{"title":"Inhomogeneous Khintchine–Groshev theorem without monotonicity","authors":"Seongmin Kim","doi":"10.1112/blms.70114","DOIUrl":null,"url":null,"abstract":"<p>The Khintchine–Groshev theorem in Diophantine approximation theory says that there is a dichotomy of the Lebesgue measure of sets of <span></span><math>\n <semantics>\n <mi>ψ</mi>\n <annotation>$\\psi$</annotation>\n </semantics></math>-approximable numbers, given a monotonic function <span></span><math>\n <semantics>\n <mi>ψ</mi>\n <annotation>$\\psi$</annotation>\n </semantics></math>. Allen and Ramírez removed the monotonicity condition from the inhomogeneous Khintchine–Groshev theorem for cases with <span></span><math>\n <semantics>\n <mrow>\n <mi>n</mi>\n <mi>m</mi>\n <mo>⩾</mo>\n <mn>3</mn>\n </mrow>\n <annotation>$nm\\geqslant 3$</annotation>\n </semantics></math> and conjectured that it also holds for <span></span><math>\n <semantics>\n <mrow>\n <mi>n</mi>\n <mi>m</mi>\n <mo>=</mo>\n <mn>2</mn>\n </mrow>\n <annotation>$nm=2$</annotation>\n </semantics></math>. In this paper, we prove this conjecture in the case of <span></span><math>\n <semantics>\n <mrow>\n <mo>(</mo>\n <mi>n</mi>\n <mo>,</mo>\n <mi>m</mi>\n <mo>)</mo>\n <mo>=</mo>\n <mo>(</mo>\n <mn>2</mn>\n <mo>,</mo>\n <mn>1</mn>\n <mo>)</mo>\n </mrow>\n <annotation>$(n,m)=(2,1)$</annotation>\n </semantics></math>. We also prove it for the case of <span></span><math>\n <semantics>\n <mrow>\n <mo>(</mo>\n <mi>n</mi>\n <mo>,</mo>\n <mi>m</mi>\n <mo>)</mo>\n <mo>=</mo>\n <mo>(</mo>\n <mn>1</mn>\n <mo>,</mo>\n <mn>2</mn>\n <mo>)</mo>\n </mrow>\n <annotation>$(n,m)=(1,2)$</annotation>\n </semantics></math> with a rational inhomogeneous parameter.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 9","pages":"2639-2657"},"PeriodicalIF":0.9000,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://londmathsoc.onlinelibrary.wiley.com/doi/epdf/10.1112/blms.70114","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of the London Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://londmathsoc.onlinelibrary.wiley.com/doi/10.1112/blms.70114","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
The Khintchine–Groshev theorem in Diophantine approximation theory says that there is a dichotomy of the Lebesgue measure of sets of -approximable numbers, given a monotonic function . Allen and Ramírez removed the monotonicity condition from the inhomogeneous Khintchine–Groshev theorem for cases with and conjectured that it also holds for . In this paper, we prove this conjecture in the case of . We also prove it for the case of with a rational inhomogeneous parameter.