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In this paper, we introduce the cone normed spaces and cone bounded linear mappings. Among other things, we prove the Baire category theorem and the Banach--Steinhaus theorem in cone normed spaces.

Functional Analysis · Mathematics 2009-12-08 M. Eshaghi Gordji , M. Ramezani , H. Baghani , H. Khodaei

The classical Baldwin-Lachlan characterization of uncountably categorical theories is known to fail in continuous logic in that not every inseparably categorical theory has a strongly minimal set. Here we investigate these issues by…

Logic · Mathematics 2022-08-12 James Hanson

We characterize non-reflexive Banach spaces by a low-distortion (resp. isometric) embeddability of a certain metric graph up to a renorming. Also we study non-linear sufficient conditions for $\ell_1^n$ being $(1+\varepsilon)$-isomorphic to…

Functional Analysis · Mathematics 2016-07-29 Antonin Prochazka

This paper is about the maximally monotone and quasidense subsets of the product of a real Banach space and its dual. We discuss six subclasses of the maximal monotone sets that are equivalent to the quasidense ones. We define the Gossez…

Functional Analysis · Mathematics 2025-10-08 Stephen Simons

We show that irreducible strongly continuous representations of $\mathrm{SL}(2,\mathbb{R})$ on certain Banach spaces are admissible and that the admissibility of Banach space representations of SL(2,R) and the invariant subspace problem are…

Representation Theory · Mathematics 2026-05-11 Francesca Astengo , Michael G. Cowling , Bianca Di Blasio

The linear isometries between weighted Banach spaces of continuous functions are considered. Some of well known theorems on isometries between spaces of continuous functions are proved and stated, but all they are in an appropriate form. In…

General Topology · Mathematics 2007-05-23 Martin At. Stanev

We obtain sharp approximation results for into nearisometries between Lp spaces and nearisometries into a Hilbert space. Our main theorem is the optimal approximation result for nearsurjective nearisometries between general Banach spaces.

Functional Analysis · Mathematics 2007-05-23 Peter Semrl , Jussi Vaisala

We analyze a definition of product of Banach spaces that is naturally associated by duality with an abstract notion of space of multiplication operators. This dual relation allows to understand several constructions coming from different…

Functional Analysis · Mathematics 2020-03-31 Enrique A. Sanchez-Perez

This is the survey of results about norm one projections and 1-complemented subspaces in K\"othe function spaces and Banach sequence spaces. The historical development of the theory is presented from the 1930's to the newest ideas. Proofs…

Functional Analysis · Mathematics 2007-05-23 Beata Randrianantoanina

In the first part of our note we prove that every Weakly Lindel\"of Determined (WLD) (in particular, every reflexive) non-separable Banach $X$ space contains two dense linear subspaces $Y$ and $Z$ that are not densely isomorphic. This means…

Functional Analysis · Mathematics 2020-06-08 Petr Hájek , Tommaso Russo

This is a companion paper to our previous one, Avatars of Stein's Theorem in the complex setting. In this previous paper, we gave a sufficient condition for an integrable function in the upper-half plane to have an integrable Bergman…

Classical Analysis and ODEs · Mathematics 2025-06-24 Aline Bonami , Sandrine Grellier , Benoît Sehba

A Banach space with a Schauder basis is said to be $\alpha$-minimal for some countable ordinal $\alpha$ if, for any two block subspaces, the Bourgain embeddability index of one into the other is at least $\alpha$. We prove a dichotomy that…

Functional Analysis · Mathematics 2011-04-19 Christian Rosendal

We prove a version of the Ando-Choi-Effros lifting theorem respecting subspaces, which in turn relies on Oja's principle of local reflexivity respecting subspaces. To achieve this, we first develop a theory of pairs of $M$-ideals. As a…

Functional Analysis · Mathematics 2019-07-03 Javier Alejandro Chávez-Domínguez

We show that the class of subspaces of c_0 is stable under Lipschitz isomorphisms. The main corollary is that any Banach space which is Lipschitz isomorphic to c_0 is linearly isomorphic to c_0.

Functional Analysis · Mathematics 2007-05-23 G. Godefroy , N. J. Kalton , G. Lancien

We give an intrinsic characterisation of the separable reflexive Banach spaces that embed into separable reflexive spaces with an unconditional basis all of whose normalised block sequences with the same growth rate are equivalent. This…

Functional Analysis · Mathematics 2011-06-03 Christian Rosendal

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

The Banach-Saks property is an important tool in analysis with applications ranging from partial differential equations (PDEs) to calculus of variations and probability theory. We survey the Banach-Saks property for $L^p$-spaces, with a…

Functional Analysis · Mathematics 2023-11-14 Guy Foghem

Let $(x_n)$ be a sequence in a Banach space $X$ which does not converge in norm, and let $E$ be an isomorphically precisely norming set for $X$ such that \[ \sum_n |x^*(x_{n+1}-x_n)|< \infty, \; \forall x^* \in E. \qquad (*) \] Then there…

Functional Analysis · Mathematics 2016-09-06 George Androulakis

A subset of a Banach space is called equilateral if the distances between any two of its distinct elements are the same. It is proved that there exist non-separable Banach spaces (in fact of density continuum) with no infinite equilateral…

Functional Analysis · Mathematics 2021-05-25 Piotr Koszmider , Hugh Wark

We show that any Banach space contains a continuum of non isomorphic subspaces or a minimal subspace. We define an ergodic Banach space $X$ as a space such that $E_0$ Borel reduces to isomorphism on the set of subspaces of $X$, and show…

Functional Analysis · Mathematics 2014-02-25 Valentin Ferenczi , Christian Rosendal