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In this paper we study a class of quasi--variational--hemi\-va\-ria\-tio\-nal inequalities in reflexive Banach spaces. The inequalities contain a convex potential, a locally Lipschitz superpotential, and a solution-dependent set of…

Dynamical Systems · Mathematics 2023-09-12 S. Migorski , JC. Yao , SD. Zeng

We obtain some results for and further examples of subprojective and superprojective Banach spaces. We also give several conditions providing examples of non-reflexive superprojective spaces; one of these conditions is stable under…

Functional Analysis · Mathematics 2016-06-03 Elói M. Galego , Manuel González , Javier Pello

We consider the quasihyperbolic metric, and its generalizations in both the $n$-dimensional Euclidean space $R^n$, and in Banach spaces. Historical background, applications, and our recent work on convexity properties of these metrics are…

Complex Variables · Mathematics 2015-03-19 Riku Klén , Antti Rasila , Jarno Talponen

In this paper, we introduce the notions of $\alpha$-quasicomplemented and totally $\alpha$-quasicomplemented subspaces and we established some results under these contexts. We show, for example, that if $X$ is a separable or reflexive…

Functional Analysis · Mathematics 2024-03-12 A. Barbosa , A. Raposo , G. Ribeiro

The main result: the dual of separable Banach space $X$ contains a total subspace which is not norming over any infinite dimensional subspace of $X$ if and only if $X$ has a nonquasireflexive quotient space with the strictly singular…

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

We establish the first partial regularity results for (strongly) symmetric quasiconvex functionals of linear growth on BD, the space of functions of bounded deformation. By Rindler's foundational work (Lower semicontinuity for integral…

Analysis of PDEs · Mathematics 2020-10-07 Franz Gmeineder

Difficulty in the construction of dual frames for a given Hilbert space led to the introduction of approximately dual frames in Hilbert spaces by Christensen and Laugesen. It becomes even more difficult in Banach spaces to construct duals.…

Functional Analysis · Mathematics 2021-10-20 K. Mahesh Krishna , P. Sam Johnson

This paper provides a self-contained exposition of coorbit spaces associated to integrable group representations and quasi-Banach function spaces, and at the same time extends and simplifies previous work. The main results provide an…

Functional Analysis · Mathematics 2024-02-26 Jordy Timo van Velthoven , Felix Voigtlaender

We prove that if $X$ is a quasi-normed space which possesses an infinite countable dimensional subspace with a separating dual, then it admits a strictly weaker Hausdorff vector topology. Such a topology is constructed explicitly. As an…

Functional Analysis · Mathematics 2014-04-08 Cleon S. Barroso

This paper is devoted to the study of strongly quasinonexpansive mappings in an abstract space and a Banach space.

Functional Analysis · Mathematics 2020-12-29 Koji Aoyama , Kei Zembayashi

Density of Lipschitz functions in Newtonian spaces based on quasi-Banach function lattices is discussed. Newtonian spaces are first-order Sobolev-type spaces on abstract metric measure spaces defined via (weak) upper gradients. Our main…

Functional Analysis · Mathematics 2014-04-29 Lukáš Malý

If $\phi$ is a submeasure satisfying an appropriate lower estimate we give a quantitative result on the total mass of a measure $\mu$ satisfying $0\le\mu\le\phi.$ We give a dual result for supermeasures and then use these results to…

Functional Analysis · Mathematics 2008-02-03 Nigel J. Kalton , Stephen J. Montgomery-Smith

We construct a locally finite graph and a bounded geometry metric space which do not admit a quasi-isometric embedding into any uniformly convex Banach space. Connections with the geometry of $c_0$ and superreflexivity are discussed.

Metric Geometry · Mathematics 2015-01-29 Piotr W. Nowak

Recently introduced by the authors in [Proc. Edinb. Math. Soc. 60 (2020), 139-167], quasi-densities form a large family of real-valued functions partially defined on the power set of the integers that serve as a unifying framework for the…

Number Theory · Mathematics 2022-11-10 Paolo Leonetti , Salvatore Tringali

The paper elucidates the relationship between the density of a Banach space and possible sizes of well-separated subsets of its unit sphere. For example, it is proved that for a large enough space $X$, the unit sphere $S_X$ always contains…

Functional Analysis · Mathematics 2021-01-13 Petr Hájek , Tomasz Kania , Tommaso Russo

In this paper we give some results about the approximation of a Lipschitz function on a Banach space by means of $\Delta$-convex functions. In particular, we prove that the density of $\Delta$-convex functions in the set of Lipschitz…

Functional Analysis · Mathematics 2009-09-25 Manuel Cepedello Boiso

Given a Banach space. We show that its three times dual space can be written as a direct sum. Then being one of the sumands null is a necessary and sufficient condition for the dual space to be reflexive. We end with an application of this…

Functional Analysis · Mathematics 2007-05-23 Javier H. Guachalla

We construct a reflexive Banach space $X$ with a subspace isometric to $X$, which is not complemented in $X$.

Functional Analysis · Mathematics 2023-09-28 Anna Pelczar-Barwacz

We present quasi-Banach spaces which are closely related to the duals of combinatorial Banach spaces. More precisely, for a compact family $\mathcal{F}$ of finite subsets of $\omega$ we define a quasi-norm $\lVert \cdot \rVert^\mathcal{F}$…

Functional Analysis · Mathematics 2025-01-22 Piotr Borodulin-Nadzieja , Sebastian Jachimek , Anna Pelczar-Barwacz

We analyse several examples of separable Banach spaces, some of them new, and relate them to several dichotomies obtained in the previous paper Banach spaces without minimal subspaces, by classifying them according to which side of the…

Functional Analysis · Mathematics 2011-04-26 Valentin Ferenczi , Christian Rosendal