Abstract
We give necessary and sufficient conditions for a function odd in each variable to belong to Nikol’skii classes defined via mixed modulus of smoothness and mixed derivative (both have arbitrary integer orders). These conditions are given in terms of growth of partial sums of Fourier sine coefficients with power weights or rate of decreasing to zero of these coefficients. A similar problem for generalized “small” Lipschitz classes is also treated.
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References
Antonov, A.P.: Classes \({\rm Lip}(\alpha, p)\) for double trigonometric series with monotone coefficients. Moscow Univ. Math. Bull. 63(1), 12–16 (2010)
Bary, N.K., Stechkin, S.B.: Best approximations and differential properties of two conjugate functions. Tr. Mosk. Mat. Obs. 5, 483–522 (1956) (in Russian)
Boas Jr., R.P.: Fourier series with positive coefficients. J. Math. Anal. Appl. 17, 463–483 (1967)
Butzer, P.L., Dyckhoff, H., Görlich, E., Stens, R.L.: Best trigonometric approximations, fractional order derivatives and Lipschitz classes. Canad. J. Math. 29(4), 781–793 (1977)
Donskikh, S.L.: Multiple Fourier series for functions from a Zygmund class. Moscow Univ. Math. Bull. 65(1), 1–9 (2010)
Dyachenko, M.I.: Trigonometric series with generalized-monotone coefficients. Izv. Vyssh. Uchebn. Zaved. Mat. 1986(7), 39–50 (1986) (in Russian)
Dyachenko, M.I., Tikhonov, S.Yu.: Smoothness and asymptotic properties of functions with general monotone Fourier coefficients. J. Fourier Anal. Appl. https://doi.org/10.1007/s00041-017-9553-7
Fülöp, V.: Double cosine series with nonnegative coefficients. Acta Sci. Math. (Szeged) 70(1–2), 91–100 (2004)
Fülöp, V.: Double sine series with nonnegative coefficients and Lipschitz classes. Colloq. Math. 105(1), 25–34 (2006)
Fülöp, V., Móricz, F.: Absolutely convergent multiple Fourier series and multiplicative Zygmund classes of functions. Analysis (Munich) 28(3), 345–354 (2008)
Han, D., Li, G., Yu, D.: Double sine series and higher order Lipschitz classes of functions. Bull. Math. Anal. Appl. 5(1), 10–21 (2013)
Liflyand, E., Tikhonov, S., Zeltser, M.: Extending tests for convergence of number series. J. Math. Anal. Appl. 377(1), 194–206 (2011)
Lorentz, G.G.: Fourier-Koeffizienten und Funktionenklassen. Math. Z. 51(2), 135–149 (1948)
Móricz, F.: Absolutely convergent multiple Fourier series and multiplicative Lipschitz classes of functions. Acta Math. Hungar. 121(1–2), 1–19 (2008)
Németh, J.: Fourier series with positive coefficients and generalized Lipschitz classes. Acta Sci. Math. (Szeged) 54(3–4), 291–304 (1990)
Németh, J.: Note on Fourier series with nonnegative coefficients. Acta Sci. Math. (Szeged) 55(1–2), 83–93 (1991)
Pak, I.N.: Fourier coefficients and the Lipschitz class. Anal. Math. 16(1), 57–64 (1990) (in Russian)
Potapov, M.K., Simonov, B.V., Tikhonov, S.Yu.: Mixed moduli of smoothness in \(L_p, 1<p<\infty \): a survey. Surv. Approx. Theory 8, 1–57 (2013)
Rubinstein, A.I.: On \(\omega \)-lacunary series and functions from classes \(H^\omega \). Mat. Sb. 65(107), 239–271 (1964) (in Russian)
Tevzadze, T.Sh: On certain classes of functions and Fourier series. Trudy Tbiliss. Univ. 149–150, 51–64 (1973) (in Russian)
Tikhonov, S.: On generalized Lipschitz classes and Fourier series. Z. Anal. Anwend. 23(4), 745–764 (2004)
Tikhonov, S.: Smoothness conditions and Fourier series. Math. Inequal. Appl. 10(2), 229–242 (2007)
Tikhonov, S.: Trigonometric series of Nikol’skii classes. Acta Math. Hungar. 114(1–2), 61–78 (2007)
Tikhonov, S.: Best approximation and moduli of smoothness: computation and equivalence theorems. J. Approx. Theory 153(1), 19–39 (2008)
Volosivets, S.S.: Multiple Fourier coefficients and generalized Lipschitz classes in uniform metric. J. Math. Anal. Appl. 427(2), 1070–1083 (2015)
Yu, D.: Double trigonometric series with positive coefficients. Anal. Math. 35(2), 149–167 (2009)
Zygmund, A.: Trigonometric Series, vol. 2, 2nd edn. Cambridge University Press, New York (1959)
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Volosivets, S. Multiple sine series and Nikol’skii classes in uniform metric. European Journal of Mathematics 5, 206–222 (2019). https://doi.org/10.1007/s40879-018-0226-0
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DOI: https://doi.org/10.1007/s40879-018-0226-0
Keywords
- Multiple sine series
- Mixed modulus of smoothness
- Nikol’skii classes
- Generalized “small” Lipschitz classes