Titlebook: Geometric Approximation Theory; Alexey R. Alimov,Igor’ G. Tsar’kov Book 2021 The Editor(s) (if applicable) and The Author(s), under exclus

CRASS

John Fry,Gerald Sandler,David Brooksce. In this chapter, we consider the problem of approximating a set by a class of sets. In this problem, it is not only the evaluation of the approximation that is important, but also the set that best approximates this class (an optimal set).

异教徒

Comparative Epidemiology Experiment: Brazil,ple, classes of finite-dimensional subspaces (nested or not nested), classes of nonlinear objects defined by a certain parameter or by a set of parameters. In particular, this problem includes the classical Bernstein’s problem of approximation of an element by a fixed family of nested planes or the

ILEUM

Mosaic

1439-7382 ts and related problems, presenting novel results throughout the section. This text is suitable for both theoretical and applied viewpoints and e978-3-030-90953-6978-3-030-90951-2Series ISSN 1439-7382 Series E-ISSN 2196-9922

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Ruptured-Disk

,Chebyshev Alternation Theorem. Haar’s and Mairhuber’s Theorems,es .(.), we give several results that either characterize or give sufficient conditions for the existence of Chebyshev subspaces in .(.). Among such conditions, we mention de la Vallée Poussin’s estimates (see Sect. .), the Haar characterization property (see Sect. .), and Mairhuber’s theorem (see S

Ossification

混合物

Existence. Compact, Boundedly Compact, Approximatively Compact, and ,-Compact Sets. Continuity of tcept of boundedly compact sets (an intersection of such a set with a closed ball is compact). Further generalization of this concept gives rise to the important concept of approximative compactness (see Definition 4.2 below) introduced by Efimov and Stechkin in the 1950s. An approximatively compact