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We consider the structure of divergence-free vector measures on the plane. We show that such measures can be decomposed into measures induced by closed simple curves. More generally, we show that if the divergence of a planar vector-valued…

Analysis of PDEs · Mathematics 2020-11-25 Paolo Bonicatto , Nikolay A. Gusev

We show that every infinite dimensional Banach space has a closed and bounded convex set that is not remotal.

Functional Analysis · Mathematics 2010-01-29 Miguel Martin , T. S. S. R. K. Rao

In the paper we study closures of classes of log--concave measures under taking weak limits, linear transformations and tensor products. We consider what uniform measures on convex bodies can one obtain starting from some class…

Functional Analysis · Mathematics 2009-10-21 Jakub Onufry Wojtaszczyk

We construct a purely unrectifiable set of finite $\mathcal H^1$-measure in every infinite dimensional separable Banach space $X$ whose image under every $0\neq x^*\in X^*$ has positive Lebesgue measure. This demonstrates completely the…

Functional Analysis · Mathematics 2018-09-18 David Bate , Marianna Csörnyei , Bobby Wilson

Fixed point theory studies conditions under which nonexpansive maps on Banach spaces have fixed points. This paper examines the open question of whether every reflexive Banach space has the fixed point property. After surveying classical…

Functional Analysis · Mathematics 2025-09-17 Faruk Alpay , Hamdi Alakkad

The optimum subspace decomposition of the infinite-dimensional compressible random processes in the locally convex Hausdorff space has been propose and its dimension has been measured. We conduct topological analysis of finite- and…

Information Theory · Computer Science 2022-08-30 Mohammadreza Robaei , Robert Akl

In a previous paper the second author introduced a compact topology on the space of closed ideals of a unital Banach algebra A. If A is separable then this topology is either metrizable or else neither Hausdorff nor first countable. Here it…

Functional Analysis · Mathematics 2007-05-23 J. F. Feinstein , D. W. B. Somerset

the main goal of this paper is to prove that any Banach space X, that every dual ball in X** is weak* -separable, or every weak* -closed convex subset in X** is weak* -separable, or every norm-closed convex set in X* is constructible,…

Functional Analysis · Mathematics 2009-01-31 Hadi Haghshenas

A separable metric space X is an H-null set if any uniformly continuous image of X has Hausdorff dimension zero. upper H-null, directed P-null and P-null sets are defined likewise, with other fractal dimensions in place of Hausdorff…

Logic · Mathematics 2012-08-29 Ondrej Zindulka

Shimizu and Takahashi have shown that every decreasing sequence of nonempty, bounded, closed, convex subsets of a complete, uniformly Takahashi convex metric space has nonempty intersection. It is well known that the Menger convexity is a…

General Topology · Mathematics 2024-08-13 Ajit Kumar Gupta , Saikat Mukherjee

We show that whenever a separable subset $S$ of a complete metric space $X$ admits a $d$-dimensional weak tangent field, the set $S$ is close to being $d$-dimensional in the following sense. Whenever $\mu$ is a Borel finite measure on $X$…

Metric Geometry · Mathematics 2026-04-20 Jakub Takáč

The notion of super weak compactness for subsets of Banach spaces is a strengthening of the weak compactness that can be described as a local version of super-reflexivity. A recent result of K. Tu which establishes that the closed convex…

Functional Analysis · Mathematics 2021-07-13 Gilles Lancien , Matias Raja

Let $G$ be an abelian Polish group, e.g. a separable Banach space. A subset $X \subset G$ is called Haar null (in the sense of Christensen) if there exists a Borel set $B \supset X$ and a Borel probability measure $\mu$ on $G$ such that…

Logic · Mathematics 2016-01-07 Márton Elekes , Zoltán Vidnyánszky

In this paper we study set convergence aspects for Banach spaces of vector-valued measures with divergences (represented by measures or by functions) and applications. We consider a form of normal trace characterization to establish…

Optimization and Control · Mathematics 2023-06-28 Nicholas Chisholm , Carlos N. Rautenberg

A generalization of the Lebesgue number lemma is obtained. It is proved that, if each countably infinite locally finite open cover of a chainable metric space $X$ has a Lebesgue number, then $X$ is totally bounded. A property of metric…

General Topology · Mathematics 2022-05-25 Ajit Kumar Gupta , Saikat Mukherjee

A sequence $\{f_n\}$ of strongly-measurable functions taking values in a Banach space $\X$ is scalarly null a\.e\. (resp. scalarly null in measure) if $x^*f_n \rightarrow0$ a\.e\. (resp. $x^*f_n \rightarrow 0$ in measure) for every $x^*\in…

Functional Analysis · Mathematics 2016-09-06 Stephen J. Dilworth , Maria Girardi

We prove that a closed convex subset $C$ of a complete linear metric space $X$ is polyhedral in its closed linear hull if and only if no infinite subset $A\subset X\backslash C$ can be hidden behind $C$ in the sense $[x,y]\cap C\not =…

Functional Analysis · Mathematics 2011-11-22 Taras Banakh , Ivan Hetman

We prove that in a Euclidean space of dimension at least two, there exists a compact set of Lebesgue measure zero such that any real-valued Lipschitz function defined on the space is differentiable at some point in the set. Such a set is…

Functional Analysis · Mathematics 2011-05-17 Michael Doré , Olga Maleva

A Banach space has the weak fixed point property if its dual space has a weak$^*$ sequentially compact unit ball and the dual space satisfies the weak$^*$ uniform Kadec-Klee property; and it has the \fpp if there exists $\epsilon>0$ such…

Functional Analysis · Mathematics 2008-04-04 P. N. Dowling , B. Randrianantoanina , B. Turett

For A a separable unital C*-algebra and M a separable McDuff II_1-factor, we show that the space Hom_w(A,M) of weak approximate unitary equivalence classes of unital *-homomorphisms A \rightarrow M may be considered as a closed, bounded,…

Operator Algebras · Mathematics 2015-12-02 Scott Atkinson