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Related papers: On weakly extremal structures in Banach spaces

200 papers

A Banach space (or its norm) is said to have the diameter $2$ property (D$2$P in short) if every nonempty relatively weakly open subset of its closed unit ball has diameter $2$. We construct an equivalent norm on $L_1[0,1]$ which is weakly…

Functional Analysis · Mathematics 2022-12-29 Olav Nygaard , Märt Põldvere , Stanimir Troyansky , Tauri Viil

This paper is devoted to the study of strongly quasinonexpansive mappings in an abstract space and a Banach space.

Functional Analysis · Mathematics 2020-12-29 Koji Aoyama , Kei Zembayashi

In this paper, we introduce and investigate the concepts of cyclically weakly amenable and point amenable. Then, we compare these concepts with the concepts of weakly amenable and cyclically amenable and find the relation between them. For…

Functional Analysis · Mathematics 2022-09-28 M. J. Mehdipour , A. Rejali

We deal with a notion of weak binormal and weak principal normal for non-smooth curves of the Euclidean space with finite total curvature and total absolute torsion. By means of piecewise linear methods, we first introduce the analogous…

Differential Geometry · Mathematics 2020-05-19 Domenico Mucci , Alberto Saracco

Two approaches to Lipschitz structures for any set are presented, studied and compared. The first approach is similar to the one proposed in Fraser, Jr. R. B., Axiom systems for Lipschitz structures, Fundamenta Mathematicae, (1970), where…

General Topology · Mathematics 2024-04-23 Tullio Valent

In this paper, we study the existence of the random approximations and fixed points for random almost lower semicontinuous operators defined on finite dimensional Banach spaces, which in addition, are condensing or 1-set-contractive. Our…

Probability · Mathematics 2015-07-13 Monica Patriche

We study almost L(M) weakly compact and order L(M) weakly compact operators in Banach spaces. Several further topics related to these operators are investigated.

Functional Analysis · Mathematics 2024-07-04 Safak Alpay , Svetlana Gorokhova

Here we consider a perturbation of continuous mappings on Banach spaces and investigate their image under various conditions. Consequently, we study the solvability of some classes of equations and inclusions. For these, we start by the…

Functional Analysis · Mathematics 2023-10-11 Kamal N. Soltanov

The space Weak L^1 consists of all measurable functions on [0,1] such that q(f) = sup_{c>0} c \lambda{t : |f(t)| > c} is finite, where \lambda denotes Lebesgue measure. Let \rho be the gauge functional of the unit ball {f : q(f) \leq 1} of…

Functional Analysis · Mathematics 2007-05-23 Denny H. Leung

The use of nonstandard methods to characterize properties of weak, strong and mixed extensions of congruences to ultrafilters has been the main topic of several recent papers. We show that similar methods can be used to characterize the…

We prove some results on weakly almost square Banach spaces and their relatives. On the one hand, we discuss weak almost squareness in the setting of Banach function spaces. More precisely, let $(\Omega,\Sigma)$ be a measurable space, let…

Functional Analysis · Mathematics 2023-01-20 José Rodríguez , Abraham Rueda Zoca

In this paper, we prove some theorems related to properties of generalized symmetric hybrid mappings in Banach spaces. Using Banach limits, we prove a fixed point theorem for symmetric generalized hybrid mappings in Banach spaces. Moreover,…

Functional Analysis · Mathematics 2014-11-25 Fridoun Moradlou , Sattar Alizadeh

In this article, we introduce the concept of weakly uniquely stationary representations. This framework enables us to investigate the complementability of closed subspaces within the context of continuous cohomology with coeffcients in…

Functional Analysis · Mathematics 2025-07-14 Mario Klisse

The aim of this paper is to establish strong convergence theorems for a strongly relatively nonexpansive sequence in a smooth and uniformly convex Banach space. Then we employ our results to approximate solutions of the zero point problem…

Functional Analysis · Mathematics 2020-12-29 Koji Aoyama , Yasunori Kimura , Fumiaki Kohsaka

The paper is devoted to obtaining conditions for the roughness of dichotomy in the Banach spaces. Deep analysis of the well known papers was considered. The main results also works for the case of unbounded operators.

Dynamical Systems · Mathematics 2023-09-06 O. Iskra , S. Dashkovskiy , A. Pokutniy , V. Slynko , Yu. Zahorulko

In this paper we find some necessary and sufficient conditions for a Banach algebra to be amenable or weakly amenable, by applying the homomorphisms on Banach algebras.

Functional Analysis · Mathematics 2007-05-23 M. Eshaghi Gordji

We prove in this short report that for arbitrary weak converging sequence of sigma-finite Borelian measures in the separable Banach space there is a compact embedded separable subspace such that this measures not only are concentrated in…

Functional Analysis · Mathematics 2015-05-26 E. Ostrovsky , L. Sirota

In this paper, our main goal is to define the class of weakly Demi Dunford-Pettis applications. We also study their relationship with the classes of weakly Dunford-Pettis and Demi Dunford-Pettis operators, including a condition where these…

Functional Analysis · Mathematics 2026-03-11 Joilson Ribeiro , Fabricio Santos

The main results of the paper: {\bf (1)} The dual Banach space $X^*$ contains a linear subspace $A\subset X^*$ such that the set $A^{(1)}$ of all limits of weak$^*$ convergent bounded nets in $A$ is a proper norm-dense subset of $X^*$ if…

Functional Analysis · Mathematics 2013-02-26 Mikhail I. Ostrovskii

We discuss some open problems in the Geometry of Banach spaces having Ramsey-theoretic flavor. The problems are exposed together with well known results related to them.

Functional Analysis · Mathematics 2011-05-11 Pandelis Dodos , Jordi Lopez-Abad , Stevo Todorcevic