Local and Global Approximation Theorems for Positive Linear Operators

In this paper we bridge local and global approximation theorems for positive linear operators via Ditzian–Totik moduliω2φ(f,δ) of second order whereby the step-weightsφare functions whose squares are concave. Both direct and converse theorems are derived. In particular we investigate the situation f...

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Bibliographic Details
Published in:Journal of approximation theory Vol. 94; no. 3; pp. 396 - 419
Main Author: Felten, Michael
Format: Journal Article
Language:English
Published: Elsevier Inc 01.09.1998
ISSN:0021-9045, 1096-0430
Online Access:Get full text
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Summary:In this paper we bridge local and global approximation theorems for positive linear operators via Ditzian–Totik moduliω2φ(f,δ) of second order whereby the step-weightsφare functions whose squares are concave. Both direct and converse theorems are derived. In particular we investigate the situation for exponential-type and Bernstein-type operators.
ISSN:0021-9045
1096-0430
DOI:10.1006/jath.1998.3212