{"title":"关于闭流形与有限cw -复形的同伦","authors":"Yang Su, Xiaolei Wu","doi":"10.1090/proc/15784","DOIUrl":null,"url":null,"abstract":"We study the finite generation of homotopy groups of closed manifolds and finite CW-complexes by relating it to the cohomology of their fundamental groups. Our main theorems are as follows: when $X$ is a finite CW-complex of dimension $n$ and $\\pi_1(X)$ is virtually a Poincare duality group of dimension $\\geq n-1$, then $\\pi_i(X)$ is not finitely generated for some $i$ unless $X$ is homotopy equivalent to the Eilenberg-Maclane space $K(\\pi_1(X),1)$; when $M$ is an $n$-dimensional closed manifold and $\\pi_1(M)$ is virtually a Poincare duality group of dimension $\\ge n-1$, then for some $i\\leq [n/2]$, $\\pi_i(M)$ is not finitely generated, unless $M$ itself is an aspherical manifold. These generalize theorems of M. Damian from polycyclic groups to any virtually Poincare duality groups. When $\\pi_1(X)$ is not a virtually Poincare duality group, we also obtained similar results. As a by-product of our results, we show that if a group $G$ is of type F and $H^i(G, \\mathbb{Z} G)$ is finitely generated for any $i$, then $G$ is a Poincare duality group. This recovers partially a theorem of Farrell.","PeriodicalId":8433,"journal":{"name":"arXiv: Algebraic Topology","volume":"9 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2018-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On the homotopy of closed manifolds and finite CW-complexes\",\"authors\":\"Yang Su, Xiaolei Wu\",\"doi\":\"10.1090/proc/15784\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We study the finite generation of homotopy groups of closed manifolds and finite CW-complexes by relating it to the cohomology of their fundamental groups. Our main theorems are as follows: when $X$ is a finite CW-complex of dimension $n$ and $\\\\pi_1(X)$ is virtually a Poincare duality group of dimension $\\\\geq n-1$, then $\\\\pi_i(X)$ is not finitely generated for some $i$ unless $X$ is homotopy equivalent to the Eilenberg-Maclane space $K(\\\\pi_1(X),1)$; when $M$ is an $n$-dimensional closed manifold and $\\\\pi_1(M)$ is virtually a Poincare duality group of dimension $\\\\ge n-1$, then for some $i\\\\leq [n/2]$, $\\\\pi_i(M)$ is not finitely generated, unless $M$ itself is an aspherical manifold. These generalize theorems of M. Damian from polycyclic groups to any virtually Poincare duality groups. When $\\\\pi_1(X)$ is not a virtually Poincare duality group, we also obtained similar results. As a by-product of our results, we show that if a group $G$ is of type F and $H^i(G, \\\\mathbb{Z} G)$ is finitely generated for any $i$, then $G$ is a Poincare duality group. This recovers partially a theorem of Farrell.\",\"PeriodicalId\":8433,\"journal\":{\"name\":\"arXiv: Algebraic Topology\",\"volume\":\"9 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2018-12-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv: Algebraic Topology\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1090/proc/15784\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv: Algebraic Topology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1090/proc/15784","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
On the homotopy of closed manifolds and finite CW-complexes
We study the finite generation of homotopy groups of closed manifolds and finite CW-complexes by relating it to the cohomology of their fundamental groups. Our main theorems are as follows: when $X$ is a finite CW-complex of dimension $n$ and $\pi_1(X)$ is virtually a Poincare duality group of dimension $\geq n-1$, then $\pi_i(X)$ is not finitely generated for some $i$ unless $X$ is homotopy equivalent to the Eilenberg-Maclane space $K(\pi_1(X),1)$; when $M$ is an $n$-dimensional closed manifold and $\pi_1(M)$ is virtually a Poincare duality group of dimension $\ge n-1$, then for some $i\leq [n/2]$, $\pi_i(M)$ is not finitely generated, unless $M$ itself is an aspherical manifold. These generalize theorems of M. Damian from polycyclic groups to any virtually Poincare duality groups. When $\pi_1(X)$ is not a virtually Poincare duality group, we also obtained similar results. As a by-product of our results, we show that if a group $G$ is of type F and $H^i(G, \mathbb{Z} G)$ is finitely generated for any $i$, then $G$ is a Poincare duality group. This recovers partially a theorem of Farrell.