Abstract
We prove a direct theorem for shape preserving Lp-approximation, 0<p<∞, in terms of the classical modulus of smoothness w2(f, tp1). This theorem may be regarded as an extension to Lp of the well-known pointwise estimates of the Timan type and their shape-preserving variants of R. DeVore, D. Leviatan, and X. M. Yu. It leads to a characterization of monotone and convex functions in Lipschitz classes (and more general Besov spaces) in terms of their approximation by algebraic polynomials.
Original language | English |
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Pages (from-to) | 299-319 |
Number of pages | 21 |
Journal | Constructive Approximation |
Volume | 11 |
Issue number | 3 |
DOIs | |
State | Published - Sep 1995 |
Keywords
- AMS classification: 41A10, 41A25, 41A29
- Degree of monotone approximation
- Polynomial approximation in L