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We present new upper and lower bounds for the numerical radius of a bounded linear operator defined on a complex Hilbert space, which improve on the existing bounds. Among many other inequalities proved in this article, we show that for a…

Functional Analysis · Mathematics 2024-08-13 Pintu Bhunia , Kallol Paul , Raj kumar Nayak

In this paper, we establish some new integral inequalities for for m- and (alpha,m)-logarithmically convex functions.

Classical Analysis and ODEs · Mathematics 2012-11-29 Mevlut Tunc

We extend some inequalities for normal matrices and positive linear maps related to the Russo-Dye theorem. The results cover the case of some positive linear maps on a von Neumann algebra mapping any nonzero operator to an unbounded…

Operator Algebras · Mathematics 2020-04-24 Jean-Christophe Bourin , Jingjing Shao

We prove several numerical radius inequalities for linear operators in Hilbert spaces. It is shown, among other inequalities, that if $A$ is a bounded linear operator on a complex Hilbert space, then \[\omega \left( A \right)\le…

Functional Analysis · Mathematics 2021-06-15 Farzaneh Pouladi Najafabadi , Hamid Reza Moradi

In this paper, we establish various inequalities for some mappings that are linked with the illustrious Hermite-Hadamard integral inequality for mappings whose absolute values belong to the class K?;s m;1 and K?;s m;2.

Classical Analysis and ODEs · Mathematics 2013-08-20 Muhammad Muddassar , Ahsan Ali

In this article we consider means of positive bounded linear operators on a Hilbert space. We present a complete theory that provides a framework which extends the theory of the Karcher mean, its approximating matrix power means, and a…

Functional Analysis · Mathematics 2016-01-27 Miklós Pálfia

In this article, we present some new inequalities for numerical radius of Hilbert space operators via convex functions. Our results generalize and improve earlier results by El-Haddad and Kittaneh. Among several results, we show that if…

Functional Analysis · Mathematics 2019-07-16 S. Tafazoli , H. R. Moradi , S. Furuichi , P. Harikrishnan

Let $\mathcal{H}$ be a complex Hilbert space and $T:\mathcal{H}\to \mathcal{H}$ be a contraction. Let $$A_nf=\frac{1}{n}\sum_{j=1}^nT^jf$$ for $f\in \mathcal{H}$. Let $(n_k)$ be a lacunary sequence, then there exists a constant $C_1>0$ such…

Classical Analysis and ODEs · Mathematics 2025-06-24 Sakin Demir

In this paper, we give some reverse-types of Ando's and H\"older-McCarthy's inequalities for positive linear maps, and positive invertible operators. For our purpose, we use a recently improved Young inequality and its reverse.

Functional Analysis · Mathematics 2018-05-29 M. Hajmohamadi , R. Lashkaripour , M. Bakherad

We revisit and prove some convexity inequalities for trace functions conjectured in the earlier part I. The main functional considered is \Phi_{p,q}(A_1,A_2,...,A_m) = (trace((\sum_{j=1}^m A_j^p)^{q/p}))^{1/q} for m positive definite…

Operator Algebras · Mathematics 2008-02-25 Eric A. Carlen , Elliott H. Lieb

Several matrix/operator inequalies are given. Most of them are unexpected extensions of the Araki Log-majorization theorem, obtained thanks to a new log-majorization for positive linear maps and normal operators (Theorem 2.9). The main idea…

Functional Analysis · Mathematics 2016-06-14 Jean-Christophe Bourin , Eun-Young Lee

An operator C on a Hilbert space H dilates to an operator T on a Hilbert space K if there is an isometry V from H to K such that C=V^*TV. A main result of this paper is, for a positive integer d, the simultaneous dilation, up to a sharp…

Functional Analysis · Mathematics 2019-06-05 J. William Helton , Igor Klep , Scott A. McCullough , Markus Schweighofer

We give a general formulation of Jensen's operator inequality for unital fields of positive linear mappings, and we consider different types of converse inequalities.

Operator Algebras · Mathematics 2008-08-11 Frank Hansen , Josip Pecaric , Ivan Peric

Let $(\mathcal{X}, d, \mu)$ be a metric measure space, $L$ a linear operator which has a bounded $H_\infty$ functional calculus and satisfies the Davies-Gaffney estimate, $\Phi$ a concave function on $(0,\infty)$ of critical lower type…

Classical Analysis and ODEs · Mathematics 2015-01-14 Yiyu Liang , Dachun Yang , Wen Yuan

We present positive maps and matrix inequalities for variables from the positive cone. These inequalities contain partial transpose and reshuffling operations, and can be understood as positive multilinear maps that are in one-to-one…

Quantum Physics · Physics 2024-03-08 Maria Balanzó-Juandó , Michał Studziński , Felix Huber

Let $\varphi$ be a normal state on the algebra $B(H)$ of all bounded operators on a Hilbert space $H$, $f$ a strictly positive, continuous function on $(0, \infty)$, and let $g$ be a function on $(0, \infty)$ defined by $g(t) =…

Functional Analysis · Mathematics 2012-07-24 Dinh Trung Hoa , Hiroyuki Osaka , Jun Tomiyama

We establish two global subellipticity properties of positive symmetric second-order partial differential operators on $L_2(\Ri^d)$. First, if $m \in \Ni$ then we consider operators $H_0$ with coefficients in $W^{m+1,\infty}(\Ri^d)$ and…

Analysis of PDEs · Mathematics 2014-01-03 A. F. M. ter Elst , Derek W. Robinson

Let $\mathcal{B}(\mathcal{H})$ be the algebra of all bounded linear operators on a complex Hilbert space $\mathcal{H}$. In this paper, we first establish several sharp improved and refined versions of the Bohr's inequality for the functions…

Functional Analysis · Mathematics 2026-04-15 Vasudevarao Allu , Himadri Halder

We show that Lieb's concavity theorem holds more generally for any unitarily invariant matrix function $\phi:\mathbf{H}^n_+\rightarrow \mathbb{R}$ that is monotone and concave. Concretely, we prove the joint concavity of the function $(A,B)…

Functional Analysis · Mathematics 2019-06-04 De Huang

We prove mixed inequalities for commutators of Calder\'on-Zygmund operators (CZO) with multilinear symbols. Concretely, let $m\in\mathbb{N}$ and $\mathbf{b}=(b_1,b_2,\dots, b_m)$ be a vectorial symbol such that each component $b_i\in…

Classical Analysis and ODEs · Mathematics 2021-08-23 Fabio Berra , Marilina Carena , Gladis Pradolini
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