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In this paper, two main results concerning uniformly continuous retractions are proved. First, an $\alpha$-H\"older retraction from any separable Banach space onto a compact convex subset whose closed linear span is the whole space is…

Functional Analysis · Mathematics 2022-05-26 Rubén Medina

In this paper, we introduce the notion of topologically Banach contraction mapping defined on an arbitrary topological space X with the help of a continuous function $g:X\times X\rightarrow \mathbb{R}$ and investigate the existence of fixed…

General Topology · Mathematics 2020-07-22 Sumit Som , Supriti Laha , Lakshmi Kanta Dey

Let $C$ be a convex subset of a locally convex space. We provide optimal approximate fixed point results for sequentially continuous maps $f\colon C\to\bar{C}$. First we prove that if $f(C)$ is totally bounded, then it has an approximate…

Functional Analysis · Mathematics 2013-02-27 Cleon S. Barroso , Ondřej F. K. Kalenda , Michel P. Rebouças

We study the generic behavior of the method of successive approximations for set-valued mappings in separable Banach spaces. We consider the case of nonexpansive mappings with convex and compact point images and show that for the typical…

Functional Analysis · Mathematics 2023-01-27 Christian Bargetz , Emir Medjic , Katriin Pirk

In a countably normed space which is a linear space equipped with a countable number of pair-wise compatible norms, we prove the existence of a common nearest point (in all norms) from a point outside a nonempty subset if this subset is…

Functional Analysis · Mathematics 2022-12-14 Moustafa M. Zakaria , Nashat Faried , Hany A. El-Sharkawy

It is well known in convex analysis that proximal mappings on Hilbert spaces are $1$-Lipschitz. In the present paper we show that proximal mappings on uniformly convex Banach spaces are uniformly continuous on bounded sets. Moreover, we…

Functional Analysis · Mathematics 2017-11-07 Miroslav Bacak , Ulrich Kohlenbach

In this paper, we prove the existence of fixed points of mappings satisfying the condition (Da), a kind of generalized nonexpansive mappings, on a weakly compact convex subset in a Banach space satisfying Opial's condition. And we use…

Functional Analysis · Mathematics 2020-07-07 Chang Il Rim , Jong Gyong Kim

In this paper, a strong convergence theorem for asymptotically nonexpansive mappings in a uniformly convex and smooth Banach space is proved by using metric projections. This theorem extends and improves the recent strong convergence…

Functional Analysis · Mathematics 2011-12-01 Hossein Dehghan

We prove the existence of a fixed point for mappings which satisfy some asymptotic nonexpansive conditions in Banach spaces which are either nearly uniformly convex or they satisfy that asymptotic centers of bounded sequences are compact.…

Functional Analysis · Mathematics 2022-01-11 Tomas Dominguez Benavides , Pepa Lorenzo

The main objective of this article is to provide an alternative approach to the central result of [Eldred, A. Anthony, Kirk, W. A., Veeramani, P., Proximal normal structure and relatively nonexpansive mappings, Studia Math., vol 171(3),…

Functional Analysis · Mathematics 2022-06-30 Abhik Digar , G. Sankara Raju Kosuru

It is shown that if $C$ is a nonempty convex and weakly compact subset of a Banach space $X$ with $M(X)>1$ and $T:C\rightarrow C$ satisfies condition $(C)$ or is continuous and satisfies condition $(C_{\lambda})$ for some $\lambda \in…

Functional Analysis · Mathematics 2015-11-24 Anna Betiuk-Pilarska , Andrzej Wiśnicki

The purpose of this paper is to study an implicit scheme for a representation of nonexpansive mappings on a closed convex subset of a smooth and uniformly convex Banach space with respect to a left regular sequence of means defined on an…

Functional Analysis · Mathematics 2015-06-10 Ebrahim Soori

Fixed points for uniformly local asymptotic nonexpansive maps are discussed in this article. An approximate fixed point sequence for such a map over a uniformly convex Banach space is derived. At the end, we study the unique fixed point for…

Functional Analysis · Mathematics 2023-03-21 Pallab Maiti , Asrifa Sultana

We study universal approximation of continuous functionals on compact subsets of products of Hilbert spaces. We prove that any such functional can be uniformly approximated by models that first take finitely many continuous linear…

Machine Learning · Computer Science 2026-02-04 Andrey Krylov , Maksim Penkin

We consider a new type of mappings in metric spaces which can be characterized as mappings contracting perimeters of triangles. It is shown that such mappings are continuous. The fixed-point theorem for such mappings is proved and the…

General Topology · Mathematics 2023-08-03 Evgeniy Petrov

It is shown that a Banach space with locally uniformly convex dual admits an equivalent norm which is itself locally uniformly convex. It follows that on any such space all continuous real-valued functions may be uniformly approximated by…

Functional Analysis · Mathematics 2007-05-23 Richard Haydon

In this paper we address the question whether in a given Banach space, a Chebyshev center of a nonempty bounded subset can be a farthest point of the set. Our exploration reveals that the answer depends on the convexity properties of the…

Functional Analysis · Mathematics 2024-07-30 Debmalya Sain , Vladimir Kadets , Kallol Paul , Anubhab Ray

Non-convex functions that yet satisfy a condition of uniform convexity for non-close points can arise in discrete constructions. We prove that this sort of discrete uniform convexity is inherited by the convex envelope, which is the key to…

Functional Analysis · Mathematics 2021-05-12 Guillaume Grelier , Matías Raja

For any non-trivial convex and bounded subset $C$ of a Banach space, we show that outside of a $\sigma$-porous subset of the space of non-expansive mappings $C\to C$, all mappings have the maximal Lipschitz constant one witnessed locally at…

Functional Analysis · Mathematics 2022-05-04 Michael Dymond

We find conditions for a smooth nonlinear map $f:U\rightarrow V$ between open subsets of Hilbert or Banach spaces to be locally convex in the sense that for some $c$ and each positive $\varepsilon<c$ the image $% f(B_\varepsilon(x))$ of…

Functional Analysis · Mathematics 2012-05-16 Iryna Banakh , Taras Banakh , Anatolij Plichko , Anatoliy Prykarpatsky
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