{"title":"On subgroups with narrow Schreier graphs","authors":"Pénélope Azuelos","doi":"10.1112/blms.13157","DOIUrl":null,"url":null,"abstract":"<p>We study finitely generated pairs of groups <span></span><math>\n <semantics>\n <mrow>\n <mi>H</mi>\n <mo>⩽</mo>\n <mi>G</mi>\n </mrow>\n <annotation>$H \\leqslant G$</annotation>\n </semantics></math> such that the Schreier graph of <span></span><math>\n <semantics>\n <mi>H</mi>\n <annotation>$H$</annotation>\n </semantics></math> has at least two ends and is <i>narrow</i>. Examples of narrow Schreier graphs include those that are quasi-isometric to finitely ended trees or have linear growth. Under this hypothesis, we show that <span></span><math>\n <semantics>\n <mi>H</mi>\n <annotation>$H$</annotation>\n </semantics></math> is a virtual fiber subgroup if and only if <span></span><math>\n <semantics>\n <mi>G</mi>\n <annotation>$G$</annotation>\n </semantics></math> contains infinitely many double cosets of <span></span><math>\n <semantics>\n <mi>H</mi>\n <annotation>$H$</annotation>\n </semantics></math>. Along the way, we prove that if a group acts essentially on a finite-dimensional CAT(0) cube complex with no facing triples, then it virtually surjects onto the integers with kernel commensurable to a hyperplane stabiliser.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"56 12","pages":"3652-3668"},"PeriodicalIF":0.8000,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.13157","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of the London Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1112/blms.13157","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
We study finitely generated pairs of groups such that the Schreier graph of has at least two ends and is narrow. Examples of narrow Schreier graphs include those that are quasi-isometric to finitely ended trees or have linear growth. Under this hypothesis, we show that is a virtual fiber subgroup if and only if contains infinitely many double cosets of . Along the way, we prove that if a group acts essentially on a finite-dimensional CAT(0) cube complex with no facing triples, then it virtually surjects onto the integers with kernel commensurable to a hyperplane stabiliser.