Strongly Extreme Points and Approximation Properties
Canadian mathematical bulletin, Tome 61 (2018) no. 3, pp. 449-457
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We show that if $x$ is a strongly extreme point of a bounded closed convex subset of a Banach space and the identity has a geometrically and topologically good enough local approximation at $x$ , then $x$ is already a denting point. It turns out that such an approximation of the identity exists at any strongly extreme point of the unit ball of a Banach space with the unconditional compact approximation property. We also prove that every Banach space with a Schauder basis can be equivalently renormed to satisfy the suõcient conditions mentioned.
Mots-clés :
46B20, 46B04, denting point, strongly extreme point, unconditional compact approximation property
Abrahamsen, Trond A.; Hájek, Petr; Nygaard, Olav; Troyanski, Stanimir L. Strongly Extreme Points and Approximation Properties. Canadian mathematical bulletin, Tome 61 (2018) no. 3, pp. 449-457. doi: 10.4153/CMB-2017-067-3
@article{10_4153_CMB_2017_067_3,
author = {Abrahamsen, Trond A. and H\'ajek, Petr and Nygaard, Olav and Troyanski, Stanimir L.},
title = {Strongly {Extreme} {Points} and {Approximation} {Properties}},
journal = {Canadian mathematical bulletin},
pages = {449--457},
year = {2018},
volume = {61},
number = {3},
doi = {10.4153/CMB-2017-067-3},
url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-2017-067-3/}
}
TY - JOUR AU - Abrahamsen, Trond A. AU - Hájek, Petr AU - Nygaard, Olav AU - Troyanski, Stanimir L. TI - Strongly Extreme Points and Approximation Properties JO - Canadian mathematical bulletin PY - 2018 SP - 449 EP - 457 VL - 61 IS - 3 UR - http://geodesic.mathdoc.fr/articles/10.4153/CMB-2017-067-3/ DO - 10.4153/CMB-2017-067-3 ID - 10_4153_CMB_2017_067_3 ER -
%0 Journal Article %A Abrahamsen, Trond A. %A Hájek, Petr %A Nygaard, Olav %A Troyanski, Stanimir L. %T Strongly Extreme Points and Approximation Properties %J Canadian mathematical bulletin %D 2018 %P 449-457 %V 61 %N 3 %U http://geodesic.mathdoc.fr/articles/10.4153/CMB-2017-067-3/ %R 10.4153/CMB-2017-067-3 %F 10_4153_CMB_2017_067_3
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