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Related papers: Strong pseudoconvexity in Banach spaces

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The spatial distribution has been widely used to develop various nonparametric procedures for finite dimensional multivariate data. In this paper, we investigate the concept of spatial distribution for data in infinite dimensional Banach…

Methodology · Statistics 2014-07-04 Anirvan Chakraborty , Probal Chaudhuri

Given a Banach space $\mathcal X$, let $x$ be a point in $\text{ball}(\mathcal X)$, the closed unit ball of $\mathcal X$. One says that $x$ is a strongly extreme point of $\text{ball}(\mathcal X)$ if it has the following property: for every…

Functional Analysis · Mathematics 2026-04-01 Konstantin M. Dyakonov

The standard theory of Banach spaces is built upon the notions of vector space, triangle inequality and Cauchy completeness. Here we propose a `hyperbolic' variant of this `elliptic' framework where general linear combinations are replaced…

Functional Analysis · Mathematics 2025-12-11 Nicola Gigli

We introduce and study Banach spaces which have property CWO, i.e., every finite convex combination of relatively weakly open subsets of their unit ball is open in the relative weak topology of the unit ball. Stability results of such…

Functional Analysis · Mathematics 2018-06-29 Trond Arnold Abrahamsen , Julio Becerra Guerrero , Rainis Haller , Vegard Lima , Märt Põldvere

The essence of the notion of lineability and spaceability is to find linear structures in somewhat chaotic environments. The existing methods, in general, use \textit{ad hoc} arguments and few general techniques are known. Motivated by the…

Functional Analysis · Mathematics 2015-10-01 Tony K. Nogueira , Daniel Pellegrino

Based on the recently introduced uniform $\lambda-$adjustment for closed subspaces of Banach spaces we extend the concept of the strictly singular and finitely strictly singular operators to the sequences of closed subspaces and operators…

Functional Analysis · Mathematics 2009-02-19 Boris Burshteyn

Quasi-invariant and pseudo-differentiable measures on a Banach space $X$ over a non-Archimedean locally compact infinite field with a non-trivial valuation are defined and constructed. Measures are considered with values in non-Archimedean…

General Mathematics · Mathematics 2007-05-23 Sergey V. Ludkovsky

Given a pseudoconvex domain U with C^1-boundary in P^n, n>2, we show that if H^{2n-2}_\dR}(U)\not=0, then there is a strictly psh function in a neighborhood of boundary U. We also solve the \dbar-equation in X=P^n\ U, for data smooth (0,1)…

Complex Variables · Mathematics 2020-09-02 Nessim Sibony

It is known that a Banach space has the strong diameter 2 property (i.e. every convex combination of slices of the unit ball has diameter 2) if and only if the norm on its dual space is octahedral (a notion introduced by Godefroy and…

Functional Analysis · Mathematics 2013-11-12 Rainis Haller , Johann Langemets , Märt Põldvere

For a Banach space $X$ by $Conv_H(X)$ we denote the space of non-empty closed convex subsets of $X$, endowed with the Hausdorff metric. We prove that for any closed convex set $C\subset X$ and its metric component $H_C=\{A\in…

Functional Analysis · Mathematics 2012-12-19 Taras Banakh , Ivan Hetman

This paper is devoted to providing a unifying approach to the study of the uniqueness of unconditional bases, up to equivalence and permutation, of infinite direct sums of quasi-Banach spaces. Our new approach to this type of problem…

Functional Analysis · Mathematics 2021-02-08 Fernando Albiac , Jose L. Ansorena

We prove that every separable Banach space containing $\ell_1$ can be equivalently renormed so that its bidual space is octahedral, which answers, in the separable case, a question by Godefroy in 1989. As a direct consequence, we obtain…

Functional Analysis · Mathematics 2021-07-01 Johann Langemets , Ginés López-Pérez

In this note, we provide a characterization for the set of extreme points of the Lipschitz unit ball in a specific vectorial setting. While the analysis of the case of real-valued functions is covered extensively in the literature, no…

Functional Analysis · Mathematics 2025-10-24 Kristian Bredies , Jonathan Chirinos Rodriguez , Emanuele Naldi

Comparison and localization results for the Lempert function, the Carath\'eodory distance and their infinitesimal forms on strongly pseudoconvex domains are obtained. Related results for visible and strongly complete domains are proved.

Complex Variables · Mathematics 2023-11-28 Nikolai Nikolov

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

In this article, we introduce special domains and discuss the geometry of these domains, which includes showing that every pseudoconvex truncated tube domain is a special domain. Next, we prove a theorem for the envelope of special domains…

Complex Variables · Mathematics 2025-11-10 Suprokash Hazra

We characterize $k-$smoothness of bounded linear operators defined between infinite-dimensional Hilbert spaces. We study the problem in the setting of both finite and infinite-dimensional Banach spaces. We also characterize $k-$smoothness…

Functional Analysis · Mathematics 2024-08-14 Arpita Mal , Subhrajit Sey , Kallol Paul

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

The original motivation for this paper was to provide an efficient quantitative analysis of convex infinite (or semi-infinite) inequality systems whose decision variables run over general infinite-dimensional (resp. finite-dimensional)…

Optimization and Control · Mathematics 2011-02-11 M. J. Cánovas , M. A. LóPez , B. S. Mordukhovich , J. Parra

The notion of adequate function has been recently introduced in order to characterize the essentially strictly functions on a reflexive Banach space among the weakly lower semicontinuous ones. In this paper we reinforce this concept and…

Optimization and Control · Mathematics 2012-03-07 Michel Volle , Constantin Zalinescu