Results 41 to 50 of about 1,404 (80)
EQUIVARIANT GEOMETRY OF BANACH SPACES AND TOPOLOGICAL GROUPS
Forum of Mathematics, Sigma, 2017 We study uniform and coarse embeddings between Banach spaces and topological groups. A particular focus is put on equivariant embeddings, that is, continuous cocycles associated to continuous affine isometric actions of topological groups on separable ...
CHRISTIAN ROSENDAL
doaj +1 more source
An Inequality in Metric Spaces [PDF]
, 2004 In this note we establish a general inequality valid in metric spaces that is related to the polygonal inequality and admits also a natural geometrical interpretation.
Dragomir, Sever S, Goşa, Anca C
core
A really simple elementary proof of the uniform boundedness theorem
, 2010 I give a proof of the uniform boundedness theorem that is elementary (i.e. does not use any version of the Baire category theorem) and also extremely simple.Comment: LaTex2e, 5 pages. Version 2 improves the exposition by isolating the key lemma.
Sokal, Alan D.
core +1 more source
Boundedness and surjectivity in normed spaces
International Journal of Mathematics and Mathematical Sciences, Volume 32, Issue 3, Page 149-165, 2002., 2002 We define the (w* ‐) boundedness property and the (w* ‐) surjectivity property for sets in normed spaces. We show that these properties are pairwise equivalent in complete normed spaces by characterizing them in terms of a category‐like property called (w* ‐) thickness. We give examples of interesting sets having or not having these properties.
Olav Nygaard
wiley +1 more source
A note on nonfragmentability of Banach spaces
International Journal of Mathematics and Mathematical Sciences, Volume 27, Issue 1, Page 39-44, 2001., 2001 We use Kenderov‐Moors characterization of fragmentability to show that if a compact Hausdorff space X with the tree‐completeness property contains a disjoint sequences of clopen sets, then (C(X), weak) is not fragmented by any metric which is stronger than weak topology.
S. Alireza Kamel Mirmostafaee
wiley +1 more source
SPARSE APPROXIMATION AND RECOVERY BY GREEDY ALGORITHMS IN BANACH SPACES
Forum of Mathematics, Sigma, 2014 We study sparse approximation by greedy algorithms. We prove the Lebesgue-type inequalities for the weak Chebyshev greedy algorithm (WCGA), a generalization of the weak orthogonal matching pursuit to the case of a Banach space.
V. N. TEMLYAKOV
doaj +1 more source
Uniform G-Convexity for Vector-Valued Lp Spaces [PDF]
, 2009 2000 Mathematics Subject Classification: 46B20.Uniform G-convexity of Banach spaces is a recently introduced natural generalization of uniform convexity and of complex uniform convexity.
Boyko, Nataliia, Kadets, Vladimir
core
International Journal of Mathematics and Mathematical Sciences, Volume 27, Issue 10, Page 631-639, 2001., 2001 Given an n‐normed space with n ≥ 2, we offer a simple way to derive an (n − 1)‐norm from the n‐norm and realize that any n‐normed space is an (n − 1)‐normed space. We also show that, in certain cases, the (n − 1)‐norm can be derived from the n‐norm in such a way that the convergence and completeness in the n‐norm is equivalent to those in the derived ...
Hendra Gunawan, M. Mashadi
wiley +1 more source
Approximately bisectrix-orthogonality preserving mappings
, 2014 Regarding the geometry of a real normed space ${\mathcal X}$, we mainly introduce a notion of approximate bisectrix-orthogonality on vectors $x, y \in {\mathcal X}$ as follows: $${x\np{\varepsilon}}_W y \mbox{if and only if} \sqrt{2}\frac{1-\varepsilon ...
Zamani, Ali
core +1 more source
KKM and KY fan theorems in modular function spaces
Fixed Point Theory and Applications, 2011 In modular function spaces, we introduce Knaster-Kuratowski-Mazurkiewicz mappings (in short KKM-mappings) and prove an analogue to Ky Fan s fixed point theorem. 2010 Mathematics Subject Classification: Primary 46B20, 47H09; Secondary 47H10.
Latif Abdul +2 more
doaj