Abstract
In this paper, we investigate the relation between the rate of convergence for the derivatives of the combinations of Baskakov operators and the smoothness for the derivatives of the functions approximated. We give some direct and inverse results on pointwise simultaneous approximation by the combinations of Baskakov operators. We also give a new equivalent result on pointwise approximation by these operators.
Similar content being viewed by others
References
Becker, M.: Global approximation theorems for Sz´asz–Mirakjan and Baskakov operators in polynomial weight spaces. Indiana Univ. Math. J., 27, 127–142 (1978)
Totik, V.: Uniform approximation by Baskakov and Meyer–K¨onig and Zeller operators. Periodica Math. Hungar, 14, 209–228 (1983)
Felten, M.: Local and global approximation theorems for positive linear operators. J. Approx. Theory, 94, 396–419 (1998)
Xie, L. S.: Direct and inverse theorems for Baskakov operators and their derivatives. Chin. Ann. of Math., 21A, 253–260 (2000)
Ditzian, Z., Jiang, D.: Approximation of functions by polynomials in C[-1, 1]. Canad. J. Math., 44, 924–940 (1992)
Ditzian, Z., Jiang, D., Leviatan D.: Simultaneous polynomial approximation. SIAM J. Math. Anal., 24, 1652–1661 (1993)
Ditzian, Z., Totik, V.: Moduli of Smoothness, Springer-Verlag, New York, 1987
Xie, L. S., Zhang, X. P.: Pointwise characterization for combinations of Baskakov operators. Approx. Theory and Its Appl., 18(2), 76–89 (2002)
Zhang, X. P., Xie, L. S.: Equivalence theorem on simultaneous approximation by combination of Baskakov operators. Math. Appl., 16(2), 54–58 (2003)
Xie, L. S.: Pointwise approximation theorems for combinations and derivatives of Baskakov operators. J. Nanjing Univ. Math. Biquarterly, 18(2), 251–260 (2001)
Berens, H., Lorentz, G. G.: Inverse theorems for Bernstein polynomials. Indiana Univ. Math. J., 21, 693–708 (1972)
Author information
Authors and Affiliations
Corresponding author
Additional information
This research is supported by the National Natural Science Foundation of China and the Zhejiang Provincial Natural Science Foundation of China
Rights and permissions
About this article
Cite this article
Xie, L.S., Shi, Z.R. Pointwise Simultaneous Approximation by Combinations of Baskakov Operators. Acta Math Sinica 23, 935–944 (2007). https://doi.org/10.1007/s10114-005-0827-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10114-005-0827-7