Results 71 to 80 of about 75,695 (101)

Extreme points in polyhedral Banach spaces

Israel Journal of Mathematics, 2017
Polyhedral Banach spaces were introduced by \textit{V. Klee} at the end of the paper [Acta Math. 103, 243--267 (1960; Zbl 0148.16203)] in 1960 as those real spaces where the unit balls of all subspaces are polygons. \(c_0\) serves as the basic example of such a space, and Klee proved in the last theorem of that paper the non-trivial fact that \(c_0 ...
C. D. Bernardi
semanticscholar   +8 more sources

Polyhedral banach spaces and extensions of compact operators

Israel Journal of Mathematics, 1969
LetX be a polyhedral Banach space whose dual is anL 1(μ) space for some measureμ. Then for each Banach spacesY ⊆Z and each compact operatorT: Y →X there exists a norm preserving compact extension $$\tilde T:Z \to X$$ Z →X.
A. Lazar
semanticscholar   +5 more sources

Three characterizations of polyhedral Banach spaces

Ukrainian Mathematical Journal, 1990
An infinite-dimensional Banach space E is called polyhedral, if intersections of all finite dimensional spaces with the unit ball are polyhedra. Three characterizations, up to isomorphism, of such spaces are given. A ``local'' characterization uses a normed set in the unit dual sphere.
V. Fonf
semanticscholar   +5 more sources

Analytic and polyhedral approximation of convex bodies in separable polyhedral Banach spaces

Israel Journal of Mathematics, 1998
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
R. Deville, V. Fonf, P. Hájek
semanticscholar   +5 more sources

The wigner property for CL-spaces and finite-dimensional polyhedral banach spaces

Proceedings of the Edinburgh Mathematical Society, 2021
We say that a map $f$ from a Banach space $X$ to another Banach space $Y$ is a phase-isometry if the equality \[ \{\|f(x)+f(y)\|, \|f(x)-f(y)\|\}=\{\|x+y\|, \|x-y\|\} \]holds for all $x,\,y\in X$. A Banach space $X$ is said to have the Wigner property if
D. Tan, Xujian Huang
semanticscholar   +6 more sources

Massiveness of the set of extreme points of the dual ball of a Banach space. Polyhedral spaces

Functional Analysis and Its Applications, 1978
V. P. Fond
semanticscholar   +4 more sources

Proximinality Properties in Lp(μ, X) and Polyhedral Direct Sums of Banach Spaces

Numerical Functional Analysis and Optimization, 2014
For a closed subspace Y of a Banach space X, we define a separably determined property for Y in X. We prove that if the strong -ball property is separably determined for Y in X, then L 1(μ, Y) has the strong -ball property in L 1(μ, X). For an M-embedded space X, we give a class of elements in L 1(μ, X **) having best approximations from L 1(μ, X).
C. R. Jayanarayanan
semanticscholar   +2 more sources

An algorithm for the best approximation by elements of a polyhedral set in Banach spaces

Numerical Functional Analysis and Optimization, 1983
The purpose of this paper is to give an algorithm for finding the best approximation by elements of a polyhedral set of a reflexive and strictly convex Banach space. A dual problem is defined whose solutions can be used to find the solution of the initial one.
C. Zălinescu
semanticscholar   +2 more sources

Smallness and the Covering of a Banach Space

Milan Journal of Mathematics, 2012
J. Castillo, P. Papini
semanticscholar   +4 more sources

On isosceles orthogonality and some geometric constants in a normed space

Aequationes Mathematicae, 2022
We study the James constant $$J({\mathbb {X}})$$ J ( X ) , an important geometric quantity associated with a normed space $$ {\mathbb {X}} $$ X , and explore its connection with isosceles orthogonality $$ \perp _I. $$ ⊥ I .
D. Sain, Souvik Ghosh, K. Paul
semanticscholar   +1 more source