On a certain class of approximation operators

Abstract


The paper is devoted to the study of an approximation process \(K_{n}^{H}\) representing an integral form in Kantorovich sense of Bernstein-Sheffer operators. We establish the degree of approximation both in \(C\left[ 0,1\right]\) space in terms of the modulus of continuity and \(L_{p}\left[0,1\right] ,p\geq1\), spaces in terms of the integral modulus of smoothness. Consequently, it results that the sequence \(\left( K_{n}^{H}\right)_{n\geq1}\) converges to the indentity operator in the mentioned spaces. Also we point out a connection between the smoothness of local Lipschitz \(-\alpha\left( 0<\alpha\leq1\right)\) functions and the local approximating property.

Authors

Octavian Agratini
Department of Mathematics Babes-Bolyai University, Cluj-Napoca, Romania

Keywords

approximation process; Kantorovich operator; Bernstein-Sheffer operator; r-th modulus of smoothness in Lp space

Paper coordinates

O. Agratini, On a certain class of approximation operators, Pure Mathematics and Applications, 11 (2000) no. 2, pp. 119-127

PDF

About this paper

Journal
Publisher Name
DOI
Print ISSN
Online ISSN

google scholar link

[1] F. Altomare and M. Campiti,  Korovkin-Type Approximation Theory and its Applications,  de Gruyter Series Studies in Mathematics, vol. 17, Walter de Gruyter, Berlin, New York, 1994.
[2] H. Brass,  Eine Verallgemeinerung der Bernsteinschen Operatoren,  Abhandl. Math. Sem. Hamburg, 36(1971), 211-222.
[3] Z. Ditsian and V. Totik,  Moduli of Smoothness,  springer Series in Computational Mathematics, vol.9, Springer Verlag, Berlin/Heidelberg/ New York, 1987.
[4] H. Johnen, Inequalities connected with the moduli of smmothness. Matematicki Vesnik, vol.9 (24), 1972, 3, 289-303.
[5] S. Goldberg and A. Meir,  Minimum moduli of ordinary differential operators. Proc. London Math. Soc., vol. 23(1971), 1, 1-165.
[6] A. Lupas, Approximation operators of binomial type,  in Proceedings of the International Dortmund Meeting, IDoMAT 98, Witten, Germany, Birkhauser Verlag (in print).
[7] R. Mullin and G.C. Rota,  On the foundations of combinatorial theory (III), Theory of binomial enumeration,  Graph Theory and its Applications, Academic Press, New York, 1970, 167-213.
[8] T. Popoviciu,  Remarques sur les polynomes binomiaux, Mathematica, 6 (1932), 8-10.
[9] P. Sab lonniere,  Positive Bernstein-Sheffer operators, Journal of approx. Theory, 83 (1995), 330-341.
[10] I.M. Sheffer,  Some properties of polynomials sets of type zero,  Duke Math.Journal, 5 (1939), 590-622.
[11] J.J. Swetits and B. Wood,  On the degree of  L_{p} approximation with positive linear operators, Journal of Approx. Theory, 87 (1996), 239-241.

2000

Related Posts