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Related papers: Quojections without Banach subspaces

200 papers

We show that the Banach space $C(K,X)$ is subprojective if $K$ is scattered and $X$ is subprojective.

Functional Analysis · Mathematics 2019-03-25 Manuel González , Javier Pello

We consider the method of alternating (metric) projections for pairs of linear subspaces of finite dimensional Banach spaces. We investigate the size of the set of points for which this method converges to the metric projection onto the…

Functional Analysis · Mathematics 2023-06-01 Christian Bargetz , Franz Luggin

We show that every Banach space $X$ containing an isomorphic copy of $c_0$ has an infinite equilateral set and also that if $X$ has a bounded biorthogonal system of size $\alpha$ then it can be renormed so as to admit an equilateral set of…

Functional Analysis · Mathematics 2013-04-25 S. K. Mercourakis , G. Vassiliadis

We generalize the classical coorbit space theory developed by Feichtinger and Gr"ochenig to quasi-Banach spaces. As a main result we provide atomic decompositions for coorbit spaces defined with respect to quasi-Banach spaces. These atomic…

Functional Analysis · Mathematics 2007-05-23 Holger Rauhut

We construct a complete metric space $M$ of cardinality continuum such that every non-singleton closed separable subset of $M$ fails to be a Lipschitz retract of $M$. This provides a metric analogue to the various classical and recent…

Functional Analysis · Mathematics 2022-06-22 Petr Hájek , Andrés Quilis

We investigate a method for producing concrete convex-transitive Banach spaces. The gist of the method is in getting rid of dissymmetries of a given space by taking a carefully chosen quotient. The spaces of interest here are typically…

Functional Analysis · Mathematics 2011-06-08 Jarno Talponen

In the present paper we prove that a necessary condition for a Banach space $X$ to admit a generating compact Lipschitz retract $K$, which satisfies an additional mild assumption on its shape, is that $X$ enjoys the Bounded Approximation…

Functional Analysis · Mathematics 2022-02-17 Petr Hájek , Rubén Medina

The paper is concerned with the problem whether a nonseparable Banach space must contain an uncountable set of vectors such that the distances between every two distinct vectors of the set are the same. Such sets are called equilateral. We…

Functional Analysis · Mathematics 2015-04-21 Piotr Koszmider

We review the current state of the homogeneous Banach space problem. We then formulate several questions which arise naturally from this problem, some of which seem to be fundamental but new. We give many examples defining the bounds on the…

Functional Analysis · Mathematics 2016-09-06 Peter G. Casazza

We study the extremality of nonexpansive mappings on a nonempty bounded closed and convex subset of a normed space (therein specific Banach spaces). We show that surjective isometries are extremal in this sense for many Banach spaces,…

Functional Analysis · Mathematics 2025-02-06 Christian Bargetz , Michael Dymond , Katriin Pirk

We show that there is an operator space notion of Lipschitz embeddability between operator spaces which is strictly weaker than its linear counterpart but which is still strong enough to impose linear restrictions on operator space…

Operator Algebras · Mathematics 2022-11-28 Bruno de Mendonça Braga , Javier Alejandro Chávez-Domínguez , Thomas Sinclair

For an unbounded operator $S$ on a Banach space the existence of invariant subspaces corresponding to its spectrum in the left and right half-plane is proved. The general assumption on $S$ is the uniform boundedness of the resolvent along…

Functional Analysis · Mathematics 2015-04-21 Monika Winklmeier , Christian Wyss

Working in infinite dimensional linear spaces, we deal with support for closed sets without interior. We generalize the Convexity Theorem for closed sets without interior. Finally we study the infinite dimensional version of Jordan…

Functional Analysis · Mathematics 2023-03-14 Paolo d'Alessandro

The article is devoted to topological homeomorphisms of Banach spaces over complete non-Archimedean normed infinite fields with products of copies of the fields.

Algebraic Topology · Mathematics 2018-12-18 Sergey V. Ludkovsky

In the nonlinear geometry of Banach spaces where the objects in the category are Banach spaces as in the linear case, the morphisms in the new setting are taken to comprise of certain nonlinear maps involving say, Lipschitz maps and, in…

Functional Analysis · Mathematics 2023-12-12 M. A. Sofi

This article is a continuation of a paper of the first author \cite{F} about complex structures on real Banach spaces. We define a notion of even infinite dimensional real Banach space, and prove that there exist even spaces, including HI…

Functional Analysis · Mathematics 2007-05-23 Valentin Ferenczi , Eloi Medina Galego

It is proved that there exist complemented subspaces of countable topological products (locally convex direct sums) of Banach spaces which cannot be represented as topological products (locally convex direct sums) of Banach spaces. (This is…

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

We prove several results concerning the representation of projections on arbitrary Banach spaces. We also give illustrative examples including an example of a generalized bi-circular projection which can not be written as the average of the…

Functional Analysis · Mathematics 2012-11-02 A. B. Abubaker , Fernanda Botelho , James Jamison

We show that for infinite Tychonoff spaces X and Y the weak*-dual of Ck(X x Y) contains a basic sequence; moreover, the weak*-bidual of Ck(X) contains such a sequence as well. When X and Y are infinite compact spaces, we single out a…

Functional Analysis · Mathematics 2026-01-28 Jerzy Kakol , Manuel Lopez-Pellicer , Wieslaw Sliwa

In this survey, we discuss the definition of a (quasi-)Banach function space. We advertise the original definition by Zaanen and Luxemburg, which does not have various issues introduced by other, subsequent definitions. Moreover, we prove…

Functional Analysis · Mathematics 2024-05-31 Emiel Lorist , Zoe Nieraeth