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We study the representation of non-weakly compact operators between $AL$-spaces. In this setting, we show that every operator admits a best approximant in the ideal of weakly compact operators. Using duality arguments, we extend this result…

Functional Analysis · Mathematics 2026-03-30 Antonio Acuaviva , Amir Bahman Nasseri

This paper is devoted to the study of $DW$-compact operators, that is, those operators which map disjointly weakly compact sets in a Banach lattice onto relatively compact sets. We show that $DW$-compact operators are precisely the…

Functional Analysis · Mathematics 2024-06-06 Jin Xi Chen , Jingge Feng

A pair of functions defined on a set X with values in a vector space E is said to be disjoint if at least one of the functions takes the value 0 at every point in X. An operator acting between vector-valued function spaces is disjointness…

Functional Analysis · Mathematics 2012-03-19 Denny H. Leung , Ya-Shu Wang

The paper is devoted to the relationship between almost limited operators and weakly compacts operators. We show that if $F$ is a $\sigma $-Dedekind complete Banach lattice then, every almost limited operator $T:E\rightarrow F $ is weakly…

Functional Analysis · Mathematics 2014-03-17 A. Elbour , N. Machrafi , M. Moussa

We investigate the extremal properties of the unit ball of $L(X)_w^*$, the dual space of bounded linear operators defined on a Banach space $X$ equipped with the numerical radius norm. As an application of the present study, we obtain a…

Functional Analysis · Mathematics 2026-04-07 Subhadip Pal , Saikat Roy , Debmalya Sain

In this paper, we study the boundedness and the compactness of the little Hankel operators $h_b$ with operator-valued symbols $b$ between different weighted vector-valued Bergman spaces on the open unit ball $\mathbb{B}_n$ in…

Complex Variables · Mathematics 2020-12-22 David Békollé , Hugues Olivier Defo , Edgar L. Tchoundja , Brett D. Wick

In this article, the class of all Dunford-Pettis $ p $-convergent operators and $ p $-Dunford-Pettis relatively compact property on Banach spaces are investigated. Moreover, we give some conditions on Banach spaces $ X $ and $ Y $ such that…

Functional Analysis · Mathematics 2019-05-06 M. Alikhani

We study boundedness and compactness of composition operators on weighted Bergman spaces of Dirichlet series. Particularly, we obtain in some specific cases, upper and lower bounds of the essential norm of these operators and a criterion of…

Functional Analysis · Mathematics 2014-01-30 Maxime Bailleul

Given any Banach space $X$ and any weak*-compact subset $K$ of $X^*$, we compute the Szlenk index of the weak*-closed, convex hull of $K$ as a function of the Szlenk index of $K$. Also as an application, we compute the Szlenk index of any…

Functional Analysis · Mathematics 2017-06-06 Ryan M Causey

This paper introduces statistical order convergence and its pointwise variant for sequences of order bounded operators between Riesz spaces. We establish fundamental properties: uniqueness of the limit, stability under lattice operations,…

Functional Analysis · Mathematics 2025-12-30 Abdullah Aydın , Erdal Bayram , İshak Aydın

The duality of uniform approximation property for Banach spaces is well known. In this note, we establish, under the assumption of local reflexivity, the duality of uniform approximation property in the category of operator spaces.

Operator Algebras · Mathematics 2014-10-28 Yanqi Qiu

We show that a positive operator between $L^p$-spaces is given by integration against a kernel function if and only if the image of each positive function has a lower semi-continuous representative with respect to a suitable topology. This…

Functional Analysis · Mathematics 2024-06-11 Moritz Gerlach , Jochen Glück

Let $g$ be an analytic function on the unit disc and consider the integration operator of the form $T_g f(z) = \int_0^z fg'\,d\zeta$. We show that on the spaces $H^1$ and $BMOA$ the operator $T_g$ is weakly compact if and only if it is…

Functional Analysis · Mathematics 2011-01-25 Jussi Laitila , Santeri Miihkinen , Pekka J. Nieminen

Well-bounded operators are linear operators on a Banach space $X$ that have an $AC[a,b]$ functional calculus for some interval $[a,b]$. A well-bounded operator is of type (B) if it can be written as an integral against a spectral family of…

Functional Analysis · Mathematics 2022-08-19 Alan Stoneham

In this work we provide a characterization of distinct type of (linear and non-linear) maps between Banach spaces in terms of the differentiability of certain class of Lipschitz functions. Our results are stated in an abstract bornological…

Functional Analysis · Mathematics 2021-10-04 Mohammed Bachir , Sebastián Tapia-García

We investigate possible quantifications of Banach-Saks sets and weak Banach-Saks sets of higher orders and their relations to other quantities. We prove a quantitative version of the characterization of weak $\xi$-Banach-Saks sets using…

Functional Analysis · Mathematics 2024-08-05 Zdeněk Silber

In this paper we study groups of positive operators on Banach lattices. If a certain factorization property holds for the elements of such a group, the group has a homomorphic image in the isometric positive operators which has the same…

Functional Analysis · Mathematics 2023-05-31 Marcel de Jeu , Marten Wortel

A Banach space E is said to have Property (w) if every (bounded linear) operator from E into E' is weakly compact. We give some interesting examples of James type Banach spaces with Property (w). We also consider the passing of Property (w)…

Functional Analysis · Mathematics 2016-09-06 Denny H. Leung

If a separable Banach space $X$ is such that for some nonquasireflexive Banach space $Y$ there exists a surjective strictly singular operator $T:X\to Y$ then for every countable ordinal $\alpha $ the dual of $X$ contains a subspace whose…

Functional Analysis · Mathematics 2010-09-07 Mikhail I. Ostrovskii

We study Birkhoff-James orthogonality of compact (bounded) linear operators between Hilbert spaces and Banach spaces. Applying the notion of semi-inner-products in normed linear spaces and some related geometric ideas, we generalize and…

Functional Analysis · Mathematics 2018-10-12 Debmalya Sain , Kallol Paul , Arpita Mal