The Fixed Point Property in c0 with an Equivalent Norm

We study the fixed point property (FPP) in the Banach space c0 with the equivalent norm ‖⋅‖D. The space c0 with this norm has the weak fixed point property. We prove that every infinite-dimensional subspace of (c0,‖⋅‖D) contains a complemented asymptotically isometric copy of c0, and thus does not h...

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Main Authors: Berta Gamboa de Buen, Fernando Núñez-Medina
Format: Article
Language:English
Published: Wiley 2011-01-01
Series:Abstract and Applied Analysis
Online Access:http://dx.doi.org/10.1155/2011/574614
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author Berta Gamboa de Buen
Fernando Núñez-Medina
author_facet Berta Gamboa de Buen
Fernando Núñez-Medina
author_sort Berta Gamboa de Buen
collection DOAJ
description We study the fixed point property (FPP) in the Banach space c0 with the equivalent norm ‖⋅‖D. The space c0 with this norm has the weak fixed point property. We prove that every infinite-dimensional subspace of (c0,‖⋅‖D) contains a complemented asymptotically isometric copy of c0, and thus does not have the FPP, but there exist nonempty closed convex and bounded subsets of (c0,‖⋅‖D) which are not ω-compact and do not contain asymptotically isometric c0—summing basis sequences. Then we define a family of sequences which are asymptotically isometric to different bases equivalent to the summing basis in the space (c0,‖⋅‖D), and we give some of its properties. We also prove that the dual space of (c0,‖⋅‖D) over the reals is the Bynum space l1∞ and that every infinite-dimensional subspace of l1∞ does not have the fixed point property.
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spelling doaj-art-bb7c97c85b294f9f83df9585512162802025-02-03T01:27:48ZengWileyAbstract and Applied Analysis1085-33751687-04092011-01-01201110.1155/2011/574614574614The Fixed Point Property in c0 with an Equivalent NormBerta Gamboa de Buen0Fernando Núñez-Medina1Matemáticas Básicas, Centro de Investigación en Matemáticas (CIMAT), Apartado Postal 402, 36000 Guanajuato, GTO, MexicoDepartamento de Matemáticas Aplicadas, Universidad del Papaloapan (UNPA), 68400 Loma Bonita, OAX, MexicoWe study the fixed point property (FPP) in the Banach space c0 with the equivalent norm ‖⋅‖D. The space c0 with this norm has the weak fixed point property. We prove that every infinite-dimensional subspace of (c0,‖⋅‖D) contains a complemented asymptotically isometric copy of c0, and thus does not have the FPP, but there exist nonempty closed convex and bounded subsets of (c0,‖⋅‖D) which are not ω-compact and do not contain asymptotically isometric c0—summing basis sequences. Then we define a family of sequences which are asymptotically isometric to different bases equivalent to the summing basis in the space (c0,‖⋅‖D), and we give some of its properties. We also prove that the dual space of (c0,‖⋅‖D) over the reals is the Bynum space l1∞ and that every infinite-dimensional subspace of l1∞ does not have the fixed point property.http://dx.doi.org/10.1155/2011/574614
spellingShingle Berta Gamboa de Buen
Fernando Núñez-Medina
The Fixed Point Property in c0 with an Equivalent Norm
Abstract and Applied Analysis
title The Fixed Point Property in c0 with an Equivalent Norm
title_full The Fixed Point Property in c0 with an Equivalent Norm
title_fullStr The Fixed Point Property in c0 with an Equivalent Norm
title_full_unstemmed The Fixed Point Property in c0 with an Equivalent Norm
title_short The Fixed Point Property in c0 with an Equivalent Norm
title_sort fixed point property in c0 with an equivalent norm
url http://dx.doi.org/10.1155/2011/574614
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