Powered by OpenAIRE graph
Found an issue? Give us feedback
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 Ukrainian Mathematic...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
Ukrainian Mathematical Journal
Article . 2002 . Peer-reviewed
License: Springer Nature 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
Data sources: zbMATH Open
versions View all 3 versions
addClaim

This Research product is the result of merged Research products in OpenAIRE.

You have already added 0 works in your ORCID record related to the merged Research product.

Approximation of Classes B r p,θ by Linear Methods and Best Approximations

Approximation of classes \(B_{p,\theta}^r\) by linear methods and best approximations
Authors: Romanyuk, A. S.;

Approximation of Classes B r p,θ by Linear Methods and Best Approximations

Abstract

In this paper some aspects of approximation of periodic Besov classes \(B_{p,\theta}^r= B_{p,\theta}^r(\pi_d)\), \(\pi_d=\prod_{j=1}^d[-\pi,\pi]\), \(1\leq p\leq \infty\), by linear methods, and of their best approximation by trigonometric polynomials with numbers \(k=(k_1,\dots,k_d)\) of harmonics \(e^{i(k,x)}\) from the stairwise hyperbolic cross in the space \(L_\infty(\pi_d)\) are considered. The behaviour of the norms of the sequence of the linear operators is investigated which guarantee the same order of approximation of the classes \(B_{p,\theta}^r\) in the uniform metric as their best approximations. It is shown that approximation of the classes \(B_{p,\theta}^r\), \(1<\theta<\infty\), \(1\leq p\leq 2\), by trigonometric polynomials via the linear methods in the uniform metric does not realize the order estimates of the corresponding best approximations.

Keywords

Best approximation, Chebyshev systems, best approximation by trigonometric polynomials, linear approximation methods, Fourier series and coefficients in several variables, de la Vallée Poussin kernel, Approximation by arbitrary linear expressions, Trigonometric approximation, hyperbolic cross, Function spaces arising in harmonic analysis, Sobolev spaces and other spaces of ``smooth'' functions, embedding theorems, trace theorems

  • BIP!
    Impact byBIP!
    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).
    2
    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.
    Average
    influence
    This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
    Average
    impulse
    This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
    Average
Powered by OpenAIRE graph
Found an issue? Give us feedback
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!
2
Average
Average
Average
Upload OA version
Are you the author of this publication? Upload your Open Access version to Zenodo!
It’s fast and easy, just two clicks!