{"title":"映射类组动作的刚性","authors":"Kathryn Mann, M. Wolff","doi":"10.2140/GT.2020.24.1211","DOIUrl":null,"url":null,"abstract":"The mapping class group $\\mathrm{Mod}_{g, 1}$ of a surface with one marked point can be identified with an index two subgroup of $\\mathrm{Aut}(\\pi_1 \\Sigma_g)$. For a surface of genus $g \\geq 2$, we show that any action of $\\mathrm{Mod}_{g, 1}$ on the circle is either semi-conjugate to its natural action on the Gromov boundary of $\\pi_1 \\Sigma_g$, or factors through a finite cyclic group. For $g \\geq 3$, all finite actions are trivial. This answers a question of Farb.","PeriodicalId":55105,"journal":{"name":"Geometry & Topology","volume":"16 1","pages":""},"PeriodicalIF":2.0000,"publicationDate":"2018-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"16","resultStr":"{\"title\":\"Rigidity of mapping class group actions on\\nS1\",\"authors\":\"Kathryn Mann, M. Wolff\",\"doi\":\"10.2140/GT.2020.24.1211\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The mapping class group $\\\\mathrm{Mod}_{g, 1}$ of a surface with one marked point can be identified with an index two subgroup of $\\\\mathrm{Aut}(\\\\pi_1 \\\\Sigma_g)$. For a surface of genus $g \\\\geq 2$, we show that any action of $\\\\mathrm{Mod}_{g, 1}$ on the circle is either semi-conjugate to its natural action on the Gromov boundary of $\\\\pi_1 \\\\Sigma_g$, or factors through a finite cyclic group. For $g \\\\geq 3$, all finite actions are trivial. This answers a question of Farb.\",\"PeriodicalId\":55105,\"journal\":{\"name\":\"Geometry & Topology\",\"volume\":\"16 1\",\"pages\":\"\"},\"PeriodicalIF\":2.0000,\"publicationDate\":\"2018-08-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"16\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Geometry & Topology\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.2140/GT.2020.24.1211\",\"RegionNum\":1,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geometry & Topology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.2140/GT.2020.24.1211","RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
The mapping class group $\mathrm{Mod}_{g, 1}$ of a surface with one marked point can be identified with an index two subgroup of $\mathrm{Aut}(\pi_1 \Sigma_g)$. For a surface of genus $g \geq 2$, we show that any action of $\mathrm{Mod}_{g, 1}$ on the circle is either semi-conjugate to its natural action on the Gromov boundary of $\pi_1 \Sigma_g$, or factors through a finite cyclic group. For $g \geq 3$, all finite actions are trivial. This answers a question of Farb.
期刊介绍:
Geometry and Topology is a fully refereed journal covering all of geometry and topology, broadly understood. G&T is published in electronic and print formats by Mathematical Sciences Publishers.
The purpose of Geometry & Topology is the advancement of mathematics. Editors evaluate submitted papers strictly on the basis of scientific merit, without regard to authors" nationality, country of residence, institutional affiliation, sex, ethnic origin, or political views.