Banach spaces not antiproximinal in their second dual (Q807899)
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: Banach spaces not antiproximinal in their second dual |
scientific article; zbMATH DE number 4208757
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Banach spaces not antiproximinal in their second dual |
scientific article; zbMATH DE number 4208757 |
Statements
Banach spaces not antiproximinal in their second dual (English)
0 references
1991
0 references
A subspace M of a Banach space X is said to be antiproximinal in X if the only vectors in X which have closest proximinants from M are elements of M. In [\textit{K. R. Davidson}, J. Approximation Theory 47, 203-213 (1986; Zbl 0595.41034)], the author claims that if a Banach space X has the projection approximation property, then X has an equivalent norm \(| \cdot |\) under which it is antiproximinal in \(X^{**}\). The authors point out a gap in Davidson's argument and show that, in fact, \((\ell_ 1,| \cdot |)\) is not antiproximinal in its second dual.
0 references
proximal subspaces
0 references
projection approximation
0 references
antiproximinal
0 references
0.9166155
0 references
0 references
0 references
0.86946636
0 references
0.86942434
0 references