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We study the fundamental properties of pointwise semi-Lipschitz functions between asymmetric spaces, which are the natural asymmetric counterpart of pointwise Lipschitz functions. We also study the influence that partial symmetries of a…

Functional Analysis · Mathematics 2024-10-10 Estíbalitz Durand-Cartagena , Jesús Á. Jaramillo , Francisco Venegas M

Using a technique of adjoining an order unit to a normed linear space, we have characterized strictly convex spaces among normed linear spaces and Hilbert spaces among strictly convex Banach spaces respectively. This leads to a…

Functional Analysis · Mathematics 2022-01-20 Anil Kumar Karn

We investigate an extended version of Hilbert space of analytic functions called Hilbert space of complex-valued harmonic functions. It is found that functions in Hilbert space of complex-valued harmonic functions exhibit many properties…

Complex Variables · Mathematics 2024-10-30 Tseganesh Getachew Gebrehana , Hunduma Legesse Geleta

According to the von Neumann-Halperin and Lapidus theorems, in a Hilbert space the iterates of products or, respectively, of convex combinations of orthoprojections are strongly convergent. We extend these results to the iterates of convex…

Functional Analysis · Mathematics 2018-06-05 Catalin Badea , Yuri I. Lyubich

We prove that a Hilbert space frame $\fti$ contains a Riesz basis if every subfamily $\ftj , J \subseteq I ,$ is a frame for its closed span. Secondly we give a new characterization of Banach spaces which do not have any subspace isomorphic…

Functional Analysis · Mathematics 2008-02-03 Peter G. Casazza , Ole Christensen

Let $E$ be a Banach space and $\X$ be the closed unit ball of the dual space $E^*$. For a compact set $K$ in $E$, we prove that $K$ is polynomially convex in $E$ if and only if there exist a unital commutative Banach algebra $A$ and a…

Functional Analysis · Mathematics 2017-05-19 Mortaza Abtahi , Sara Farhangi

We consider weighted banach spaces of holomorphic functions on the upper half plane that are determined by $ \|f\|=\sup_{y>0,-\infty<x<\infty}p(y)|f(x+iy)|<\infty $ for a very large class of weight functions p. We completely solve the…

Functional Analysis · Mathematics 2007-05-23 Martin A. Stanev

We introduce the $\mathcal{L}^p$ spaces of measurable functions whose $p$-th power is summable with respect to the uniform measure over the Levi-Civita field $\mathcal{R}$. These spaces are the counterparts of the real $L^p$ spaces based…

Functional Analysis · Mathematics 2020-06-15 Emanuele Bottazzi

In our note we show the very close connection between the existence of a Finite Dimensional Decomposition (FDD for short) for a separable Banach space $X$ and the existence of a Lipschitz retraction of $X$ onto a small (in a certain precise…

Functional Analysis · Mathematics 2021-11-23 Petr Hájek , Rubén Medina

We show that if $X$ is a Banach space with a Schauder basis, $\Omega\subset X$ is a pseudoconvex open subset, and $u:\,\Omega\to(-\infty,\infty)$ is a locally bounded function, then there are a Banach space $Z$ and a holomorphic function…

Complex Variables · Mathematics 2010-10-20 Imre Patyi

In this paper we give a simple proof of inequalities of integrals of functions which are the composition of nonnegative continous convex functions on a vector space ${\bf R}^m$ and vector-valued functions in a weakly compact subset of a…

Functional Analysis · Mathematics 2007-08-27 Zhenglu Jiang , Xiaoyong Fu , Hongjiong Tian

We analyze smooth nonlinear mappings for Hilbert and Banach spaces that carry small balls to convex sets, provided that the radius of the balls is small enough. Being focused on the study of new and mild sufficient conditions for a…

Functional Analysis · Mathematics 2024-03-18 Yarema A. Prykarpatskyy , Petro Ya. Pukach , Myroslava I. Vovk , Michal Greguš

We give a metric characterisation of when the Lipschitz-free space over a separable ultrametric space is a dual Banach space. In the case where the Lipschitz-free space has a predual, we show that this predual is M-embedded if and only if…

Functional Analysis · Mathematics 2025-10-13 Trond A. Abrahamsen , Vegard Lima , Andre Ostrak

Let $X$ be a Banach space, let $(\Omega,\mu)$ be a $\sigma$-finite measure space and let $A,B\colon\Omega\to B(X)$ be strongly measurable $\gamma$-bounded functions. We show that for all $x\in X$ and all $x^*\in X^*$, there exist a Hilbert…

Functional Analysis · Mathematics 2024-02-19 Christian Le Merdy

We study extension theorems for Lipschitz-type operators acting on metric spaces and with values on spaces of integrable functions. Pointwise domination is not a natural feature of such spaces, and so almost everywhere inequalities and…

Functional Analysis · Mathematics 2019-10-02 W. V. Cavalcante , P. Rueda , E. A. Sánchez-Pérez

Let SB be the standard coding for separable Banach spaces as subspaces of $C(\Delta)$. In these notes, we show that if $\mathbb{B} \subset \text{SB}$ is a Borel subset of spaces with separable dual, then the assignment $X \mapsto X^*$ can…

Functional Analysis · Mathematics 2016-12-23 Bruno de Mendonça Braga

A subset of a convex body $B$ containing the origin in a Euclidean space is {\it parkable in $B$} if it can be translated inside $B$ in such a manner that the translate the origin. We provide characterizations of ellipsoids and of centrally…

Metric Geometry · Mathematics 2016-03-30 Alexandru Chirvasitu

Under the right conditions on a compact metric space $X$ and on a Banach space $E$, we give a description of the $2$-local (standard) isometries on the Banach space $\hbox{Lip}(X,E)$ of vector-valued Lipschitz functions from $X$ to $E$ in…

Functional Analysis · Mathematics 2017-08-10 Antonio Jiménez-Vargas , Lei Li , Antonio M. Peralta , Liguang Wang , Ya-Shu Wang

Let us consider a Banach space $X$ with the property that every real-valued Lipschitz function $f$ can be uniformly approximated by a Lipschitz, $C^1$-smooth function $g$ with $\Lip(g)\le C \Lip(f)$ (with $C$ depending only on the space…

Functional Analysis · Mathematics 2011-01-17 Mar Jimenez-Sevilla , Luis Sanchez-Gonzalez

Let $A$ be a complex Banach space with a norm $\|f\|=\|f\|_X+\|d(f)\|_Y$ for $f\in A$, where $d$ is a complex linear map from $A$ onto a Banach space $B$, and $\|\cdot\|_K$ represents the supremum norm on a compact Hausdorff space $K$. In…

Functional Analysis · Mathematics 2025-03-10 M. G. Cabrera-Padilla , A. Jiménez-Vargas , Takeshi Miura , Moisés Villegas-Vallecillos