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Related papers: Note on almost isometric ideals and local retracts…

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We introduce the notion of (almost isometric) local retracts in metric space as a natural non-linear version of the concepts of locally complemented and almost isometric ideals from Banach spaces. We prove that given two metric spaces…

Functional Analysis · Mathematics 2023-11-23 Andrés Quilis , Abraham Rueda Zoca

A natural class of ideals, almost isometric ideals, of Banach spaces is defined and studied. The motivation for working with this class of subspaces is our observation that they inherit diameter 2 properties and the Daugavet property.…

Functional Analysis · Mathematics 2013-06-21 Trond A. Abrahamsen , Vegard Lima , Olav Nygaard

We single out and study a natural class of Banach spaces -- almost square Banach spaces. In an almost square space we can find, given a finite set $x_1,x_2,\ldots,x_N$ in the unit sphere, a unit vector $y$ such that $\|x_i-y\|$ is almost…

Functional Analysis · Mathematics 2015-08-25 Trond A. Abrahamsen , Johann Langemets , Vegard Lima

Strong convergence of a new iterative process based on the Shrinking projection method to a common element of the set of common fixed points of an infinite family of relatively quasi-nonexpansive multivalued mappings and the solution set of…

Functional Analysis · Mathematics 2012-08-21 M. Eslamian

We present and study some transfinite versions of (almost isometric) ideals in Banach spaces. As these notions are closely related with Lindenstrauss and Gurari\u{\i} spaces respectively, we will present a similar characterization for…

Functional Analysis · Mathematics 2025-05-08 Esteban Martínez Vañó , Abraham Rueda Zoca

Given a separable Banach space $E$, we construct an extremely non-complex Banach space (i.e. a space satisfying that $\|Id + T^2\|=1+\|T^2\|$ for every bounded linear operator $T$ on it) whose dual contains $E^*$ as an $L$-summand. We also…

Functional Analysis · Mathematics 2010-01-29 Piotr Koszmider , Miguel Martin , Javier Meri

We study $M$-ideals of compact operators by means of the property~$(M)$ introduced in \cite{Kal-M}. Our main result states for a separable Banach space $X$ that the space of compact operators on $X$ is an $M$-ideal in the space of bounded…

Functional Analysis · Mathematics 2016-09-06 Nigel J. Kalton , Dirk Werner

We consider uncountable almost disjoint families of subsets of $\mathbb N$, the Johnson-Lindenstrauss Banach spaces $(\mathcal X_{\mathcal A}, \|\ \|_\infty)$ induced by them, and their natural equivalent renormings $(\mathcal X_{\mathcal…

Functional Analysis · Mathematics 2022-12-13 Osvaldo Guzmán , Michael Hrušák , Piotr Koszmider

We study the interplay between Banach space theory and theory of analytic P-ideals. Applying the observation that, up to isomorphism, all Banach spaces with unconditional bases can be constructed in a way very similar to the construction of…

Logic · Mathematics 2019-06-03 Piotr Borodulin-Nadzieja , Barnabás Farkas

We investigate a relations of almost isometric embedding and almost isometry between metric spaces and prove that with respect to these relations: (1) There is a countable universal metric space. (2) There may exist fewer than continuum…

Logic · Mathematics 2007-05-23 Menachem Kojman , Saharon Shelah

We construct a nonseparable Banach space $\mathcal X$ (actually, of density continuum) such that any uncountable subset $\mathcal Y$ of the unit sphere of $\mathcal X$ contains uncountably many points distant by less than $1$ (in fact, by…

Functional Analysis · Mathematics 2021-06-09 Piotr Koszmider

We show that finite dimensional Banach spaces fail to be uniformly non locally almost square. Moreover, we construct an equivalent almost square bidual norm on $\ell_\infty.$ As a consequence we get that every dual Banach space containing…

Functional Analysis · Mathematics 2020-03-10 Trond A. Abrahamsen , Petr Hájek , Stanimir Troyanski

We develop a theory of large scale geometry of metrisable topological groups that, in a significant number of cases, allows one to define and identify a unique quasi-isometry type intrinsic to the topological group. Moreover, this…

Group Theory · Mathematics 2014-03-14 Christian Rosendal

We introduce the notions of almost Lipschitz embeddability and nearly isometric embeddability. We prove that for $p\in [1,\infty]$, every proper subset of $L_p$ is almost Lipschitzly embeddable into a Banach space $X$ if and only if $X$…

Metric Geometry · Mathematics 2017-09-27 Florent Baudier , Gilles Lancien

In this paper, we extend the Banach contraction principle to metric-like as well as partial metric spaces (not essentially complete) equipped with an arbitrary binary relation. Thereafter, we derive some fixed point results which are…

General Mathematics · Mathematics 2016-12-19 Md Ahmadullah , Abdur Rauf Khan , Mohammad Imdad

For a fixed $K\gg 1$ and $n\in\mathbb{N}$, $n\gg 1$, we study metric spaces which admit embeddings with distortion $\le K$ into each $n$-dimensional Banach space. Classical examples include spaces embeddable into $\log n$-dimensional…

Functional Analysis · Mathematics 2016-08-10 Mikhail I. Ostrovskii , Beata Randrianantoanina

In this paper, using generalized metric projection, we propose a new extragradient method for finding a common element of the solutions set of a generalized equilibrium problem and a variational inequality for an $\alpha$-inverse-strongly…

Functional Analysis · Mathematics 2016-11-01 Zeynab Jouymandi , Fridoun Moradlou

In this study, we introduce a new iterative processes to approximate common fixed points of an infinite family of quasi-nonexpansive mappings and obtain a strongly convergent iterative sequence to the common fixed points of these mappings…

Functional Analysis · Mathematics 2015-02-24 K. Dogan , V. Karakaya

We construct a Banach space satisfying that the nearest point map (also called proximity mapping or metric projection) onto any compact and convex subset is continuous but not uniformly continuous. The space we construct is locally…

Functional Analysis · Mathematics 2024-02-08 Rubén Medina , Andrés Quilis

It is well known that fixed point problems of contractive-type mappings defined on cone metric spaces over Banach algebras are not equivalent to those in usual metric spaces (see [3] and [10]). In this framework, the novelty of the present…

Functional Analysis · Mathematics 2019-06-17 Cristian Daniel Alecsa
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