Proper 1-ball contractive retractions in Banach spaces of measurable functions
2005 ◽
Vol 72
(2)
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pp. 299-315
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Keyword(s):
In this paper we consider the Wośko problem of evaluating, in an infinite-dimensional Banach space X, the infimum of all k ≤ 1 for which there exists a k-ball contractive retraction of the unit ball onto its boundary. We prove that in some classical Banach spaces the best possible value 1 is attained. Moreover we give estimates of the lower H-measure of noncompactness of the retractions we construct.
2001 ◽
Vol 33
(4)
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pp. 443-453
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1988 ◽
Vol 103
(3)
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pp. 497-502
2011 ◽
Vol 53
(3)
◽
pp. 443-449
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2020 ◽
Vol 74
(1)
◽
pp. 45