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JOURNALS // Matematicheskii Sbornik // Archive

Mat. Sb., 2008 Volume 199, Number 5, Pages 3–26 (Mi sm3841)

This article is cited in 17 papers

Non-linear approximation of continuous functions by the Faber-Schauder system

M. G. Grigoryan, A. A. Sargsyan

Yerevan State University

Abstract: The existence of a function $f_0(x)\in C_{[0,1]}$ for which the greedy algorithm in the Faber-Schauder system is divergent in measure on $[0,1]$ is established. It is shown that for each $\varepsilon$, $0<\varepsilon<1$, there exists a measurable subset $E$ of $ [0,1]$ of measure $|E|>1-\varepsilon$ such that for each $f(x)\in C_{[0,1]}$ one can find a function $\widetilde f(x)\in C_{[0,1]}$ coinciding with $f(x)$ on $E$, whose greedy algorithm in the Faber-Schauder system converges uniformly on $[0,1]$.
Bibliography: 33 titles.

UDC: 517.518.8+517.518.34

MSC: 42C20, 42A20

Received: 20.02.2007 and 20.02.2008

DOI: 10.4213/sm3841


 English version:
Sbornik: Mathematics, 2008, 199:5, 629–653

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