On Approximations by Trigonometric Polynomials of Classes of Functions Defined by Moduli of Smoothness

In this paper, we give a characterization of Nikol’skiĭ-Besov type classes of functions, given by integral representations of moduli of smoothness, in terms of series over the moduli of smoothness. Also, necessary and sufficient conditions in terms of monotone or lacunary Fourier coefficients for a...

Full description

Saved in:
Bibliographic Details
Main Authors: Nimete Sh. Berisha, Faton M. Berisha, Mikhail K. Potapov, Marjan Dema
Format: Article
Language:English
Published: Wiley 2017-01-01
Series:Abstract and Applied Analysis
Online Access:http://dx.doi.org/10.1155/2017/9323181
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1832560377195397120
author Nimete Sh. Berisha
Faton M. Berisha
Mikhail K. Potapov
Marjan Dema
author_facet Nimete Sh. Berisha
Faton M. Berisha
Mikhail K. Potapov
Marjan Dema
author_sort Nimete Sh. Berisha
collection DOAJ
description In this paper, we give a characterization of Nikol’skiĭ-Besov type classes of functions, given by integral representations of moduli of smoothness, in terms of series over the moduli of smoothness. Also, necessary and sufficient conditions in terms of monotone or lacunary Fourier coefficients for a function to belong to such a class are given. In order to prove our results, we make use of certain recent reverse Copson-type and Leindler-type inequalities.
format Article
id doaj-art-4a2c6d8a276b407faf81b0a4ac953de7
institution Kabale University
issn 1085-3375
1687-0409
language English
publishDate 2017-01-01
publisher Wiley
record_format Article
series Abstract and Applied Analysis
spelling doaj-art-4a2c6d8a276b407faf81b0a4ac953de72025-02-03T01:27:40ZengWileyAbstract and Applied Analysis1085-33751687-04092017-01-01201710.1155/2017/93231819323181On Approximations by Trigonometric Polynomials of Classes of Functions Defined by Moduli of SmoothnessNimete Sh. Berisha0Faton M. Berisha1Mikhail K. Potapov2Marjan Dema3Faculty of Economics, University of Prishtina, Nëna Terezë 5, Prishtina, KosovoFaculty of Mathematics and Sciences, University of Prishtina, Prishtina, KosovoDepartment of Mechanics and Mathematics, Moscow State University, Moscow 117234, RussiaFaculty of Electrical and Computer Engineering, University of Prishtina, Prishtina, KosovoIn this paper, we give a characterization of Nikol’skiĭ-Besov type classes of functions, given by integral representations of moduli of smoothness, in terms of series over the moduli of smoothness. Also, necessary and sufficient conditions in terms of monotone or lacunary Fourier coefficients for a function to belong to such a class are given. In order to prove our results, we make use of certain recent reverse Copson-type and Leindler-type inequalities.http://dx.doi.org/10.1155/2017/9323181
spellingShingle Nimete Sh. Berisha
Faton M. Berisha
Mikhail K. Potapov
Marjan Dema
On Approximations by Trigonometric Polynomials of Classes of Functions Defined by Moduli of Smoothness
Abstract and Applied Analysis
title On Approximations by Trigonometric Polynomials of Classes of Functions Defined by Moduli of Smoothness
title_full On Approximations by Trigonometric Polynomials of Classes of Functions Defined by Moduli of Smoothness
title_fullStr On Approximations by Trigonometric Polynomials of Classes of Functions Defined by Moduli of Smoothness
title_full_unstemmed On Approximations by Trigonometric Polynomials of Classes of Functions Defined by Moduli of Smoothness
title_short On Approximations by Trigonometric Polynomials of Classes of Functions Defined by Moduli of Smoothness
title_sort on approximations by trigonometric polynomials of classes of functions defined by moduli of smoothness
url http://dx.doi.org/10.1155/2017/9323181
work_keys_str_mv AT nimeteshberisha onapproximationsbytrigonometricpolynomialsofclassesoffunctionsdefinedbymoduliofsmoothness
AT fatonmberisha onapproximationsbytrigonometricpolynomialsofclassesoffunctionsdefinedbymoduliofsmoothness
AT mikhailkpotapov onapproximationsbytrigonometricpolynomialsofclassesoffunctionsdefinedbymoduliofsmoothness
AT marjandema onapproximationsbytrigonometricpolynomialsofclassesoffunctionsdefinedbymoduliofsmoothness