Reflexivity is equivalent to stability of the almost fixed point property

In this work we show that the family of closed convex sets with the almost fixed point property is not stable under renormings for non-reflexive Banach spaces. This, together with a result by Reich, shows that a Banach space is reflexive if and only if it has the same family of closed convex sets wi...

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Bibliographic Details
Authors: Fetter Nathansky, Helga Andrea, Japón Pineda, María de los Ángeles, Villada Bedoya, J.
Format: article
Status:Published version
Publication Date:2017
Country:España
Institution:Universidad de Sevilla (US)
Repository:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/182208
Online Access:https://hdl.handle.net/11441/182208
https://doi.org/10.1016/j.jmaa.2017.11.007
Access Level:Open access
Keyword:Reflexive Banach spaces
Equivalent norms
Nonexpansive mappings
Almost fixed point property AFPP
Stability
Directionally bounded sets
Description
Summary:In this work we show that the family of closed convex sets with the almost fixed point property is not stable under renormings for non-reflexive Banach spaces. This, together with a result by Reich, shows that a Banach space is reflexive if and only if it has the same family of closed convex sets with the almost fixed point property for every equivalent norm.