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On the Chebyshev Center and the Nonemptiness of the Intersection of Nested Sets
G. Z. Chelidzeab, A. N. Daneliac, M. Z. Suladzec a Kutaisi International University
b Muskhelishvili Institute of Computational Mathematics
c Tbilisi Ivane Javakhishvili State University
Abstract:
We show that if every bounded set in a Banach space has a Chebyshev center, then the intersection of nested closed bounded sets in this space is nonempty in the case of a critical parameter value. This result generalizes previously obtained sufficient conditions for the nonemptiness of the intersection in the critical case. We also answer a question posed by G. Z. Chelidze and P. L. Papini for Banach spaces satisfying the Opial condition for the weak-$*$ topology.
Keywords:
numerical parameter of a set in a normed space, nonemptiness of the intersection of nested sets, Chebyshev center, Opial weak-$*$ property.
Received: 02.09.2021 Revised: 11.10.2021
Citation:
G. Z. Chelidze, A. N. Danelia, M. Z. Suladze, “On the Chebyshev Center and the Nonemptiness of the Intersection of Nested Sets”, Mat. Zametki, 111:3 (2022), 451–458; Math. Notes, 111:3 (2022), 478–483
Linking options:
https://www.mathnet.ru/eng/mzm13279https://doi.org/10.4213/mzm13279 https://www.mathnet.ru/eng/mzm/v111/i3/p451
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