Correct order on some certain weighted representation functions

Let $\mathbb{N}$ be the set of all nonnegative integers. For any positive integer $k$ and any subset $A$ of nonnegative integers, let $r_{1,k}(A,n)$ be the number of solutions $(a_1,a_2)$ to the equation $n=a_1+ka_2$. In 2016, Qu proved that \[ \liminf _{n\,\rightarrow \,\infty }r_{1,k}(A,n)=\infty...

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Main Authors: Chen, Shi-Qiang, Ding, Yuchen, Lü, Xiaodong, Zhang, Yuhan
Format: Article
Language:English
Published: Académie des sciences 2024-05-01
Series:Comptes Rendus. Mathématique
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Online Access:https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.573/
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author Chen, Shi-Qiang
Ding, Yuchen
Lü, Xiaodong
Zhang, Yuhan
author_facet Chen, Shi-Qiang
Ding, Yuchen
Lü, Xiaodong
Zhang, Yuhan
author_sort Chen, Shi-Qiang
collection DOAJ
description Let $\mathbb{N}$ be the set of all nonnegative integers. For any positive integer $k$ and any subset $A$ of nonnegative integers, let $r_{1,k}(A,n)$ be the number of solutions $(a_1,a_2)$ to the equation $n=a_1+ka_2$. In 2016, Qu proved that \[ \liminf _{n\,\rightarrow \,\infty }r_{1,k}(A,n)=\infty \] providing that $r_{1,k}(A,n)=r_{1,k}(\mathbb{N}\setminus A,n)$ for all sufficiently large integers, which answered affirmatively a 2012 problem of Yang and Chen. In a very recent article, another Chen (the first named author) slightly improved Qu’s result and obtained that \[ \liminf _{n\,\rightarrow \,\infty }\frac{r_{1,k}(A,n)}{\log n}>0. \] In this note, we further improve the lower bound on $r_{1,k}(A,n)$ by showing that \[ \liminf _{n\,\rightarrow \,\infty }\frac{r_{1,k}(A,n)}{n}>0. \] Our bound reflects the correct order of magnitude of the representation function $r_{1,k}(A,n)$ under the above restrictions due to the trivial fact that $r_{1,k}(A,n)\le n/k.$
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spelling doaj-art-9ded25a3590d43709522fe8dff3aea682025-02-07T11:21:12ZengAcadémie des sciencesComptes Rendus. Mathématique1778-35692024-05-01362G554755210.5802/crmath.57310.5802/crmath.573Correct order on some certain weighted representation functionsChen, Shi-Qiang0Ding, Yuchen1Lü, Xiaodong2Zhang, Yuhan3School of Mathematics and Statistics, Anhui Normal University, Wuhu 241002, People’s Republic of ChinaSchool of Mathematical Sciences, Yangzhou University, Yangzhou 225002, People’s Republic of ChinaSchool of Mathematical Sciences, Yangzhou University, Yangzhou 225002, People’s Republic of ChinaSchool of Mathematical Sciences, Yangzhou University, Yangzhou 225002, People’s Republic of ChinaLet $\mathbb{N}$ be the set of all nonnegative integers. For any positive integer $k$ and any subset $A$ of nonnegative integers, let $r_{1,k}(A,n)$ be the number of solutions $(a_1,a_2)$ to the equation $n=a_1+ka_2$. In 2016, Qu proved that \[ \liminf _{n\,\rightarrow \,\infty }r_{1,k}(A,n)=\infty \] providing that $r_{1,k}(A,n)=r_{1,k}(\mathbb{N}\setminus A,n)$ for all sufficiently large integers, which answered affirmatively a 2012 problem of Yang and Chen. In a very recent article, another Chen (the first named author) slightly improved Qu’s result and obtained that \[ \liminf _{n\,\rightarrow \,\infty }\frac{r_{1,k}(A,n)}{\log n}>0. \] In this note, we further improve the lower bound on $r_{1,k}(A,n)$ by showing that \[ \liminf _{n\,\rightarrow \,\infty }\frac{r_{1,k}(A,n)}{n}>0. \] Our bound reflects the correct order of magnitude of the representation function $r_{1,k}(A,n)$ under the above restrictions due to the trivial fact that $r_{1,k}(A,n)\le n/k.$https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.573/representation functionsorder of functionspartitions of integers
spellingShingle Chen, Shi-Qiang
Ding, Yuchen
Lü, Xiaodong
Zhang, Yuhan
Correct order on some certain weighted representation functions
Comptes Rendus. Mathématique
representation functions
order of functions
partitions of integers
title Correct order on some certain weighted representation functions
title_full Correct order on some certain weighted representation functions
title_fullStr Correct order on some certain weighted representation functions
title_full_unstemmed Correct order on some certain weighted representation functions
title_short Correct order on some certain weighted representation functions
title_sort correct order on some certain weighted representation functions
topic representation functions
order of functions
partitions of integers
url https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.573/
work_keys_str_mv AT chenshiqiang correctorderonsomecertainweightedrepresentationfunctions
AT dingyuchen correctorderonsomecertainweightedrepresentationfunctions
AT luxiaodong correctorderonsomecertainweightedrepresentationfunctions
AT zhangyuhan correctorderonsomecertainweightedrepresentationfunctions