Proximinal subspaces of A(K) of finite codimension

We study an analogue of Garkavi's result on proximinal subspaces of C(X) of finite codimension in the context of the space A(K) of affine continuous functions on a compact convex set K. We give an example to show that a simple-minded analogue of Garkavi's result fails for these spaces. Whe...

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Main Author: T. S. S. R. K. Rao
Format: Article
Language:English
Published: Wiley 2003-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Online Access:http://dx.doi.org/10.1155/S0161171203212308
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author T. S. S. R. K. Rao
author_facet T. S. S. R. K. Rao
author_sort T. S. S. R. K. Rao
collection DOAJ
description We study an analogue of Garkavi's result on proximinal subspaces of C(X) of finite codimension in the context of the space A(K) of affine continuous functions on a compact convex set K. We give an example to show that a simple-minded analogue of Garkavi's result fails for these spaces. When K is a metrizable Choquet simplex, we give a necessary and sufficient condition for a boundary measure to attain its norm on A(K). We also exhibit proximinal subspaces of finite codimension of A(K) when the measures are supported on a compact subset of the extreme boundary.
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spelling doaj-art-30b693aa7ada4707af8aaa6d8eb467a32025-02-03T01:12:15ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04252003-01-012003392501250510.1155/S0161171203212308Proximinal subspaces of A(K) of finite codimensionT. S. S. R. K. Rao0Statistics and Mathematics Unit, Indian Statistical Institute, RV College Post Office, Bangalore 560 059, IndiaWe study an analogue of Garkavi's result on proximinal subspaces of C(X) of finite codimension in the context of the space A(K) of affine continuous functions on a compact convex set K. We give an example to show that a simple-minded analogue of Garkavi's result fails for these spaces. When K is a metrizable Choquet simplex, we give a necessary and sufficient condition for a boundary measure to attain its norm on A(K). We also exhibit proximinal subspaces of finite codimension of A(K) when the measures are supported on a compact subset of the extreme boundary.http://dx.doi.org/10.1155/S0161171203212308
spellingShingle T. S. S. R. K. Rao
Proximinal subspaces of A(K) of finite codimension
International Journal of Mathematics and Mathematical Sciences
title Proximinal subspaces of A(K) of finite codimension
title_full Proximinal subspaces of A(K) of finite codimension
title_fullStr Proximinal subspaces of A(K) of finite codimension
title_full_unstemmed Proximinal subspaces of A(K) of finite codimension
title_short Proximinal subspaces of A(K) of finite codimension
title_sort proximinal subspaces of a k of finite codimension
url http://dx.doi.org/10.1155/S0161171203212308
work_keys_str_mv AT tssrkrao proximinalsubspacesofakoffinitecodimension