Abstract

This note is devoted to the study of a linear positive sequence of operators representing an integral form in Kantorovich’s sense. We prove that this sequence converges to the identity operator in \(Lp([0,1]),\) \(p\geq1,\) spaces. By using the \(r\)-th order \((r=1\) and \(r\geq3)\) modulus of smoothness measured in these spaces, we establish an upper bound of the approximation error. Also, we point out a connection between the smoothness of \(\alpha\)-H\”{o}lder \((0<\alpha \leq1)\) functions and the local approximation property.

Authors

Octavian Agratini
Tiberiu Popoviciu Institute of Numerical Analysis, Romanian Academy

Keywords

Positive linear operator; Kantorovich-type operator; Lp space, rate of convergence; Bohman-Korovkin theorem; r-modulus of smoothness; K-functional; Hardy-Littlewood maximal operator.

Paper coordinates

O. Agratini, On Kantorovich-type operators in Lp spaces, WSEAS Transactions on Mathematics, 23 (2024), pp. 1033-1038, https://doi.org/10.37394/23206.2024.23.106

PDF

About this paper

Journal

Wseas Transactions on Mathematics

Publisher Name

WSEAS

Print ISSN

1109-2769

Online ISSN

2224-2880

google scholar link

[1] L.V. Kantorovich, Sur certains développements suivant les polynômes de la forme de S. Bernstein, I, II, C.R. Acad. URSS, (1930), 563-568, 595-600.
[2] P. L. Butzer, On the extensions of Bernstein polynomials to the infinite interval, Proc. Amer. Math. Soc., 5(1954), 547-553.
[3] Z. Ditzian, V. Totik, Moduli of Smoothness, Springer-Verlag, New York Inc., 1987.
[4] Q. Razi, Approximation of a function by Kantorovich type operators, Math. Vesnik, vol. 41(1989), No. 3, 183-192, [Online]. http://eudml.org/doc/260465 (Accessed Date:October 5, 2024).
[5] A. Habib, A. Wafi, Degree of approximation of functions by modified Bernstein polynomials on an unbounded interval, Indian J. Pure Appl. Math., 8(6)(1977), 691-695.
[6] F. Altomare, M. Cappelletti Montano, V. Leonessa, Kantorovich-type modifications of certain discrete-type operators on the positive real axis, Note Mat., 43(2023), no. 1, 15-40. DOI: 10.1285/i15900932v43n1p15.
[7] L. Angeloni, G. Vinti, Multidimensional sampling-Kantorovich operators in BVspaces, Open Math., 21(2023), no. 1, pp. 20220573, http://dx.doi.org/10.1515/math2022-057
[8] M. Kara, N. I. Mahmudov, Approximation theorems for complex α-Bernstein-Kantorovich operators, Results Math., 79(2024), art. no. 72. https://doi.org/10.1007/s00025-023-02101-3.
[9] O. Agratini, An approximation process of Kantorovich type, Miskolc Math. Notes, 2(2001),. No. 1, 3-10, https://doi.org/10.18514/MMN.2001.31.
[10] F. Altomare, V. Leonessa, On a sequence of positive linear operators associated with a continuous selection of Borel measures, Mediterr. J. Math., 3(2006), 363-382. https://doi.org/10.1007/s00009-006-0084-8.
[11] Ö. Dalmanoglu, O. Dogru, On statistical approximation properties of Kantorovich type q-Bernstein operators, Math. Comput. Model., 52(2010), 760-771, https://doi.org/10.1016/j.mcm.2010.05.005.
[12] M.-Y. Ren, X.-M. Zeng, Some statistical approximation properties of Kantorovich-type q-Bernstein-Stancu operators, J. Inequal. Appl., 2014(2014), art. no. 10.
https://doi.org/10.1186/1029-242X-2014-10.
[13] H. Bohman, On approximation of continuous and of analytic functions, Ark. Math., 2(1952), No. 1, 43-56.
[14] P. P. Korovkin, Convergence of linear positive operators in the space of continuous functions (Russian), Dokl. Akad. Nauk SSSR, 90(1953), 961-964.
[15] O. Agratini, Kantorovich-type operators preserving affine functions, Hacet. J. Math. Stat., 45(2016), Issue 6, 1957-1663, DOI : 10.15672/HJMS.20164515994.
[16] R. A. DeVore, G. G. Lorentz, Constructive Approximation, Grundlehren der Mathematischen Wissenschaften, 303, Springer-Verlag, Berlin, Heidelberg, 1993.
[17] F. Altomare, Korovkin-type theorems and approximation by positive linear operators, Surveys in Approximation Theory, 5(2010), 92-164.
[18] J. Peetre, A Theory of Interpolation of Normed Spaces, Notes Universidade de Brasilia, 1963.
[19] H. Johnen, Inequalities connected with the moduli of smoothness, Mat. Vesnik, 24(1972), No. 1, 289-305.
[20] E. M. Stein, Singular Integrals and Differentia-bility Properties of Functions, Princeton University Press, 1970.
[21] J. J. Swetits, B. Wood, Note on the degree of p L approximation with positive linear operators, J. Approx. Theory, 87(1996), 239-241, art. no. 0103, https://doi.org/10.1006/jath.1996.0103.
[22] S. Goldberg, A. Meir, Minimum moduli of ordinary differential operators, Proc. London Math. Soc., 23(1971), No. 1, 1-15.

2024

Related Posts