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JOURNALS // Matematicheskii Sbornik // Archive

Mat. Sb., 2009 Volume 200, Number 7, Pages 107–130 (Mi sm4523)

This article is cited in 14 papers

Trigonometric Padé approximants for functions with regularly decreasing Fourier coefficients

Yu. A. Labych, A. P. Starovoitov

Francisk Skorina Gomel State University

Abstract: Sufficient conditions describing the regular decrease of the coefficients of a Fourier series $f(x)=a_0/2+\sum a_n\cos{kx}$ are found which ensure that the trigonometric Padé approximants $\pi^t_{n,m}(x;f)$ converge to the function $f$ in the uniform norm at a rate which coincides asymptotically with the highest possible one. The results obtained are applied to problems dealing with finding sharp constants for rational approximations.
Bibliography: 31 titles.

Keywords: Fourier series, trigonometric Padé approximants, Padé-Chebyshev approximants, best rational approximations.

UDC: 517.538.52+517.538.53+517.518.84

MSC: Primary 41A20, 41A25; Secondary 41A21, 41A44

Received: 21.02.2008 and 13.01.2009

DOI: 10.4213/sm4523


 English version:
Sbornik: Mathematics, 2009, 200:7, 1051–1074

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© Steklov Math. Inst. of RAS, 2025