Everywhere Divergent
Matematičeskie zametki, Tome 80 (2006) no. 1, pp. 50-59
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For a function $f\in L^1({\mathbb T})$, we investigate the sequence
$(C,1)$ of mean values $\Phi(|S_k(x,f)-f(x)|)$, where $\Phi
(t)\colon [0,+\infty)\to [0,+\nobreak \infty)$, $\Phi (0)=\nobreak 0$, is a
continuous increasing function. We prove that if $\Phi $ increases faster
than exponentially, then these means can diverge everywhere. Divergence
almost everywhere of such means was established earlier.
Keywords:
Fourier series, means of Fourier series, the space $L^1({\mathbf T})$.
@article{MZM_2006_80_1_a6,
author = {G. A. Karagulian},
title = {Everywhere {Divergent}},
journal = {Matemati\v{c}eskie zametki},
pages = {50--59},
publisher = {mathdoc},
volume = {80},
number = {1},
year = {2006},
language = {ru},
url = {http://geodesic.mathdoc.fr/item/MZM_2006_80_1_a6/}
}
G. A. Karagulian. Everywhere Divergent. Matematičeskie zametki, Tome 80 (2006) no. 1, pp. 50-59. http://geodesic.mathdoc.fr/item/MZM_2006_80_1_a6/