The property WORTH\(^\ast\) and the weak fixed point property (Q2925031)
From MaRDI portal
| This is the item page for this Wikibase entity, intended for internal use and editing purposes. Please use this page instead for the normal view: The property WORTH\(^\ast\) and the weak fixed point property |
scientific article; zbMATH DE number 6359055
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | The property WORTH\(^\ast\) and the weak fixed point property |
scientific article; zbMATH DE number 6359055 |
Statements
20 October 2014
0 references
fixed point property
0 references
nonexpansive mapping
0 references
property WORTH
0 references
property WORTH*
0 references
1-unconditional basis
0 references
The property WORTH\(^\ast\) and the weak fixed point property (English)
0 references
A Banach space \(X\) is said to have the weak fixed point property if every nonexpansive mapping \(T:C\rightarrow C\) acting on a weakly compact convex subset \(C\) of \(X\) has a fixed point. A Banach space \(X\) has the property WORTH\(^{\ast }\) if, for every weak\(^{\ast }\) null sequence \((x_{n}^{\ast })\) and every \(x^{\ast }\in X^{\ast }\), NEWLINE\[NEWLINE\limsup_{n}\left\| x_{n}^{\ast }-x^{\ast }\right\| =\limsup_{n}\left\| x_{n}^{\ast }+x^{\ast }\right\| . NEWLINE\]NEWLINE It is shown that if the Banach-Mazur distance \(d(X,Y)<\frac{\sqrt{33}-3}{2}\) and \(Y^{\ast }\) has the WORTH\(^{\ast }\) property, then \(X\) has the weak fixed point property. In particular, WORTH\(^{\ast }\) implies the weak fixed point property which is a slight extension of the recent result of \textit{H. Fetter} and \textit{B. G. De Buen} [Fixed Point Theory Appl. 2010, Article ID 342691, 7 p. (2010; Zbl 1217.46011)].
0 references