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JOURNALS // Matematicheskie Zametki // Archive

Mat. Zametki, 2009 Volume 85, Issue 3, Pages 323–329 (Mi mzm6633)

This article is cited in 18 papers

Best Linear Approximation Methods for Functions of Taikov Classes in the Hardy spaces $H_{q,\rho}$, $q\ge1$, $0<\rho\le1$

S. B. Vakarchuka, V. I. Zabutnayab

a Ukrainian Academy of Customs
b Dnepropetrovsk National University

Abstract: In the Hardy spaces $H_{q,\rho}$, $q\ge1$, $0<\rho\le1$, we construct best linear approximation methods for classes of analytic functions $W^rH_q\Phi$, $r\in\mathbb N$, in the unit disk (studied by L. V. Taikov) whose averaged second-order moduli of continuity of the angular boundary values of the $r$th derivatives are majorized by a given function $\Phi$ satisfying certain constraints.

Keywords: linear approximation of functions, analytic function, Hardy spaces $H_{q,\rho}$, modulus of continuity, $n$-width (Bernstein, Kolmogorov, Gelfand), algebraic polynomial, Minkowski's inequality.

UDC: 517.5

Received: 18.12.2001
Revised: 08.10.2008

DOI: 10.4213/mzm6633


 English version:
Mathematical Notes, 2009, 85:3, 322–327

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© Steklov Math. Inst. of RAS, 2024