Abstract
We discuss the properties of the generalized translation operator generated by the system of functions \(\mathfrak{S}=\{{(\sin k\pi x)}/{(k\pi x)}\}_{k=1}^{\infty}\) in the spaces \(L^{q}=L^{q}((0,1),{\upsilon})\), \(q\geq 1\), on the interval \((0,1)\) with the weight \(\upsilon(x)=x^{2}\). We find an integral representation of this operator and study its norm in the spaces \(L^{q}\), \(1\leq q\leq\infty\). The translation operator is applied to the study of Nikol’skii’s inequality between the uniform norm and the \(L^{q}\)-norm of polynomials in the system \(\mathfrak{S}\).
REFERENCES
G. N. Watson, A Treatise on the Theory of Bessel Functions, Part 1 (Cambridge Univ., Cambridge, 1944; Inostr. Lit., Moscow, 1949).
A. Erdélyi and H. Bateman, Higher Transcendental Functions (McGraw-Hill, NewYork, 1953; Nauka, Moscow, 1966), Vol. 2.
V. S. Vladimirov, Equations of Mathematical Physics (Nauka, Moscow, 1981; Mir, Moscow, 1984).
B. M. Levitan, “Expansions into Fourier series and integrals with Bessel functions,” Usp. Mat. Nauk 6 (2), 102–143 (1951).
A. G. Babenko, “Exact Jackson–Stechkin inequality in the space \(L^{2}(\mathbb{R}^{m})\),” Trudy Inst. Mat. Mekh. UrO RAN 5, 183–198 (1998).
S. S. Platonov, “Bessel harmonic analysis and approximation of functions on the half-line,” Izv. Math., Ser. Mat. 71 (5), 1001–1048 (2007). https://doi.org/10.1070/IM2007v071n05ABEH002379
Y. Liu, “Best \(L^{2}\)-approximation of functions on \([0,1]\) with the weight \(x^{2\nu+1}\),” in Proceedings of the International Stechkin Summer School on Function Theory, Tula, Russia, 2007 (Izd. Tul’sk. Gos. Univ., Tula, 2007), pp. 180–190.
V. A. Abilov, F. V. Abilova, and M. K. Kerimov, “Some issues concerning approximations of functions by Fourier–Bessel sums,” Comput. Math. Math. Phys. 53 (7), 867–873 (2013). https://doi.org/10.1134/S0965542513070026
V. Arestov, A. Babenko, M. Deikalova, and Á. Horváth, “Nikol’skii inequality between the uniform norm and integral norm with Bessel weight for entire functions of exponential type on the half-line,” Anal. Math. 44 (1), 21–42 (2018). https://doi.org/10.1007/s10476-018-0103-6
V. V. Arestov and M. V. Deikalova, “On one generalized translation and the corresponding inequality of different metrics,” Proc. Steklov Inst. Math. 319 (Suppl. 1), S30–S42 (2022). https://doi.org/10.1134/S0081543822060049
V. Arestov and M. Deikalova, “On one inequality of different metrics for trigonometric polynomials,” Ural Math. J. 8 (2), 25–43 (2022). https://doi.org/10.15826/umj.2022.2.003
B. M. Levitan, “Application of generalized translation operators to second-order linear differential equations,” Usp. Mat. Nauk 4 (1), 1–107 (1949).
A. Gray and G. B. Mathews, A Treatise on Bessel Functions and Their Applications to Physics (Macmillan, London, 1895; Inostr. Lit., Moscow, 1953).
N. Dunford and J. Schwartz, Linear Operators: General Theory (Interscience, New York, 1958; URSS, Moscow, 2004).
I. P. Natanson, Theory of Functions of a Real Variable (Lan’, St. Petersburg, 1999) [in Russian].
E. M. Stein and G. Weiss, Introduction to Fourier Analysis on Euclidean Spaces (Princeton Univ. Press, Princeton, 1971; Mir, Moscow, 1974).
D. Jackson, “Certain problems of closest approximation,” Bull. Am. Math. Soc. 39 (12), 889–906 (1933).
S. M. Nikol’skii, “Inequalities for entire functions of finite degree and their application in the theory of differentiable functions of several variables,” Trudy MIAN SSSR 38, 244–278 (1951).
S. M. Nikol’skii, Approximation of Functions of Several Variables and Imbedding Theorems (Nauka, Moscow, 1977) [in Russian].
S. N. Bernstein, Extremal Properties of Polynomials (ONTI, Moscow, 1937) [in Russian].
N. P. Korneichuk, V. F. Babenko, and A. A. Ligun, Extremal Properties of Polynomials and Splines (Naukova Dumka, Kiev, 1992; Nova Science, New York, 1996).
G. V. Milovanović, D. S. Mitrinović, and Th. M. Rassias, Topics in Polynomials: Extremal Problems, Inequalities, Zeros (World Scientific, Singapore, 1994).
P. Borwein and T. Erdélyi, Polynomials and Polynomial Inequalities (Springer, New York, 1995).
Q. I. Rahman and G. Schmeisser, Analytic Theory of Polynomials (Oxford Univ. Press, Oxford, 2002).
V. F. Babenko, N. P. Korneichuk, V. A. Kofanov, and S. A. Pichugov, Inequalities for Derivatives and Their Applications (Naukova Dumka, Kiev, 2003) [in Russian].
N. K. Bari, “Generalization of inequalities of S. N. Bernstein and A. A. Markov,” Izv. AN SSSR, Ser. Mat. 18 (2), 159–176 (1954).
V. I. Ivanov, “Certain inequalities in various metrics for trigonometric polynomials and their derivatives,” Math. Notes 18 (4), 880–885 (1975).
V. V. Arestov, “Inequality of different metrics for trigonometric polynomials,” Math. Notes 27 (4), 265–269 (1980).
V. M. Badkov, “Asymptotic and extremal properties of orthogonal polynomials corresponding to weight having singularities,” Proc. Steklov Inst. Math. 198, 41–88 (1994).
V. Babenko, V. Kofanov, and S. Pichugov, “Comparison of rearrangement and Kolmogorov–Nagy type inequalities for periodic functions,” in Approximation Theory: A Volume Dedicated to Blagovest Sendov, Ed. by B. Bojanov (Darba, Sofia, 2002), pp. 24–53.
D. V. Gorbachev, “Sharp Bernstein–Nikolskii inequalities for polynomials and entire functions of exponential type,” Chebyshev. Sb. 22 (5), 58–110 (2021). https://doi.org/10.22405/2226-8383-2021-22-5-58-110
V. V. Arestov and M. V. Deikalova, “Nikol’skii inequality for algebraic polynomials on a multidimensional Euclidean sphere,” Proc. Steklov Inst. Math. 284 (Suppl. 1), S9–S23 (2014). https://doi.org/10.1134/S0081543814020023
V. Arestov and M. Deikalova, “Nikol’skii inequality between the uniform norm and \(L_{q}\)-norm with ultraspherical weight of algebraic polynomials on an interval,” Comput. Methods Funct. Theory 15 (4), 689–708 (2015). https://doi.org/10.1007/s40315-015-0134-y
V. Arestov and M. Deikalova, “Nikol’skii inequality between the uniform norm and \(L_{q}\)-norm with Jacobi weight of algebraic polynomials on an interval,” Analysis Math. 42 (2), 91–120 (2016). https://doi.org/10.1007/s10476-016-0201-2
V. Arestov, M. Deikalova, and Á. Horváth, “On Nikol’skii type inequality between the uniform norm and the integral \(q\)-norm with Laguerre weight of algebraic polynomials on the half-line,” J. Approx. Theory 222, 40–54 (2017). https://doi.org/10.1016/j.jat.2017.05.005
V. V. Arestov, “A characterization of extremal elements in some linear problems,” Ural Math. J. 3 (2), 22–32 (2017). https://doi.org/10.15826/umj.2017.2.004
Funding
This work was performed as a part of the research conducted in the Ural Mathematical Center and supported by the Ministry of Education and Science of the Russian Federation (agreement no. 075-02-2023-913).
Author information
Authors and Affiliations
Corresponding authors
Ethics declarations
The authors of this work declare that they have no conflicts of interest.
Additional information
Translated from Trudy Instituta Matematiki i Mekhaniki UrO RAN, Vol. 29, No. 4, pp. 27 - 48, 2023 https://doi.org/10.21538/0134-4889-2023-29-4-27-48.
Translated by M. Deikalova
Publisher's Note Pleiades Publishing remains neutral with regard to jurisdictional claims in published maps and institutional affiliations
Rights and permissions
About this article
Cite this article
Arestov, V.V., Deikalova, M.V. A Generalized Translation Operator Generated by the Sinc Function on an Interval. Proc. Steklov Inst. Math. 323 (Suppl 1), S32–S52 (2023). https://doi.org/10.1134/S0081543823060032
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0081543823060032