( H p − L p ) $(H_{p}-L_{p})$ -Type inequalities for subsequences of Nörlund means of Walsh–Fourier series

Abstract We investigate the subsequence { t 2 n f } $\{t_{2^{n}}f \}$ of Nörlund means with respect to the Walsh system generated by nonincreasing and convex sequences. In particular, we prove that a large class of such summability methods are not bounded from the martingale Hardy spaces H p $H_{p}$...

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Main Authors: David Baramidze, Lars-Erik Persson, Kristoffer Tangrand, George Tephnadze
Format: Article
Language:English
Published: SpringerOpen 2023-04-01
Series:Journal of Inequalities and Applications
Subjects:
Online Access:https://doi.org/10.1186/s13660-023-02955-9
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author David Baramidze
Lars-Erik Persson
Kristoffer Tangrand
George Tephnadze
author_facet David Baramidze
Lars-Erik Persson
Kristoffer Tangrand
George Tephnadze
author_sort David Baramidze
collection DOAJ
description Abstract We investigate the subsequence { t 2 n f } $\{t_{2^{n}}f \}$ of Nörlund means with respect to the Walsh system generated by nonincreasing and convex sequences. In particular, we prove that a large class of such summability methods are not bounded from the martingale Hardy spaces H p $H_{p}$ to the space w e a k − L p $\mathit{weak-}L_{p} $ for 0 < p < 1 / ( 1 + α ) $0< p<1/(1+\alpha ) $ , where 0 < α < 1 $0<\alpha <1$ . Moreover, some new related inequalities are derived. As applications, some well-known and new results are pointed out for well-known summability methods, especially for Nörlund logarithmic means and Cesàro means.
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spelling doaj.art-442c064550af42de9ccd72f1752951842023-04-09T11:29:38ZengSpringerOpenJournal of Inequalities and Applications1029-242X2023-04-012023111310.1186/s13660-023-02955-9( H p − L p ) $(H_{p}-L_{p})$ -Type inequalities for subsequences of Nörlund means of Walsh–Fourier seriesDavid Baramidze0Lars-Erik Persson1Kristoffer Tangrand2George Tephnadze3School of Science and Technology, The University of GeorgiaDepartment of Computer Science and Computational Engineering, UiT The Arctic University of NorwayDepartment of Computer Science and Computational Engineering, UiT The Arctic University of NorwaySchool of Science and Technology, The University of GeorgiaAbstract We investigate the subsequence { t 2 n f } $\{t_{2^{n}}f \}$ of Nörlund means with respect to the Walsh system generated by nonincreasing and convex sequences. In particular, we prove that a large class of such summability methods are not bounded from the martingale Hardy spaces H p $H_{p}$ to the space w e a k − L p $\mathit{weak-}L_{p} $ for 0 < p < 1 / ( 1 + α ) $0< p<1/(1+\alpha ) $ , where 0 < α < 1 $0<\alpha <1$ . Moreover, some new related inequalities are derived. As applications, some well-known and new results are pointed out for well-known summability methods, especially for Nörlund logarithmic means and Cesàro means.https://doi.org/10.1186/s13660-023-02955-9Walsh systemNörlund meansCesàro meansNörlund logarithmic meansMartingale Hardy spaceConvergence
spellingShingle David Baramidze
Lars-Erik Persson
Kristoffer Tangrand
George Tephnadze
( H p − L p ) $(H_{p}-L_{p})$ -Type inequalities for subsequences of Nörlund means of Walsh–Fourier series
Journal of Inequalities and Applications
Walsh system
Nörlund means
Cesàro means
Nörlund logarithmic means
Martingale Hardy space
Convergence
title ( H p − L p ) $(H_{p}-L_{p})$ -Type inequalities for subsequences of Nörlund means of Walsh–Fourier series
title_full ( H p − L p ) $(H_{p}-L_{p})$ -Type inequalities for subsequences of Nörlund means of Walsh–Fourier series
title_fullStr ( H p − L p ) $(H_{p}-L_{p})$ -Type inequalities for subsequences of Nörlund means of Walsh–Fourier series
title_full_unstemmed ( H p − L p ) $(H_{p}-L_{p})$ -Type inequalities for subsequences of Nörlund means of Walsh–Fourier series
title_short ( H p − L p ) $(H_{p}-L_{p})$ -Type inequalities for subsequences of Nörlund means of Walsh–Fourier series
title_sort h p l p h p l p type inequalities for subsequences of norlund means of walsh fourier series
topic Walsh system
Nörlund means
Cesàro means
Nörlund logarithmic means
Martingale Hardy space
Convergence
url https://doi.org/10.1186/s13660-023-02955-9
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