Adolfo Ballester Bolinches, Maria De Falco, Francesco de Giovanni, Carmela Musella
{"title":"Groups whose proper subgroups of infinite rank have a permutability transitive relation","authors":"Adolfo Ballester Bolinches, Maria De Falco, Francesco de Giovanni, Carmela Musella","doi":"10.1515/jgth-2023-0296","DOIUrl":null,"url":null,"abstract":"\n <jats:p>Let 𝐺 be a group.\nA subgroup 𝐻 of 𝐺 is called permutable if <jats:inline-formula>\n <jats:alternatives>\n <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\n <m:mrow>\n <m:mrow>\n <m:mi>H</m:mi>\n <m:mo></m:mo>\n <m:mi>X</m:mi>\n </m:mrow>\n <m:mo>=</m:mo>\n <m:mrow>\n <m:mi>X</m:mi>\n <m:mo></m:mo>\n <m:mi>H</m:mi>\n </m:mrow>\n </m:mrow>\n </m:math>\n <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jgth-2023-0296_ineq_0001.png\"/>\n <jats:tex-math>HX=XH</jats:tex-math>\n </jats:alternatives>\n </jats:inline-formula> for all subgroups 𝑋 of 𝐺.\nPermutability is not in general a transitive relation, and 𝐺 is called a <jats:inline-formula>\n <jats:alternatives>\n <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\n <m:mi>PT</m:mi>\n </m:math>\n <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jgth-2023-0296_ineq_0002.png\"/>\n <jats:tex-math>\\mathrm{PT}</jats:tex-math>\n </jats:alternatives>\n </jats:inline-formula>-group if, whenever 𝐾 is a permutable subgroup of 𝐺 and 𝐻 is a permutable subgroup of 𝐾, we always have that 𝐻 is permutable in 𝐺. The property <jats:inline-formula>\n <jats:alternatives>\n <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\n <m:mi>PT</m:mi>\n </m:math>\n <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jgth-2023-0296_ineq_0002.png\"/>\n <jats:tex-math>\\mathrm{PT}</jats:tex-math>\n </jats:alternatives>\n </jats:inline-formula> is not inherited by subgroups, and 𝐺 is called a <jats:inline-formula>\n <jats:alternatives>\n <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\n <m:mover accent=\"true\">\n <m:mi>PT</m:mi>\n <m:mo>̄</m:mo>\n </m:mover>\n </m:math>\n <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jgth-2023-0296_ineq_0004.png\"/>\n <jats:tex-math>\\overline{\\mathrm{PT}}</jats:tex-math>\n </jats:alternatives>\n </jats:inline-formula>-group if all its subgroups have the <jats:inline-formula>\n <jats:alternatives>\n <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\n <m:mi>PT</m:mi>\n </m:math>\n <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jgth-2023-0296_ineq_0002.png\"/>\n <jats:tex-math>\\mathrm{PT}</jats:tex-math>\n </jats:alternatives>\n </jats:inline-formula>-property.\nWe prove that if 𝐺 is a soluble group of infinite rank whose proper subgroups of infinite rank have the <jats:inline-formula>\n <jats:alternatives>\n <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\n <m:mi>PT</m:mi>\n </m:math>\n <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jgth-2023-0296_ineq_0002.png\"/>\n <jats:tex-math>\\mathrm{PT}</jats:tex-math>\n </jats:alternatives>\n </jats:inline-formula>-property, then 𝐺 is a <jats:inline-formula>\n <jats:alternatives>\n <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\n <m:mover accent=\"true\">\n <m:mi>PT</m:mi>\n <m:mo>̄</m:mo>\n </m:mover>\n </m:math>\n <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jgth-2023-0296_ineq_0004.png\"/>\n <jats:tex-math>\\overline{\\mathrm{PT}}</jats:tex-math>\n </jats:alternatives>\n </jats:inline-formula>-group.</jats:p>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1515/jgth-2023-0296","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Let 𝐺 be a group.
A subgroup 𝐻 of 𝐺 is called permutable if HX=XHHX=XH for all subgroups 𝑋 of 𝐺.
Permutability is not in general a transitive relation, and 𝐺 is called a PT\mathrm{PT}-group if, whenever 𝐾 is a permutable subgroup of 𝐺 and 𝐻 is a permutable subgroup of 𝐾, we always have that 𝐻 is permutable in 𝐺. The property PT\mathrm{PT} is not inherited by subgroups, and 𝐺 is called a PT̄\overline{\mathrm{PT}}-group if all its subgroups have the PT\mathrm{PT}-property.
We prove that if 𝐺 is a soluble group of infinite rank whose proper subgroups of infinite rank have the PT\mathrm{PT}-property, then 𝐺 is a PT̄\overline{\mathrm{PT}}-group.