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Exact constants in some converse theorems for approximations by trigonometric polynomials

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Abstract

It is known that if the continuous 2π-periodic function f(x) belongs to the class w(r) (r=1, 2, ...), i.e., it has an absolutely continuous derivative of order r—1 such that we have almost everywhere

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Literature cited

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Authors and Affiliations

  1. Dnepropetrovsk Chemical Engineering Institute, USSR

    A. F. Timan & V. N. Trofimov

Authors
  1. A. F. Timan
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  2. V. N. Trofimov
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Translated from Matematicheskie Zametki, Vol. 20, No. 5, pp. 787–792, November, 1976.

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Timan, A.F., Trofimov, V.N. Exact constants in some converse theorems for approximations by trigonometric polynomials. Mathematical Notes of the Academy of Sciences of the USSR 20, 999–1002 (1976). https://doi.org/10.1007/BF01146929

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  • DOI: https://doi.org/10.1007/BF01146929

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