Abstract
We obtain asymptotic equalities for least upper bounds of deviations in the uniform metric of de la Vallée Poussin sums on the sets C qβ H ω of Poisson integrals of functions from the class H ω generated by convex upwards moduli of continuity ω(t) which satisfy the condition ω(t)/t → ∞ as t → 0. As an implication, a solution of the Kolmogorov-Nikol’skii problem for de la Vallée Poussin sums on the sets of Poisson integrals of functions belonging to Lipschitz classes H α, 0 < α < 1, is obtained.
Реэюме
Получены асимптотические равенства для точных верхних граней уклонепий сумм Валле Пуссена в равномерной метрике на множествах C qβ H ω — интегра-лов Пуассона функций из классов H ω, порождаемых выпуклыми вверх модулями непрерывности ω(t), подчиненными условию ω(t)/t → ∞ при t → 0. В качестве следствия найдено решение задачи Колмогорова-Никольского для сумм Валле Пуссена на множествах интегралов Пуассона функций, принадлежащих классам Липшица H α, 0 < α < 1.
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Supported in part by the Ukrainian Foundation for Basic Research (Project No. GP/F36/068).
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Serdyuk, A.S., Ovsii, I.Y. Uniform approximation of Poisson integrals of functions from the class H ω by de la Vallée Poussin sums. Anal Math 38, 305–325 (2012). https://doi.org/10.1007/s10476-012-0403-1
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DOI: https://doi.org/10.1007/s10476-012-0403-1