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This article is cited in 39 scientific papers (total in 40 papers)
On everywhere divergence of trigonometric Fourier series
S. V. Konyagin M. V. Lomonosov Moscow State University
Abstract:
The following theorem is established.
Theorem.
{\it Let a function $\varphi\colon[0,+\infty)\to[0,+\infty)$ and a sequence $\{\psi(m)\}$ satisfy the following condition: the function $\varphi(u)/u$ is non-decreasing on $(0,+\infty)$, $\psi(m)\geqslant 1$ $(m=1,2,\dots)$ and $\varphi(m)\psi(m)=o(m\sqrt{\ln m}/\sqrt{\ln\ln m}\,)$ as $m\to\infty$. Then there is a function $f\in L[-\pi,\pi]$ such that
$$
\int _{-\pi}^\pi\varphi(|f(x)|)\,dx<\infty
$$
and $\limsup_{m\to\infty}S_m(f,x)/\psi(m)=\infty$ for all $x\in[-\pi,\pi]$ here $S_m(f)$ is the $m$-th partial sum of the trigonometric Fourier series of $f$}.
Received: 11.06.1999
Citation:
S. V. Konyagin, “On everywhere divergence of trigonometric Fourier series”, Sb. Math., 191:1 (2000), 97–120
Linking options:
https://www.mathnet.ru/eng/sm449https://doi.org/10.1070/sm2000v191n01ABEH000449 https://www.mathnet.ru/eng/sm/v191/i1/p103
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Abstract page: | 1132 | Russian version PDF: | 441 | English version PDF: | 47 | References: | 102 | First page: | 4 |
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