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This article is cited in 3 scientific papers (total in 3 papers)
Selections of the best and near-best approximation operators and solarity
A. R. Alimovab a Faculty of Mechanics and Mathematics, Moscow State University, Moscow, 119991 Russia
b Steklov Mathematical Institute of Russian Academy of Sciences, ul. Gubkina 8, Moscow, 119991 Russia
Abstract:
In a finite-dimensional Banach space, a closed set with lower semicontinuous metric projection is shown to have a continuous selection of the near-best approximation operator. Such a set is known to be a sun. In the converse question of the stability of best approximation by suns, it is proved that a strict sun in a finite-dimensional Banach space of dimension at most $3$ is a $P$-sun, has a contractible set of nearest points, and admits a continuous $\varepsilon $-selection from the operator of near-best approximation for any $\varepsilon >0$. A number of approximative and geometric properties of sets with lower semicontinuous metric projection are obtained.
Keywords:
lower semicontinuity of the metric projection, selection of the metric projection, sun, strict sun, near-best approximation.
Received: October 1, 2017
Citation:
A. R. Alimov, “Selections of the best and near-best approximation operators and solarity”, Harmonic analysis, approximation theory, and number theory, Collected papers. Dedicated to Academician Sergei Vladimirovich Konyagin on the occasion of his 60th birthday, Trudy Mat. Inst. Steklova, 303, MAIK Nauka/Interperiodica, Moscow, 2018, 17–25; Proc. Steklov Inst. Math., 303 (2018), 10–17
Linking options:
https://www.mathnet.ru/eng/tm3939https://doi.org/10.1134/S0371968518040027 https://www.mathnet.ru/eng/tm/v303/p17
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Abstract page: | 340 | Full-text PDF : | 38 | References: | 37 | First page: | 10 |
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