Approximation of classes of periodic functions with small smoothness

We prove that the approximations of classes of periodic functions with small smoothness in the metrics of the spaces C and L by different linear summation methods for Fourier series are asymptotically equal to the least upper bounds of the best approximations of these classes by trigonometric polyno...

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Date:2000
Main Authors: Bushev, D. M., Бушев, Д. М.
Format: Article
Language:Ukrainian
English
Published: Institute of Mathematics, NAS of Ukraine 2000
Online Access:https://umj.imath.kiev.ua/index.php/umj/article/view/4407
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Journal Title:Ukrains’kyi Matematychnyi Zhurnal
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Ukrains’kyi Matematychnyi Zhurnal
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author Bushev, D. M.
Бушев, Д. М.
author_facet Bushev, D. M.
Бушев, Д. М.
author_sort Bushev, D. M.
baseUrl_str https://umj.imath.kiev.ua/index.php/umj/oai
collection OJS
datestamp_date 2020-03-18T20:28:32Z
description We prove that the approximations of classes of periodic functions with small smoothness in the metrics of the spaces C and L by different linear summation methods for Fourier series are asymptotically equal to the least upper bounds of the best approximations of these classes by trigonometric polynomials of degree not higher than (n - 1). We establish that the Fejér method is asymptotically the best among all positive linear approximation methods for these classes.
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spelling umjimathkievua-article-44072020-03-18T20:28:32Z Approximation of classes of periodic functions with small smoothness Наближення класів періодичних функцій з невеликою гладкістю Bushev, D. M. Бушев, Д. М. We prove that the approximations of classes of periodic functions with small smoothness in the metrics of the spaces C and L by different linear summation methods for Fourier series are asymptotically equal to the least upper bounds of the best approximations of these classes by trigonometric polynomials of degree not higher than (n - 1). We establish that the Fejér method is asymptotically the best among all positive linear approximation methods for these classes. Доведено, що наближення класів періодичних функцій з невеликою гладкістю в метриках просторів $С$ і $L$ різними лінійними методами підсумовування рядів Фур'є асимптотично рівні точним верхнім межам найкращих наближень цих класів тригонометричними поліномами степеня, що не перевищує $(n - 1)$. Встановлено, що метод Фейєра є асимптотично найкращим серед усіх додатних лінійних методів наближення цих класів. Institute of Mathematics, NAS of Ukraine 2000-02-25 Article Article application/pdf https://umj.imath.kiev.ua/index.php/umj/article/view/4407 Ukrains’kyi Matematychnyi Zhurnal; Vol. 52 No. 2 (2000); 183-196 Український математичний журнал; Том 52 № 2 (2000); 183-196 1027-3190 uk en https://umj.imath.kiev.ua/index.php/umj/article/view/4407/5518 https://umj.imath.kiev.ua/index.php/umj/article/view/4407/5519 Copyright (c) 2000 Bushev D. M.
spellingShingle Bushev, D. M.
Бушев, Д. М.
Approximation of classes of periodic functions with small smoothness
title Approximation of classes of periodic functions with small smoothness
title_alt Наближення класів періодичних функцій з невеликою гладкістю
title_full Approximation of classes of periodic functions with small smoothness
title_fullStr Approximation of classes of periodic functions with small smoothness
title_full_unstemmed Approximation of classes of periodic functions with small smoothness
title_short Approximation of classes of periodic functions with small smoothness
title_sort approximation of classes of periodic functions with small smoothness
url https://umj.imath.kiev.ua/index.php/umj/article/view/4407
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