Results 141 to 150 of about 4,676,398 (193)

Near-field-free super-potential FFT method for the three-dimensional free-space Poisson equation

Exl L, Schaffer S.
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The question of A*-summability of double trigonometric Fourier series

Mathematical Notes, 1972
It is proved that for anyf(x, y) ∈ L(R), where R=[-π,π,-π, π], a function ϕ(x, y), exists such that ¦ϕ(x, y) ¦=¦f(x, y) ¦ for almost all (x, y) ∈ R. The Fourier series of the function ϕ(x, y) and all conjugate trigonometric series are A*-summable almost everywhere.
L D Gogoladze
exaly   +3 more sources

Cesàro Means of Trigonometric Fourier Series

Georgian Mathematical Journal, 2002
Abstract L. Zhizhiashvili proved that if for some 𝑝, 1 ≤ 𝑝 ≤ ∞, and α ∈ (0, 1), then the 𝐿𝑝-deviation of 𝑓 from its Cesàro mean is 𝑂(𝑛 α 𝑤(1/𝑛)) where 𝑤(·) is a modulus of continuity. In this paper we show that this estimation is non-amplifiable for 𝑝 = 1.
U Goginava
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Summation of multiple trigonometric Fourier series

Mathematical Notes, 1991
See the review in Zbl 0732.42009.
R R Ashurov
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Strongly convergent trigonometric series as Fourier series

Acta Mathematica Hungarica, 1986
A real or a complex valued sequence \((s_ k)\) is strongly convergent to a number t, of index \(\lambda >0\), if \[ \frac{1}{n+1}\sum^{n}_{k=0}| (k+1)(s_ k-t)-k(s_{k-1}- t)|^{\lambda}=o(1). \] Here \(s_{-1}=0\). We write \(s_ k\to t[I]_{\lambda}\). Theorem 1. If the coefficients of a trigonometric series (1) \(a_ o| 2+\sum^{\infty}_{k=1}(a_ k\quad \cos
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Convergence of the Ces�ro means of trigonometric Fourier series

Mathematical Notes, 1983
Let f be a 2\(\pi\)-periodic function. Its maximal modulus of continuity \({\hat \omega}{}_ 1(\delta,f)\) is defined by \({\hat \omega}_ 1(\delta,f)=\sup_{\Delta}\{\sup_{| h| \leq \delta}\int_{\Delta}| f(x+h| \Delta |)-f(x)| dx ...
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Convergence of trigonometric and Walsh-Fourier series

, 2016
Summary: In this paper we present some results on convergence and summability of one- and multi-dimensional trigonometric and Walsh-Fourier series. The Fejér and Cesáro summability methods are investigated. We will prove that the maximal operator of the summability means is bounded from the corresponding classical or martingale Hardy space \(H_p\) to \(
Weisz, Ferenc
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On the Generalized Cesáro Summability of Trigonometric Fourier Series

Mathematical Notes, 2020
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Akhobadze, T. I., Zviadadze, Sh. V.
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ON TRIGONOMETRIC FOURIER SERIES

Mathematics of the USSR-Sbornik, 1976
This paper studies the problem of the convergence and summability of simple and multiple trigonometric Fourier series.Bibliography: 21 titles.
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On Fourier series in the multiple trigonometric system

Russian Mathematical Surveys, 2023
The paper gives a nice survey about the Fourier series in multiple trigonometric systems. In particular, the authors point out several results obtained previously about the phenomena of divergence of Fourier series in higher dimensions. This note can be considered a good survey for people who want to have an overview of Fourier series in multiple ...
Grigoryan, Martin G., Konyagin, Sergey V.   +1 more
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