{"title":"用渐近 $ψ$ 密度表示子序列和子有符号序列的收敛性","authors":"Janne Heittokangas, Zinelaabidine Latreuch","doi":"arxiv-2408.03973","DOIUrl":null,"url":null,"abstract":"Given a non-negative real sequence $\\{c_n\\}_n$ such that the series\n$\\sum_{n=1}^{\\infty}c_n$ diverges, it is known that the size of an infinite\nsubset $A\\subset\\mathbb{N}$ can be measured in terms of the linear density such\nthat the sub-series $\\sum_{n\\in A}c_n$ either (a) converges or (b) still\ndiverges. The purpose of this research is to study these convergence/divergence\nquestions by measuring the size of the set $A\\subset\\mathbb{N}$ in a more\nprecise way in terms of the recently introduced asymptotic $\\psi$-density. The\nconvergence of the associated sub-signed series $\\sum_{n=1 }^{\\infty}m_nc_n$ is\nalso discussed, where $\\{m_n\\}_n$ is a real sequence with values restricted to\nthe set $\\{-1, 0, 1\\}$.","PeriodicalId":501145,"journal":{"name":"arXiv - MATH - Classical Analysis and ODEs","volume":"30 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Convergence of sub-series' and sub-signed series' in terms of the asymptotic $ψ$-density\",\"authors\":\"Janne Heittokangas, Zinelaabidine Latreuch\",\"doi\":\"arxiv-2408.03973\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Given a non-negative real sequence $\\\\{c_n\\\\}_n$ such that the series\\n$\\\\sum_{n=1}^{\\\\infty}c_n$ diverges, it is known that the size of an infinite\\nsubset $A\\\\subset\\\\mathbb{N}$ can be measured in terms of the linear density such\\nthat the sub-series $\\\\sum_{n\\\\in A}c_n$ either (a) converges or (b) still\\ndiverges. The purpose of this research is to study these convergence/divergence\\nquestions by measuring the size of the set $A\\\\subset\\\\mathbb{N}$ in a more\\nprecise way in terms of the recently introduced asymptotic $\\\\psi$-density. The\\nconvergence of the associated sub-signed series $\\\\sum_{n=1 }^{\\\\infty}m_nc_n$ is\\nalso discussed, where $\\\\{m_n\\\\}_n$ is a real sequence with values restricted to\\nthe set $\\\\{-1, 0, 1\\\\}$.\",\"PeriodicalId\":501145,\"journal\":{\"name\":\"arXiv - MATH - Classical Analysis and ODEs\",\"volume\":\"30 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-08-07\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - MATH - Classical Analysis and ODEs\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2408.03973\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - MATH - Classical Analysis and ODEs","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2408.03973","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Convergence of sub-series' and sub-signed series' in terms of the asymptotic $ψ$-density
Given a non-negative real sequence $\{c_n\}_n$ such that the series
$\sum_{n=1}^{\infty}c_n$ diverges, it is known that the size of an infinite
subset $A\subset\mathbb{N}$ can be measured in terms of the linear density such
that the sub-series $\sum_{n\in A}c_n$ either (a) converges or (b) still
diverges. The purpose of this research is to study these convergence/divergence
questions by measuring the size of the set $A\subset\mathbb{N}$ in a more
precise way in terms of the recently introduced asymptotic $\psi$-density. The
convergence of the associated sub-signed series $\sum_{n=1 }^{\infty}m_nc_n$ is
also discussed, where $\{m_n\}_n$ is a real sequence with values restricted to
the set $\{-1, 0, 1\}$.