{"title":"关于窄Schreier图的子群","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":"{\"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}","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}
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.