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JOURNALS // Trudy Instituta Matematiki i Mekhaniki UrO RAN // Archive

Trudy Inst. Mat. i Mekh. UrO RAN, 2005 Volume 11, Number 2, Pages 112–119 (Mi timm193)

This article is cited in 8 papers

Divergence everywhere of subsequences of partial sums of trigonometric Fourier series

S. V. Konyagin


Abstract: It is proved that for any increasing sequence of natural numbers $\{m_j\}$ and any nondecreasing function $\varphi\colon[0,+\infty)\to[0,+\infty)$ satisfying the condition $\varphi(u)=o(u\ln\ln)$ ($u\to\infty$) there is a function $f\in L[0,2\pi]$ such that
$$ \int_0^{2\pi}\varphi(|f(x)|)\,dx<\infty, $$
and the Fourier partial sums $S_{m_j}(f)$ diverge unboundedly everywhere.

UDC: 517.518.45

Received: 20.09.2004


 English version:
Proceedings of the Steklov Institute of Mathematics (Supplement Issues), 2005, suppl. 2, S167–S175

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