Proximinality in geodesic spaces

Let X be a complete CAT(0) space with the geodesic extension property and Alexandrov curvature bounded below. It is shown that if C is a closed subset of X, then the set of points of X which have a unique nearest point in C is Gδ and of the second Baire category in X. If, in addition, C is bounded,...

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Main Authors: A. Kaewcharoen, W. A. Kirk
Format: Article
Language:English
Published: Wiley 2006-01-01
Series:Abstract and Applied Analysis
Online Access:http://dx.doi.org/10.1155/AAA/2006/43591
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author A. Kaewcharoen
W. A. Kirk
author_facet A. Kaewcharoen
W. A. Kirk
author_sort A. Kaewcharoen
collection DOAJ
description Let X be a complete CAT(0) space with the geodesic extension property and Alexandrov curvature bounded below. It is shown that if C is a closed subset of X, then the set of points of X which have a unique nearest point in C is Gδ and of the second Baire category in X. If, in addition, C is bounded, then the set of points of X which have a unique farthest point in C is dense in X. A proximity result for set-valued mappings is also included.
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spelling doaj-art-ceab08b77e3040f39b65f32564fb14192025-02-03T05:58:37ZengWileyAbstract and Applied Analysis1085-33751687-04092006-01-01200610.1155/AAA/2006/4359143591Proximinality in geodesic spacesA. Kaewcharoen0W. A. Kirk1Department of Mathematics, Faculty of Science, Naresuan University, Phitsanulok 65000, ThailandDepartment of Mathematics, University of Iowa, Iowa City, IA 52242-1419, USALet X be a complete CAT(0) space with the geodesic extension property and Alexandrov curvature bounded below. It is shown that if C is a closed subset of X, then the set of points of X which have a unique nearest point in C is Gδ and of the second Baire category in X. If, in addition, C is bounded, then the set of points of X which have a unique farthest point in C is dense in X. A proximity result for set-valued mappings is also included.http://dx.doi.org/10.1155/AAA/2006/43591
spellingShingle A. Kaewcharoen
W. A. Kirk
Proximinality in geodesic spaces
Abstract and Applied Analysis
title Proximinality in geodesic spaces
title_full Proximinality in geodesic spaces
title_fullStr Proximinality in geodesic spaces
title_full_unstemmed Proximinality in geodesic spaces
title_short Proximinality in geodesic spaces
title_sort proximinality in geodesic spaces
url http://dx.doi.org/10.1155/AAA/2006/43591
work_keys_str_mv AT akaewcharoen proximinalityingeodesicspaces
AT wakirk proximinalityingeodesicspaces