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Russian Academy of Sciences. Sbornik. Mathematics, 1995, Volume 83, Issue 1, Pages 1–22
DOI: https://doi.org/10.1070/SM1995v083n01ABEH003578
(Mi sm923)
 

This article is cited in 8 scientific papers (total in 8 papers)

Orders of moduli of continuity of operators of almost best approximation

P. V. Al'brecht
References:
Abstract: Let $X$ be a normed linear space, $Y\subset X$ a finite-dimensional subspace, $\varepsilon>0$. A multiplicative $\varepsilon$-selection $M\colon K\to Y$, where $K\subset X$, is a single-valued mapping such that
$$ \forall\,x\in K\qquad \|Mx-x\|\leqslant\inf\{\|x-y\|:y\in Y\}\cdot(1+\varepsilon). $$

It is proved in the paper that when $X=L^p(T,\Sigma,\mu)$, $1<p<\infty$, for any $Y\subset X$ and $\varepsilon>0$ there exists an $\varepsilon$-selection $M\colon K\to Y$ such that
$$ \forall\,x_1,x_2\in K\qquad \|Mx_1-Mx_2\|\leqslant c(n,p)(1+\varepsilon^{-|1/2-1/p|})\|x_1-x_2\|, $$
where the estimate is order-sharp in the space $L^p[0,1]$. It is also established that the Lipschitz constant for the $\varepsilon$-selection is of proximate order $1/\varepsilon$ in the spaces $L^1[0,1]$ and $C[0,1]$.
Received: 02.10.1992 and 21.12.1993
Bibliographic databases:
UDC: 517.5
MSC: 41A35, 41A50, 41A65
Language: English
Original paper language: Russian
Citation: P. V. Al'brecht, “Orders of moduli of continuity of operators of almost best approximation”, Russian Acad. Sci. Sb. Math., 83:1 (1995), 1–22
Citation in format AMSBIB
\Bibitem{Alb94}
\by P.~V.~Al'brecht
\paper Orders of moduli of continuity of operators of almost best approximation
\jour Russian Acad. Sci. Sb. Math.
\yr 1995
\vol 83
\issue 1
\pages 1--22
\mathnet{http://mi.mathnet.ru//eng/sm923}
\crossref{https://doi.org/10.1070/SM1995v083n01ABEH003578}
\mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=1305754}
\zmath{https://zbmath.org/?q=an:0841.41030}
\isi{https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=Publons&SrcAuth=Publons_CEL&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=A1995TQ10000001}
Linking options:
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  • https://doi.org/10.1070/SM1995v083n01ABEH003578
  • https://www.mathnet.ru/eng/sm/v185/i9/p3
  • This publication is cited in the following 8 articles:
    Citing articles in Google Scholar: Russian citations, English citations
    Related articles in Google Scholar: Russian articles, English articles
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