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On the Best Polynomial Approximations of 2π-Periodic Functions and Exact Values of n-Widths of Functional Classes in the Space L 2

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Abstract

To solve extremal problems of approximation theory in the space L 2, we use τ-moduli introduced by Ivanov. We determine the exact values of constants in Jackson-type inequalities and the exact values of n-widths of functional classes determined by these moduli.

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  1. Ukrainian Academy of Customs Service, Dnepropetrovsk

    S. B. Vakarchuk

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  1. S. B. Vakarchuk
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Vakarchuk, S.B. On the Best Polynomial Approximations of 2π-Periodic Functions and Exact Values of n-Widths of Functional Classes in the Space L 2 . Ukrainian Mathematical Journal 54, 1943–1957 (2002). https://doi.org/10.1023/A:1024017113631

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