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Related papers: Operator inequalities related to weak 2-positivity

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We continue our study of operator algebras with contractive approximate identities (cais) by presenting a couple of interesting examples of operator algebras with cais, which in particular answer questions raised in previous papers in this…

Operator Algebras · Mathematics 2014-07-08 David P. Blecher , Charles John Read

We give some new characterizations of almost weak Dunford-Pettis operators and we investigate their relationship with weak Dunford-Pettis operators.

Functional Analysis · Mathematics 2016-10-14 Nabil Machrafi , Aziz Elbour , Mohammed Moussa

A version of the Cauchy-Schwarz inequality in operator theory is the following: for any two symmetric, positive definite matrices $A,B \in \mathbb{R}^{n \times n}$ and arbitrary $X \in \mathbb{R}^{n \times n}$ $$ \|AXB\| \leq \|A^2…

Functional Analysis · Mathematics 2016-08-18 Stefan Steinerberger

Well-known subadditivity results for positive operators (of Brown-Kosaki and Rotfeld/Ando-Zhan types) are extended to Hermitian and normal ones. Applications to Cartesian decomposition and block-matrices are given.

Functional Analysis · Mathematics 2009-06-09 jean-Christophe Bourin

In this paper, we show refined Young inequalities for two positive operators. Our results refine the ordering relations among the arithmetic mean, the geometric mean and the harmonic mean for two positive operators. In addition, we give two…

Functional Analysis · Mathematics 2011-04-26 Shigeru Furuichi

Weakly centered and spectrally weakly cenetered weighted composition operators in $L^2$-spaces are characterized. Criteria for existence of invariant subspaces are given. Additional results and examples are supplied.

Functional Analysis · Mathematics 2025-10-23 Piotr Budzyński

We prove a simple sufficient criteria to obtain some Hardy inequalities on Riemannian manifolds related to quasilinear second-order differential operator $\Delta_{p}u := \Div(\abs{\nabla u}^{p-2}\nabla u)$. Namely, if $\rho$ is a…

Analysis of PDEs · Mathematics 2013-04-16 Lorenzo D'Ambrosio , Serena Dipierro

We characterize two weight inequalities for general positive dyadic operators. We consider both weak and strong type inequalities, and general (p,q) mapping properties. Special cases include Sawyers Fractional Integral operator results from…

Classical Analysis and ODEs · Mathematics 2010-11-29 Michael T. Lacey , Eric T. Sawyer , Ignacio Uriarte-Tuero

We establish a set of relations between several quite diverse types of weighted inequalities involving various integral operators and fairly general quasinorm-like functionals which we call sub-monotone. The main result enables one to solve…

Classical Analysis and ODEs · Mathematics 2025-03-13 Amiran Gogatishvili , Luboš Pick

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

Weak-type quasi-norms are defined using the mean oscillation or the mean of a function on dyadic cubes, providing discrete analogues and variants of the corresponding quasi-norms on the upper half-space previously considered in the…

Functional Analysis · Mathematics 2025-06-27 Galia Dafni , Shahaboddin Shaabani

We develop a new proof of the result of L.-E.~Persson and V.D.~Stepanov \cite[Theorems 1 and 3]{Per:02}, which provides a characterization of a Hardy integral inequality involving two weights, and which can be applied to an effective…

Functional Analysis · Mathematics 2025-07-02 Amiran Gogatishvili , Luboš Pick , Hana Turčinová , Tuğçe Ünver

Some exact formulae of the expectation values and probability densities in a weak measurement for an operator ${\bf A}$ which satisfies the property ${\bf A}^{2}=1$ are derived. These formulae include all-order effects of the unitary…

Quantum Physics · Physics 2012-05-24 Kouji Nakamura , Atsushi Nishizawa , Masa-Katsu Fujimoto

This paper provides conditions (i) to distinguish weak supercyclicity form supercyclicity for operators acting on normed and Banach spaces, and also (ii) to ensure when weak supercyclicity implies weak stability.

Functional Analysis · Mathematics 2021-01-26 C. S. Kubrusly , B. P. Duggal

In this paper, a class of generalized backward doubly stochastic differential equations whose coefficient contains the subdifferential operators of two convex functions (also called generalized backward doubly stochastic variational…

Probability · Mathematics 2011-08-04 Yong Ren , Qing Zhou , Auguste Aman

We study the existence of negative eigenvalues for two-dimensional Schr\"odinger operators with real-valued potentials in the weak coupling regime. In his pioneering paper [Simon 1976] from half a century ago, Simon was the first to…

Spectral Theory · Mathematics 2026-04-22 Jussi Behrndt , Petr Siegl , Nicolas Weber

In this paper, we introduce the concept of a pseudo weakly compact operator of order $ p $ between Banach spaces. Also we study the notion of $ p $-Dunford-Pettis relatively compact property which is in "general" weaker than the…

Functional Analysis · Mathematics 2018-10-15 M. Alikhani

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 develop a systematic approach to establish Bell inequalities for qubits based on the Cauchy-Schwarz inequality. We also use the concept of distinct "roots" of Bell function to classify some well-known Bell inequalities for qubits. As…

Quantum Physics · Physics 2015-05-13 Jing-Ling Chen , Dong-Ling Deng

In this paper, we consider a two-variable operator function that includes two weighted spectral geometric means, and show fundamental properties of the operator function. Moreover, it satisfies the Ando-Hiai type inequality under some…

Functional Analysis · Mathematics 2025-12-30 Yuki Seo , Shuhei Wada , Takeaki Yamazaki