Spectral inequalities involving the sums and products of functions

In this paper, the notation ≺ and ≺≺ denote the Hardy-Littlewood-Pólya spectral order relations for measurable functions defined on a fnite measure space (X,Λ,μ) with μ(X)=a, and expressions of the form f≺g and f≺≺g are called spectral inequalities. If f,g∈L1(X,Λ,μ), it is proven that, for some b≥0,...

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Main Author: Kong-Ming Chong
Format: Article
Language:English
Published: Wiley 1982-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Subjects:
Online Access:http://dx.doi.org/10.1155/S0161171282000143
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author Kong-Ming Chong
author_facet Kong-Ming Chong
author_sort Kong-Ming Chong
collection DOAJ
description In this paper, the notation ≺ and ≺≺ denote the Hardy-Littlewood-Pólya spectral order relations for measurable functions defined on a fnite measure space (X,Λ,μ) with μ(X)=a, and expressions of the form f≺g and f≺≺g are called spectral inequalities. If f,g∈L1(X,Λ,μ), it is proven that, for some b≥0, log[b+(δfιg)+]≺≺log[b+(fg)+]≺≺log[b+(δfδg)+] whenever log+[b+(δfδg)+]∈L1([0,a]), here δ and ι respectively denote decreasing and increasing rearrangement. With the particular case b=0 of this result, the Hardy-Littlewood-Pólya-Luxemburg spectral inequality fg≺≺δfδg for 0≤f, g∈L1(X,Λ,μ) is shown to be a consequence of the well-known but seemingly unrelated spectral inequality f+g≺δf+δg (where f,g∈L1(X,Λ,μ)), thus giving new proof for the former spectral inequality. Moreover, the Hardy-Littlewood-Pólya-Luxemburg spectral inequality is also tended to give (δfιg)+≺≺(fg)+≺≺(δfδg)+ and (δfδg)−≺≺(fg)−≺≺(δfιg)− for not necessarily non-negative f,g∈L1(X,Λ,μ).
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spelling doaj-art-9d449da0d42645cab21f475136947fea2025-02-03T01:21:19ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04251982-01-015114115710.1155/S0161171282000143Spectral inequalities involving the sums and products of functionsKong-Ming Chong0Department of Mathematics, University of Malaya, Kuala Lumpur 22-11, MalaysiaIn this paper, the notation ≺ and ≺≺ denote the Hardy-Littlewood-Pólya spectral order relations for measurable functions defined on a fnite measure space (X,Λ,μ) with μ(X)=a, and expressions of the form f≺g and f≺≺g are called spectral inequalities. If f,g∈L1(X,Λ,μ), it is proven that, for some b≥0, log[b+(δfιg)+]≺≺log[b+(fg)+]≺≺log[b+(δfδg)+] whenever log+[b+(δfδg)+]∈L1([0,a]), here δ and ι respectively denote decreasing and increasing rearrangement. With the particular case b=0 of this result, the Hardy-Littlewood-Pólya-Luxemburg spectral inequality fg≺≺δfδg for 0≤f, g∈L1(X,Λ,μ) is shown to be a consequence of the well-known but seemingly unrelated spectral inequality f+g≺δf+δg (where f,g∈L1(X,Λ,μ)), thus giving new proof for the former spectral inequality. Moreover, the Hardy-Littlewood-Pólya-Luxemburg spectral inequality is also tended to give (δfιg)+≺≺(fg)+≺≺(δfδg)+ and (δfδg)−≺≺(fg)−≺≺(δfιg)− for not necessarily non-negative f,g∈L1(X,Λ,μ).http://dx.doi.org/10.1155/S0161171282000143equimeasurable rearrangementsspectral inequalitiesconvex functionsdiscrete measurenon-atomic measuremartingale convergence theorem.
spellingShingle Kong-Ming Chong
Spectral inequalities involving the sums and products of functions
International Journal of Mathematics and Mathematical Sciences
equimeasurable rearrangements
spectral inequalities
convex functions
discrete measure
non-atomic measure
martingale convergence theorem.
title Spectral inequalities involving the sums and products of functions
title_full Spectral inequalities involving the sums and products of functions
title_fullStr Spectral inequalities involving the sums and products of functions
title_full_unstemmed Spectral inequalities involving the sums and products of functions
title_short Spectral inequalities involving the sums and products of functions
title_sort spectral inequalities involving the sums and products of functions
topic equimeasurable rearrangements
spectral inequalities
convex functions
discrete measure
non-atomic measure
martingale convergence theorem.
url http://dx.doi.org/10.1155/S0161171282000143
work_keys_str_mv AT kongmingchong spectralinequalitiesinvolvingthesumsandproductsoffunctions