{"title":"$ \\mathbb{Z}_{2} $- 轨道空间的同源性 $ G_{n,2}/ T^{n} $","authors":"Vladimir Ivanović, Svjetlana Terzić","doi":"arxiv-2406.11625","DOIUrl":null,"url":null,"abstract":"We study the $\\mathbb{Z}_2$-homology groups of the orbit space $X_n =\nG_{n,2}/T^n$ for the canonical action of the compact torus $T^n$ on a complex\nGrassmann manifold $G_{n,2}$. Our starting point is the model $(U_n, p_n)$ for\n$X_n$ constructed by Buchstaber and Terzi\\'c (2020), where $U_n = \\Delta\n_{n,2}\\times \\mathcal{F}_{n}$ for a hypersimplex $\\Delta_{n,2}$ and an\nuniversal space of parameters $\\mathcal{F}_{n}$ defined in Buchstaber and\nTerzi\\'c (2019), (2020). It is proved by Buchstaber and Terzi\\'c (2021) that\n$\\mathcal{F}_{n}$ is diffeomorphic to the moduli space $\\mathcal{M}_{0,n}$ of\nstable $n$-pointed genus zero curves. We exploit the results from Keel (1992)\nand Ceyhan (2009) on homology groups of $\\mathcal{M}_{0,n}$ and express them in\nterms of the stratification of $\\mathcal{F}_{n}$ which are incorporated in the\nmodel $(U_n, p_n)$. In the result we provide the description of cycles in\n$X_n$, inductively on $ n. $ We obtain as well explicit formulas for\n$\\mathbb{Z}_2$-homology groups for $X_5$ and $X_6$. The results for $X_5$\nrecover by different method the results from Buchstaber and Terzi\\'c (2021) and\nS\\\"uss (2020). The results for $X_6$ we consider to be new.","PeriodicalId":501119,"journal":{"name":"arXiv - MATH - Algebraic Topology","volume":"12 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"$ \\\\mathbb{Z}_{2} $- homology of the orbit spaces $ G_{n,2}/ T^{n} $\",\"authors\":\"Vladimir Ivanović, Svjetlana Terzić\",\"doi\":\"arxiv-2406.11625\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We study the $\\\\mathbb{Z}_2$-homology groups of the orbit space $X_n =\\nG_{n,2}/T^n$ for the canonical action of the compact torus $T^n$ on a complex\\nGrassmann manifold $G_{n,2}$. Our starting point is the model $(U_n, p_n)$ for\\n$X_n$ constructed by Buchstaber and Terzi\\\\'c (2020), where $U_n = \\\\Delta\\n_{n,2}\\\\times \\\\mathcal{F}_{n}$ for a hypersimplex $\\\\Delta_{n,2}$ and an\\nuniversal space of parameters $\\\\mathcal{F}_{n}$ defined in Buchstaber and\\nTerzi\\\\'c (2019), (2020). It is proved by Buchstaber and Terzi\\\\'c (2021) that\\n$\\\\mathcal{F}_{n}$ is diffeomorphic to the moduli space $\\\\mathcal{M}_{0,n}$ of\\nstable $n$-pointed genus zero curves. We exploit the results from Keel (1992)\\nand Ceyhan (2009) on homology groups of $\\\\mathcal{M}_{0,n}$ and express them in\\nterms of the stratification of $\\\\mathcal{F}_{n}$ which are incorporated in the\\nmodel $(U_n, p_n)$. In the result we provide the description of cycles in\\n$X_n$, inductively on $ n. $ We obtain as well explicit formulas for\\n$\\\\mathbb{Z}_2$-homology groups for $X_5$ and $X_6$. The results for $X_5$\\nrecover by different method the results from Buchstaber and Terzi\\\\'c (2021) and\\nS\\\\\\\"uss (2020). The results for $X_6$ we consider to be new.\",\"PeriodicalId\":501119,\"journal\":{\"name\":\"arXiv - MATH - Algebraic Topology\",\"volume\":\"12 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-06-17\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - MATH - Algebraic Topology\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2406.11625\",\"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 - MATH - Algebraic Topology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2406.11625","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
$ \mathbb{Z}_{2} $- homology of the orbit spaces $ G_{n,2}/ T^{n} $
We study the $\mathbb{Z}_2$-homology groups of the orbit space $X_n =
G_{n,2}/T^n$ for the canonical action of the compact torus $T^n$ on a complex
Grassmann manifold $G_{n,2}$. Our starting point is the model $(U_n, p_n)$ for
$X_n$ constructed by Buchstaber and Terzi\'c (2020), where $U_n = \Delta
_{n,2}\times \mathcal{F}_{n}$ for a hypersimplex $\Delta_{n,2}$ and an
universal space of parameters $\mathcal{F}_{n}$ defined in Buchstaber and
Terzi\'c (2019), (2020). It is proved by Buchstaber and Terzi\'c (2021) that
$\mathcal{F}_{n}$ is diffeomorphic to the moduli space $\mathcal{M}_{0,n}$ of
stable $n$-pointed genus zero curves. We exploit the results from Keel (1992)
and Ceyhan (2009) on homology groups of $\mathcal{M}_{0,n}$ and express them in
terms of the stratification of $\mathcal{F}_{n}$ which are incorporated in the
model $(U_n, p_n)$. In the result we provide the description of cycles in
$X_n$, inductively on $ n. $ We obtain as well explicit formulas for
$\mathbb{Z}_2$-homology groups for $X_5$ and $X_6$. The results for $X_5$
recover by different method the results from Buchstaber and Terzi\'c (2021) and
S\"uss (2020). The results for $X_6$ we consider to be new.