Abstract
In this paper we study trigonometric series with general monotone coefficients, i.e., satisfying
for some \(C \ge 1\) and \(\gamma >1\). We first prove the Lebesgue-type inequalities for such series
Moreover, we obtain necessary and sufficient conditions for the sum of such series to belong to the generalized Lipschitz, Nikolskii, and Zygmund spaces. We also prove similar results for trigonometric series with weak monotone coefficients, i.e., satisfying
for some \(C \ge 1\) and \(\gamma >1\). Sharpness of the obtained results is given. Finally, we study the asymptotic results of Salem–Hardy type.
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Acknowledgements
M.D. was supported by the RFBR (No. 16-01-00350). S.T. was partially supported by MTM 2014-59174-P, 2014 SGR 289, and by the CERCA Programme of the Generalitat de Catalunya.
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Communicated by Hans G. Feichtinger.
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Dyachenko, M.I., Tikhonov, S.Y. Smoothness and Asymptotic Properties of Functions with General Monotone Fourier Coefficients. J Fourier Anal Appl 24, 1072–1097 (2018). https://doi.org/10.1007/s00041-017-9553-7
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DOI: https://doi.org/10.1007/s00041-017-9553-7
Keywords
- Fourier coefficients
- Lebesgue and Lorentz type estimates
- General and weak monotonicity
- Salem–Hardy type asymptotic results