Abstract
The paper examines the following question: Under what orders of monotonicity are the upper and lower bounds of the sum of a cosine series near zero valid if they are obtained using the function \(\sum_{n=0}^{[\pi/x]}(n+1)\Delta(\mathbf a)_n\)?
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Funding
This work was supported by the Russian Science Foundation under grant 21-11-00131 at Lomonosov Moscow State University.
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Translated from Matematicheskie Zametki, 2021, Vol. 110, pp. 865–874 https://doi.org/10.4213/mzm13180.
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D’yachenko, M.I. Asymptotics of Sums of Cosine Series with Fractional Monotonicity Coefficients. Math Notes 110, 894–902 (2021). https://doi.org/10.1134/S0001434621110250
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DOI: https://doi.org/10.1134/S0001434621110250