shuo Zhao

We establish an operator extension of the following generalization of Bohr's inequality, due to M.P. Vasi\'c and D.J. Ke\v{c}ki\'{c}: $$|\sum_{i=1}^n z_i|^r \leq (\sum_{i=1}^n \alpha_i^{1/(1-r)})^{r-1}\sum_{i=1}^n \alpha_i|z_i|^r \quad…

Operator Algebras · Mathematics 2010-05-31 M. S. Moslehian , J. Pecaric , I. Peric

We continue our study of the general theory of possibly nonselfadjoint algebras of operators on a Hilbert space, and modules over such algebras, developing a little more technology to connect `nonselfadjoint operator algebra' with the…

Operator Algebras · Mathematics 2007-05-23 David P. Blecher

This paper is mainly devoted to studying operator Jensen inequality. More precisely, a new generalization of Jensen inequality and its reverse version for convex (not necessary operator convex) functions have been proved. Several special…

Functional Analysis · Mathematics 2019-06-10 M. Shah Hosseini , H. R. Moradi , B. Moosavi

Considering the deeper reasons of the appearance of a remarkable counterexample by J.~Kaad and M.~Skeide [17] we consider situations in which two Hilbert C*-modules $M \subset N$ with $M^\bot = \{ 0 \}$ over a fixed C*-algebra $A$ of…

Operator Algebras · Mathematics 2026-04-07 Michael Frank

This article improves the triangle inequality for complex numbers, using the Hermite-Hadamard inequality for convex functions. Then, applications of the obtained refinement are presented to include some operator inequalities. The operator…

Functional Analysis · Mathematics 2022-04-19 Shigeru Furuichi , Mohammad Sababheh , Hamid Reza Moradi

We extend a work of Pedersen and Takesaki by giving some equivalent conditions for the existence of a positive solution of the so-called Pedersen--Takesaki operator equation $XHX=K$ in the setting of Hilbert $C^*$-modules. It is known that…

Operator Algebras · Mathematics 2021-11-25 R. Eskandari , X. Fang , M. S. Moslehian , Q. Xu

Let $\mathcal{A}$ be a $C^*$-algebra and $\phi:\cA\to L(H)$ be a positive unital map. Then, for a convex function $f:I\to \mathbb{R}$ defined on some open interval and a self-adjoint element $a\in \mathcal{A}$ whose spectrum lies in $I$, we…

Functional Analysis · Mathematics 2007-05-23 Jorge Antezana , Pedro Massey , Demetrio Stojanoff

We apply the inequality $\left|\left<x,y\right>\right|\le\|x\|\,\left<y,y\right>^{1/2}$ to give an easy and elementary proof of many operator inequalities for elementary operators and inner type product integral transformers obtained during…

Functional Analysis · Mathematics 2018-01-25 Dragoljub J. Kečkić
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