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JOURNALS // Izvestiya Vysshikh Uchebnykh Zavedenii. Matematika // Archive

Izv. Vyssh. Uchebn. Zaved. Mat., 2018 Number 9, Pages 68–80 (Mi ivm9398)

This article is cited in 1 paper

On Vallée-Poissin means for special series with respect to ultraspherical Jacobi polynomials with sticking partial sums

I. I. Sharapudinovab, M. G. Magomed-Kasumovab

a Daghestan Scientific Center, Russian Academy of Sciences, 45 M. Gadzhiev str., Makhachkala, 367000 Russia
b Vladikavkaz Scientific Centre of the Russian Academy of Sciences

Abstract: This paper continues studying of special series with sticking property ($r$-fold coincidence at points $\pm1$) in ultraspherical Jacobi polynomials, that was started in the works of the first author. Investigation of current paper is paid on approximative properties of Vallée-Poussin means for partial sums of mentioned special series with sticking property. It is shown that for function $f$ with certain smoothness properties at the ends of interval $[-1,1]$ the weighted approximation rate by Vallée-Poussin means has the same order as the best weighted approximation of $f$.

Keywords: Jacobi polynomials, special (sticking) series of ultraspherical polynomials, approximation properties, weighted approximation, Vallée-Poussin means.

UDC: 517.521

Received: 04.08.2017


 English version:
Russian Mathematics (Izvestiya VUZ. Matematika), 2018, 62:9, 60–71

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