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Given two Banach function spaces we study the pointwise product space E.F, especially for the case that the pointwise product of their unit balls is again convex. We then give conditions on when the pointwise product E . M(E, F)=F, where…

Functional Analysis · Mathematics 2008-04-01 Anton R. Schep

Suppose $X$ and $Y$ are Banach spaces, and ${\mathcal{I}}$, ${\mathcal{J}}$ are operator ideals (for instance, the ideals of strictly singular, weakly compact, or compact operators). Under what conditions does the inclusion…

Operator Algebras · Mathematics 2013-09-24 T. Oikhberg , E. Spinu

In this paper we characterize when the product of two block Toeplitz operators is a compact perturbation of a block Toeplitz operator on the Hardy space of the open unit disk. Necessary and sufficient conditions are given for the commutator…

Functional Analysis · Mathematics 2009-09-25 Caixing Gu , Dechao Zheng

We show that if $T$ is a narrow operator on $X=X_{1}\oplus_{1} X_{2}$ or $X=X_{1}\oplus_{\infty} X_{2}$, then the restrictions to $X_{1}$ and $X_{2}$ are narrow and conversely. We also characterise by a version of the Daugavet property for…

Functional Analysis · Mathematics 2021-10-05 Dmitriy Bilik , Vladimir Kadets , Roman Shvidkoy , Dirk Werner

We study operators carrying disjoint bounded subsets of a Banach lattice into compact, weakly compact, and limited subsets of a Banach space. Surprisingly, these operators behave differently with classical compact, weakly compact, and…

Functional Analysis · Mathematics 2024-10-01 Eduard Emelyanov , Nazife Erkurşun-Özcan , Svetlana Gorokhova

We prove that if $X,Y$ are Banach spaces, $\Omega$ a compact Hausdorff space and $U\hbox{\rm :} C(\Omega,X)\to Y$ is a bounded linear operator, and if $U$ is a Dunford--Pettis operator the range of the representing measure $G(\Sigma)…

Functional Analysis · Mathematics 2007-05-23 Dumitru Popa

Using the hierarchy of weakly null sequences introduced by Argyros, Merkourakis, and Tsarpalias, we introduce two new families of operator classes. The first family simultaneously generalizes the completely continuous operators and the weak…

Functional Analysis · Mathematics 2018-10-15 R. M. Causey

In this article, we study the relationship between \(p\)-\((V)\) subsets and p-\(V^*\) subsets of dual spaces. We investigate the Banach space X with the property that adjoint every \(p\)-convergent operator \(T: X \rightarrow Y\) is weakly…

Functional Analysis · Mathematics 2019-05-10 M. Alikhani

We consider a class of bounded linear operators between Banach spaces, which we call operators with the Kato property, that includes the family of strictly singular operators between those spaces. We show that if $T:E\to F$ is a dense-range…

Functional Analysis · Mathematics 2025-06-30 Mar Jiménez Sevilla , Sebastián Lajara López , Miguel Ángel Ruiz Risueño

We characterize the positive Schur property in the positive projective tensor products of Banach lattices, we establish the connection with the weak operator topology and we give necessary and sufficient conditions for the space of regular…

Functional Analysis · Mathematics 2020-09-16 Geraldo Botelho , Qingying Bu , Khazhak Navoyan

A set of bounded linear operators from a Banach space to a Banach lattice is collectively L-weakly compact whenever union of images of the unit ball is L-weakly compact. We extend the Meyer-Nieberg duality theorem to collectively L-weakly…

Functional Analysis · Mathematics 2024-10-29 Eduard Emelyanov

We give a characterization of compact and Fredholm operators on polyanalytic Fock spaces in terms of limit operators. As an application we obtain a generalization of the Bauer-Isralowitz theorem using a matrix valued Berezin type transform.…

Functional Analysis · Mathematics 2022-09-21 Raffael Hagger

In this paper, we characterize Banach lattices on which each Dunford-Pettis operator (or weak Dunford-Pettis) is unbounded absolute weak Dunford-Pettis operator and the converse.

Functional Analysis · Mathematics 2020-06-23 Hui Li , Zili Chen

We prove an extrapolation of compactness theorem for operators on Banach function spaces satisfying certain convexity and concavity conditions. In particular, we show that the boundedness of an operator $T$ in the weighted Lebesgue scale…

Classical Analysis and ODEs · Mathematics 2024-05-31 Emiel Lorist , Zoe Nieraeth

The paper investigates the variation of the spectrum of operators in infinite dimensional Banach spaces. In particular, it is shown that the spectrum function is Borel from the space of bounded operators on a separable Banach space;…

General Topology · Mathematics 2009-12-31 Mohammed Yahdi

We show that when $C(K)$ does not have few operator -- in the sense of Koszmider [P. Koszmider, Banach spaces of continuous functions with few operators. Math. Ann. 300 (2004), no. 1, 151 - 183.] -- the sets of operators which are not weak…

Functional Analysis · Mathematics 2012-08-06 Rogério Fajardo , Pedro Kaufmann , Leonardo Pellegrini

This paper is devoted to the study of two classes of operators related to disjointly weakly compact sets, which we call $DW$-DP operators and $DW$-limited operators, respectively. They carry disjointly weakly compact subsets of a Banach…

Functional Analysis · Mathematics 2024-12-03 Jin Xi Chen , Jingge Feng

We prove that the class of Banach function lattices in which all relatively weakly compact sets are equi-integrable sets (i.e. spaces satisfying the Dunford-Pettis criterion) coincides with the class of 1-disjointly homogeneous Banach…

Functional Analysis · Mathematics 2019-12-18 Karol Lesnik , Lech Maligranda , Jakub Tomaszewski

We prove that the class of positive operators from $L_\infty (\mu)$ to $L_1 (\nu)$ has the Bishop-Phelps-Bollob\'as property for any positive measures $\mu$ and $\nu$. The same result also holds for the pair $(c_0, \ell_1)$. We also provide…

Functional Analysis · Mathematics 2021-06-14 María D. Acosta , Maryam Soleimani-Mourchehkhorti

In this paper we study the norm-attainment of positive operators between Banach lattices. By considering an absolute version of James boundaries, we prove that: If $E$ is a reflexive Banach lattice whose order is given by a basis and $F$ is…

Functional Analysis · Mathematics 2025-07-03 José Lucas P. Luiz , Vinícius C. C. Miranda