A non-archimedean Dugundji extension theorem
Czechoslovak Mathematical Journal, Tome 63 (2013) no. 1, pp. 157-164
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We prove a non-archimedean Dugundji extension theorem for the spaces $C^{\ast }(X,\mathbb {K})$ of continuous bounded functions on an ultranormal space $X$ with values in a non-archimedean non-trivially valued complete field $\mathbb {K}$. Assuming that $\mathbb {K}$ is discretely valued and $Y$ is a closed subspace of $X$ we show that there exists an isometric linear extender $T\colon C^{\ast }(Y,\mathbb {K})\rightarrow C^{\ast }(X,\mathbb {K})$ if $X$ is collectionwise normal or $Y$ is Lindelöf or $\mathbb {K}$ is separable. We provide also a self contained proof of the known fact that any metrizable compact subspace $Y$ of an ultraregular space $X$ is a retract of $X$.
We prove a non-archimedean Dugundji extension theorem for the spaces $C^{\ast }(X,\mathbb {K})$ of continuous bounded functions on an ultranormal space $X$ with values in a non-archimedean non-trivially valued complete field $\mathbb {K}$. Assuming that $\mathbb {K}$ is discretely valued and $Y$ is a closed subspace of $X$ we show that there exists an isometric linear extender $T\colon C^{\ast }(Y,\mathbb {K})\rightarrow C^{\ast }(X,\mathbb {K})$ if $X$ is collectionwise normal or $Y$ is Lindelöf or $\mathbb {K}$ is separable. We provide also a self contained proof of the known fact that any metrizable compact subspace $Y$ of an ultraregular space $X$ is a retract of $X$.
DOI :
10.1007/s10587-013-0010-8
Classification :
46S10, 54C35
Keywords: Dugundji extension theorem; non-archimedean space; space of continuous functions; 0-dimensional space
Keywords: Dugundji extension theorem; non-archimedean space; space of continuous functions; 0-dimensional space
@article{10_1007_s10587_013_0010_8,
author = {K\k{a}kol, Jerzy and Kubzdela, Albert and \'Sliwa, Wies{\l}aw},
title = {A non-archimedean {Dugundji} extension theorem},
journal = {Czechoslovak Mathematical Journal},
pages = {157--164},
year = {2013},
volume = {63},
number = {1},
doi = {10.1007/s10587-013-0010-8},
mrnumber = {3035503},
zbl = {1274.46131},
language = {en},
url = {http://geodesic.mathdoc.fr/articles/10.1007/s10587-013-0010-8/}
}
TY - JOUR AU - Kąkol, Jerzy AU - Kubzdela, Albert AU - Śliwa, Wiesław TI - A non-archimedean Dugundji extension theorem JO - Czechoslovak Mathematical Journal PY - 2013 SP - 157 EP - 164 VL - 63 IS - 1 UR - http://geodesic.mathdoc.fr/articles/10.1007/s10587-013-0010-8/ DO - 10.1007/s10587-013-0010-8 LA - en ID - 10_1007_s10587_013_0010_8 ER -
%0 Journal Article %A Kąkol, Jerzy %A Kubzdela, Albert %A Śliwa, Wiesław %T A non-archimedean Dugundji extension theorem %J Czechoslovak Mathematical Journal %D 2013 %P 157-164 %V 63 %N 1 %U http://geodesic.mathdoc.fr/articles/10.1007/s10587-013-0010-8/ %R 10.1007/s10587-013-0010-8 %G en %F 10_1007_s10587_013_0010_8
Kąkol, Jerzy; Kubzdela, Albert; Śliwa, Wiesław. A non-archimedean Dugundji extension theorem. Czechoslovak Mathematical Journal, Tome 63 (2013) no. 1, pp. 157-164. doi: 10.1007/s10587-013-0010-8
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