Coefficients of multiple Fourier-Haar series and variational modulus of continuity

In this paper, we introduce the concept of a variational modulus of continuity for functions of several variables, give an estimate for the sum of the coefficients of a multiple Fourier-Haar series in terms of the variational modulus of continuity, and prove theorems of absolute convergence of seri...

Full description

Bibliographic Details
Main Authors: T.B. Akhazhanov, N.А. Bokayev, D.T. Matin, T. Aktosun
Format: Article
Language:English
Published: Academician Ye.A. Buketov Karaganda University 2023-12-01
Series:Қарағанды университетінің хабаршысы. Математика сериясы
Subjects:
Online Access:https://mathematics-vestnik.ksu.kz/index.php/mathematics-vestnik/article/view/602
_version_ 1797372706718482432
author T.B. Akhazhanov
N.А. Bokayev
D.T. Matin
T. Aktosun
author_facet T.B. Akhazhanov
N.А. Bokayev
D.T. Matin
T. Aktosun
author_sort T.B. Akhazhanov
collection DOAJ
description In this paper, we introduce the concept of a variational modulus of continuity for functions of several variables, give an estimate for the sum of the coefficients of a multiple Fourier-Haar series in terms of the variational modulus of continuity, and prove theorems of absolute convergence of series composed of the coefficients of multiple Fourier-Haar series. In this paper, we study the issue of the absolute convergence for multiple series composed of the Fourier-Haar coefficients of functions of several variables of bounded p-variation. We estimate the coefficients of a multiple Fourier-Haar series in terms of the variational modulus of continuity and prove the sufficiency theorem for the condition for the absolute convergence of series composed of the Fourier-Haar coefficients of the considered function class. This paper researches the question: under what conditions, imposed on the variational modulus of continuity of the fractional order of several variables functions, there is the absolute convergence for series composed of the coefficients of multiple Fourier-Haar series.
first_indexed 2024-03-08T18:39:41Z
format Article
id doaj.art-2e92a178ec3b436392b65444690754ba
institution Directory Open Access Journal
issn 2518-7929
2663-5011
language English
last_indexed 2024-03-08T18:39:41Z
publishDate 2023-12-01
publisher Academician Ye.A. Buketov Karaganda University
record_format Article
series Қарағанды университетінің хабаршысы. Математика сериясы
spelling doaj.art-2e92a178ec3b436392b65444690754ba2023-12-29T09:21:06ZengAcademician Ye.A. Buketov Karaganda UniversityҚарағанды университетінің хабаршысы. Математика сериясы2518-79292663-50112023-12-01112410.31489/2023m4/21-29602Coefficients of multiple Fourier-Haar series and variational modulus of continuityT.B. AkhazhanovN.А. BokayevD.T. MatinT. Aktosun In this paper, we introduce the concept of a variational modulus of continuity for functions of several variables, give an estimate for the sum of the coefficients of a multiple Fourier-Haar series in terms of the variational modulus of continuity, and prove theorems of absolute convergence of series composed of the coefficients of multiple Fourier-Haar series. In this paper, we study the issue of the absolute convergence for multiple series composed of the Fourier-Haar coefficients of functions of several variables of bounded p-variation. We estimate the coefficients of a multiple Fourier-Haar series in terms of the variational modulus of continuity and prove the sufficiency theorem for the condition for the absolute convergence of series composed of the Fourier-Haar coefficients of the considered function class. This paper researches the question: under what conditions, imposed on the variational modulus of continuity of the fractional order of several variables functions, there is the absolute convergence for series composed of the coefficients of multiple Fourier-Haar series. https://mathematics-vestnik.ksu.kz/index.php/mathematics-vestnik/article/view/602Fourier-Haar seriesvariational modulus of continuitycoefficients of multiple Fourier-Haar series
spellingShingle T.B. Akhazhanov
N.А. Bokayev
D.T. Matin
T. Aktosun
Coefficients of multiple Fourier-Haar series and variational modulus of continuity
Қарағанды университетінің хабаршысы. Математика сериясы
Fourier-Haar series
variational modulus of continuity
coefficients of multiple Fourier-Haar series
title Coefficients of multiple Fourier-Haar series and variational modulus of continuity
title_full Coefficients of multiple Fourier-Haar series and variational modulus of continuity
title_fullStr Coefficients of multiple Fourier-Haar series and variational modulus of continuity
title_full_unstemmed Coefficients of multiple Fourier-Haar series and variational modulus of continuity
title_short Coefficients of multiple Fourier-Haar series and variational modulus of continuity
title_sort coefficients of multiple fourier haar series and variational modulus of continuity
topic Fourier-Haar series
variational modulus of continuity
coefficients of multiple Fourier-Haar series
url https://mathematics-vestnik.ksu.kz/index.php/mathematics-vestnik/article/view/602
work_keys_str_mv AT tbakhazhanov coefficientsofmultiplefourierhaarseriesandvariationalmodulusofcontinuity
AT nabokayev coefficientsofmultiplefourierhaarseriesandvariationalmodulusofcontinuity
AT dtmatin coefficientsofmultiplefourierhaarseriesandvariationalmodulusofcontinuity
AT taktosun coefficientsofmultiplefourierhaarseriesandvariationalmodulusofcontinuity