Abstract
We obtain asymptotic equalities for the least upper bounds of deviations of the three-harmonic Poisson integrals from functions of the classes \( {W}_{\beta}^r{H}^{\alpha } \) in a uniform metric in the case r > 3, 0 ≤ 𝛼 < 1.
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Translated from Ukrains’kiĭ Matematychnyĭ Visnyk, Vol. 16, No. 3, pp. 357–371 July–September, 2019.
Translated from Ukrainian by V.V. Kukhtin
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Kal’chuk, I.V., Kravets, V.I. & Hrabova, U.Z. Approximation of the classes \( {W}_{\beta}^r{H}^{\alpha } \) by three-harmonic Poisson integrals. J Math Sci 246, 39–50 (2020). https://doi.org/10.1007/s10958-020-04721-4
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DOI: https://doi.org/10.1007/s10958-020-04721-4