Linear approximation methods and the best approximations of the Poisson integrals of functions from the classes $ {H_{{\omega_p}}} $ in the metrics of the spaces L p

Autor: I. V. Sokolenko, A. S. Serdyuk
Rok vydání: 2010
Předmět:
Zdroj: Ukrainian Mathematical Journal. 62:1139-1157
ISSN: 1573-9376
0041-5995
DOI: 10.1007/s11253-010-0419-2
Popis: We obtain upper estimates for the least upper bounds of approximations of the classes of Poisson integrals of functions from $ {H_{{\omega_p}}} $ for 1 ≤ p < ∞ by a certain linear method U n * in the metric of the space L p . It is shown that the obtained estimates are asymptotically exact for p = 1: In addition, we determine the asymptotic equalities for the best approximations of the classes of Poisson integrals of functions from $ {H_{{\omega_1}}} $ in the metric of the space L 1 and show that, for these classes, the method U n * is the best polynomial approximation method in a sense of strong asymptotic behavior.
Databáze: OpenAIRE