Abstract
We obtain the Lp inequalities for moduli of smoothness of the generalized Liouville–Weyl derivative in terms of moduli of smoothness of a function itself. We study the limiting cases L1 and L∞.
Similar content being viewed by others
References
Bari, N.K., Steckin, S.B.: Best approximations and differential properties of two conjugate functions. Trudy Moskov. Mat. Obšč. 5, 483–522 (1956). (in Russian)
N. K. Bari, Trigonometric Series, Nauka (Moscow, 1961).
Butzer, P.L., Dyckhoff, H., Gorlich, E., Stens, R.L.: Best trigonometric approximation, fractional order derivatives and Lipschitz classes. Canad. J. Math. 29, 781–793 (1977)
R. DeVore and G. G. Lorentz, Constructive Approximation, Springer-Verlag (Berlin, 1993).
Ditzian, Z., Tikhonov, S.: Moduli of smoothnes of functions and their derivatives. Studia Math. 180, 143–160 (2007)
Ditzian, Z., Tikhonov, S.: Ul’yanov and Nikol’skii-type inequalities. J. Approx. Theory 133, 100–133 (2005)
H. Johnen and K. Scherer, On the equivalence of the \(K\)-functional and moduli of continuity and some applications, in: Constructive Theory of Functions of Several Variables (Proc. Conf., Math. Res. Inst., Oberwolfach, (1976)), Lecture Notes in Math. 571, Springer-Verlag (Berlin–Heidelberg, 1977), pp. 119–140.
Jumabayeva, A.: Liouville-Weyl derivatives, best approximations, and moduli of smoothness. Acta Math. Hungar. 145, 369–391 (2015)
Jumabayeva, A.: Sharp Ul’yanov inequalities for generalized Liouville-Weyl derivatives. Analysis Math. 43, 279–302 (2017)
Y. Kolomoitsev and S. Tikhonov, Hardy–Littlewood and Ulyanov inequalities, Memoirs of the AMS (to appear), arXiv:1711.08163.
Liflyand, E., Tikhonov, S.: A concept of general monotonicity and application. Math. Nachr. 284, 1083–1098 (2011)
Potapov, M.K., Simonov, B.V., Tikhonov, S.: Mixed moduli of smoothness in \(L_p\), \(1 < p < \infty \): a survey. Surv. Approx. Theory 8, 1–57 (2013)
M. K. Potapov, B. V. Simonov and S. Tikhonov, On the Besov and the Besov–Nikolskii classes and estimates for mixed moduli of smoothness of fractional derivatives, Tr. Mat. Inst. Steklova, 243 (2003), 244–256 (in Russian); translation in Proc. Steklov Inst. Math., 243 (2003), 234–246.
Salem, R.: Sur les transformations des séries de Fourier. Fund. Math. 33, 108–114 (1939)
Simonov, B., Tikhonov, S.: On embedings of functional classes defined by constructive characteristics. Banach Center Publ. 72, 285–307 (2006)
B. Simonov and S. Tikhonov, Embedings theorems in the constructive theory of approximations, Mat. Sb., 199 (2008), 107–148 (in Russian); translation in Sb. Math., 199 (2008), 1367–1407.
Simonov, B., Tikhonov, S.: Sharp Ul’yanov-type inequalities using fractional smoothness. J. Approx. Theory 162, 1654–1684 (2010)
S. B. Steckin, On the problem of multipliers for trigonometric polynomials, Dokl. Akad. Nauk SSSR (N.S.), 75 (1950), 165–168 (in Russian).
Steckin, S.B.: On best approximation of conjugate functions by trigonometric polynomials. Izv. Akad. Nauk SSSR Ser. Mat. 20, 197–206 (1956). (in Russian)
Taberski, R.: Differences, moduli and derivatives of fractional orders. Comment. Math. Prace Mat. 19, 389–400 (1977)
Tikhonov, S.: Weak type inequalities for moduli of smoothness: the case of limit value parameters. J. Fourier Anal. Appl. 16, 590–608 (2010)
Tikhonov, S.: Trigonometric series with general monotone coefficients. J. Math. Anal. Appl. 326, 721–735 (2007)
S. Tikhonov, Embedding results in questions of strong approximation by Fourier series, Acta Sci. Math. (Szeged), 72 (2006), 117–128; published first as S. Tikhonov, Embedding theorems of function classes, IV., CRM preprint (November 2005).
Tikhonov, S., Trebels, W.: Ulyanov-type inequalities and generalized Liouville derivatives. Proc. Roy. Soc. Edinburgh Sect. A 141, 205–224 (2011)
Trebels, W.: Inequalities for moduli of smoothness versus embeddings of function spaces. Arch. Math. 94, 155–164 (2010)
Ul’yanov, P.L.: The embedding of certain classes H\(^{\omega }_p\) of functions. Izv. Akad. Nauk SSSR Ser. Mat. 2, 601–637 (1968). (in Russian)
Uno, Y.: Lipschitz functions and convolution. Proc. Japan Acad. 50, 785–788 (1974)
A. Zygmund, Trigonometric Series, Vols. I, II, 3rd edition, Cambridge University Press (Cambridge, 2002).
Author information
Authors and Affiliations
Corresponding author
Additional information
This research was partially supported by the MTM201459174P and RFBR (grant No. 160100350), AP 05132590.
Rights and permissions
About this article
Cite this article
Jumabayeva, A., Simonov, B. Inequalities for moduli of smoothness of functions and their Liouville–Weyl derivatives. Acta Math. Hungar. 156, 1–17 (2018). https://doi.org/10.1007/s10474-018-0867-y
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10474-018-0867-y