Compactness and countable compactness in weak topologies
Studia Mathematica, Tome 112 (1994) no. 3, pp. 243-250
Voir la notice de l'article provenant de la source Institute of Mathematics Polish Academy of Sciences
A bounded closed convex set K in a Banach space X is said to have quasi-normal structure if each bounded closed convex subset H of K for which diam(H) > 0 contains a point u for which ∥u-x∥ diam(H) for each x ∈ H. It is shown that if the convex sets on the unit sphere in X satisfy this condition (which is much weaker than the assumption that convex sets on the unit sphere are separable), then relative to various weak topologies, the unit ball in X is compact whenever it is countably compact.
Keywords:
weak topologies, compactness, countable compactness, quasi-normal structure, convexity structures
Affiliations des auteurs :
W. A. Kirk 1
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author = {W. A. Kirk},
title = {Compactness and countable compactness in weak topologies},
journal = {Studia Mathematica},
pages = {243--250},
publisher = {mathdoc},
volume = {112},
number = {3},
year = {1994},
doi = {10.4064/sm-112-3-243-250},
language = {en},
url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-112-3-243-250/}
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TY - JOUR AU - W. A. Kirk TI - Compactness and countable compactness in weak topologies JO - Studia Mathematica PY - 1994 SP - 243 EP - 250 VL - 112 IS - 3 PB - mathdoc UR - http://geodesic.mathdoc.fr/articles/10.4064/sm-112-3-243-250/ DO - 10.4064/sm-112-3-243-250 LA - en ID - 10_4064_sm_112_3_243_250 ER -
W. A. Kirk. Compactness and countable compactness in weak topologies. Studia Mathematica, Tome 112 (1994) no. 3, pp. 243-250. doi: 10.4064/sm-112-3-243-250
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