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image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Results in Mathemati...arrow_drop_down
image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao
Results in Mathematics
Article . 1998 . Peer-reviewed
License: Springer TDM
Data sources: Crossref
image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao
zbMATH Open
Article . 1998
Data sources: zbMATH Open
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Degree of Simultaneous Coconvex Polynomial Approximation

Degree of simultaneous coconvex polynomial approximation
Authors: Kopotun, K.; Leviatan, D.;

Degree of Simultaneous Coconvex Polynomial Approximation

Abstract

Let \(f\in C^1[-1,1]\) change its convexity \(s\)-times at the points \(y_j\in (-1,1)\) \((j-1, \dots,s)\). Then \(f\) is approximated by polynomials \(p_n\), which are coconvex with \(f\), i.e., \(p_n\) changes its convexity exactly at the same points \(y_j\) \((j=1, \dots,s)\). It is proved that for each sufficiently large \(n\), there exists a polynomial \(p_n\) of degree \(n\), which is coconvex with \(f\) and satisfies \[ \begin{aligned} \| f-p_n \|_\infty & \leq C(s)n^{-1} \omega_2 (f^1, n^{-1}),\\ \| f'-p_n' \|_\infty & \leq C(s) \omega_2 (f',n^{-1}). \end{aligned} \] The constant \(C(s)\) is independent of \(f\), \(n\), and the location of the points \(y_j\) \((j=1, \dots, s)\). Here \(\omega_2\) denotes the second Ditzian-Totik modulus of smoothness.

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Keywords

Ditzian-Totik modules of smoothness, Approximation by polynomials, simultaneous approximation, Approximation with constraints, coconvex polynomial approximation, Rate of convergence, degree of approximation, Jackson-type estimates, Inequalities in approximation (Bernstein, Jackson, Nikol'skiĭ-type inequalities)

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
1
Average
Average
Average
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