Abstract
Approximation properties of three-harmonic Poisson operators on the classes of (ψ, β)-differentiable functions of low smoothness given on the real axis have been studied. Asymptotic equalities have been obtained that provide in some cases a solution to the Kolmogorov–Nikol’skii problem for three-harmonic Poisson operators P3,σ(f; x) on the classes \({\widehat{C}}_{\beta ,\infty }^{\psi },\beta \in {\mathbb{R}},\) in the uniform metric.
Similar content being viewed by others
References
A. I. Stepanets, Methods of approximation theory. Pt. II. Kyiv, Inst. of Mathematics of the National Academy of Sciences of Ukraine, 2002 (in Russian).
A. I. Stepanets, Methods of approximation theory. Pt. I. Kyiv, Inst. of Mathematics of the National Academy of Sciences of Ukraine, 2002 (in Russian).
U. Z. Hrabova, “Uniform approximations by the Poisson three-harmonic integrals on the Sobolev classes,” Journal of Automation and Information Sciences, 11(2), 321–334 (2019).
A. I. Stepanets, “Classes of functions given on the real axis and their approximation by integral functions. I,” Ukr. Mat. Zhurn., 42(1), 102–112 (1990).
A. I. Stepanets, “Classes of functions given on the real axis and their approximation by integral functions. II,” Ukr. Mat. Zhurn., 42(2), 210–222 (1990).
M. H. Dzimistarishvili, Approximation of the classes of continuous functions by Sigmund operators, Preprint of the Academy of Sciences of the Ukrainian SSR (in Russian). Institute of Mathematics, 89.25, Kyiv, 3–42 (1989).
M. H. Dzimistarishvili, On the behavior of the upper bound of deviations of Steklov operators, Preprint of the Academy of Sciences of the Ukrainian SSR (in Russian). Institute of Mathematics, 90.25, Kyiv, 3–29 (1990).
O. V. Ostrovska, “Approximation of continuous functions given on the real axis by generalized Sigmund operators,” Ukr. Mat. Zhurn., 51(11), 1505–1512 (1999).
V. I. Rukasov, “Approximation of functions given on the real axis,” Ukr. Mat. Zhurn., 44(5), 682–691 (1992).
V. I. Rukasov and S. O. Chaichenko, “Approximation on the classes of functions locally integrable on the real axisby de la Vall´ee Poussin operators,” Ukr. Mat. Zhurn., 62(7), 968–978 (2010).
L. A. Repeta, Approximation of the functions of the classes by operators of the type In: Fourier series: theory and applications: Proceedings of the Institute of Mathematics of the National Academy of Sciences of Ukraine, 147–154 (1992).
V. I. Rukasov and S. O. Chaichenko, “Approximation by de la Vallée-Poussin operators on the classes of functions locally summable on the real axis,” Ukr. Math. J., 62(7), 1126–1138 (2010).
Yu.I. Kharkevych and T. V. Zhyhallo, “Approximation of functions defined on the real axis by operators generated by λ–methods of summation of their Fourier integrals,” Ukr. Math. J., 56(9), 1509–1525 (2004).
Yu. I. Kharkevych and T. V. Zhyhallo. “Approximation of (ψ, β)–differentiable functions defined on the real axis by Abel–Poisson operators,” Ukr. Math. J., 57(8), 1297–1315 (2005).
Yu. I. Kharkevych and T. V. Zhyhallo. “Approximation of functions from the class \({\widehat{C}}_{\beta ,\infty }^{\psi }\) by Poisson biharmonic operators in the uniform metric,” Ukr. Math. J., 60(5), 769–798 (2008).
Yu. I. Kharkevych and T. V. Zhyhallo. “Approximating properties of biharmonic Poisson operators in the classes \({\widehat{L}}_{\beta ,1}^{\psi }\)” Ukr. Math. J., 69(5), 757–765 (2017).
I. V. Kal’chuk, “Approximation of (ψ, β)–differentiable functions defined on the real axis by Weierstrass operators,” Ukr. Math. J., 59(9), 1342–1363 (2007).
K. M. Zhyhallo and Yu. I. Kharkevych, “On the approximation of functions of the Holder class by three-harmonic Poisson integrals,” Ukr. Math. J., 53(6), 1012–1018 (2001).
U. Z. Hrabova, “Approximation of conjugate periodic functions by their three-harmonic Poisson integrals,” Journal of Automat. and Informat. Sci., 52(10), 42–51 (2020).
S. B. Hembarska, “On boundary values of three-harmonic Poisson integral on the boundary of a unit disk,” Ukr. Math. J., 70(7), 876–884 (2018).
U. Z. Hrabova and I. V. Kal’chuk, “Approximation of the classes by three-harmonic Poisson integrals,” Carpathian Math. Publ., 11(2), 321–334 (2019).
I. V. Kal’chuk, V. I. Kravets, and U. Z. Hrabova, “Approximation of the classes by three-harmonic Poisson integrals,” J. Math. Sci., 246(2), 39–50 (2020).
U. Z. Hrabova, I. V. Kal’chuk, and L. I. Filozof, “Approximate properties of the three-harmonic Poisson integrals on the classes ” J. Math. Sci., 254(3), 397–405 (2021).
V. I. Ryazanov, “Stieltjes integrals in the theory of harmonic functions,” J. Math. Sci., 243(6), 922–933 (2019).
V. I. Ryazanov, “On the theory of the boundary behavior of conjugate harmonic functions,” Complex Anal. Oper. Theory, 13, 2899–2915 (2019).
V. Gutlyanskiĭ, V. Ryazanov, E. Yakubov, and A. Yefimushkin, “On the Hilbert boundary-value problem for Beltrami equations with singularities,” J. Math. Sci., 254(3), 357–374 (2021).
U. Hrabova and R. Tovkach, “On a boundary property of functions from a class Hp (p ≥ 1),” J. Math. Sci., 264(4), 389–395 (2022).
L. I. Bausov, “Linear methods for summation of Fourier series with given rectangular matrices. I,” Izvest. Akad. Nauk SSSR. Ser. Math., 46(3), 15–31 (1965).
U. Z. Hrabova and I. V. Kal’chuk, “Approximation of classes by three-harmonic Poisson integrals in uniform metric (low smoothness),” J. Math. Sci., 268(2), 178–191 (2022).
T. Zhyhallo and Y. Kharkevych, “On approximation of functions from the class \({L}_{\beta ,1}^{\psi }\) by the Abel–Poisson integrals in the integral metric,” Carpathian Math. Publ., 14(1), 223–229 (2022).
Author information
Authors and Affiliations
Corresponding author
Additional information
Presented by V. P. Motorny
Translated from Ukrains’kiĭ Matematychnyĭ Visnyk, Vol. 20, No. 2, pp. 186–202, April–June, 2023
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Hrabova, U.Z., Kal’chuk, I.V. Approximation of continuous functions given on the real axis by three-harmonic Poisson operators. J Math Sci 274, 327–339 (2023). https://doi.org/10.1007/s10958-023-06603-x
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10958-023-06603-x