{"title":"$\\mathcal{A}(2)$ 上的对称 A 作用","authors":"Robert R. Bruner","doi":"arxiv-2408.16980","DOIUrl":null,"url":null,"abstract":"We describe the variety of `symmetric' left actions of the mod 2 Steenrod\nalgebra $\\mathcal{A}$ on its subalgebra $\\mathcal{A}(2)$. These arise as the\ncohomology of $\\text{v}_2$ self maps $\\Sigma^7 Z \\longrightarrow Z$, as in\narXiv:1608.06250 [math.AT]. There are $256$ $\\mathbb{F}_2$ points in this\nvariety, arising from $16$ such actions of $Sq^8$ and, for each such, $16$\nactions of $Sq^{16}$. We describe in similar fashion the 1600 $\\mathcal{A}$\nactions on $\\mathcal{A}(2)$ found by Roth(1977) and the inclusion of the\nvariety of symmetric actions into the variety of all actions. We also describe\ntwo related varieties of $\\mathcal{A}$ actions, the maps between these and the\nbehavior of Spanier-Whitehead duality on these varieties. Finally, we note that\nthe actions which have been used in the literature correspond to the simplest\nchoices, in which all the coordinates equal zero.","PeriodicalId":501119,"journal":{"name":"arXiv - MATH - Algebraic Topology","volume":"44 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Symmetric A actions on $\\\\mathcal{A}(2)$\",\"authors\":\"Robert R. Bruner\",\"doi\":\"arxiv-2408.16980\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We describe the variety of `symmetric' left actions of the mod 2 Steenrod\\nalgebra $\\\\mathcal{A}$ on its subalgebra $\\\\mathcal{A}(2)$. These arise as the\\ncohomology of $\\\\text{v}_2$ self maps $\\\\Sigma^7 Z \\\\longrightarrow Z$, as in\\narXiv:1608.06250 [math.AT]. There are $256$ $\\\\mathbb{F}_2$ points in this\\nvariety, arising from $16$ such actions of $Sq^8$ and, for each such, $16$\\nactions of $Sq^{16}$. We describe in similar fashion the 1600 $\\\\mathcal{A}$\\nactions on $\\\\mathcal{A}(2)$ found by Roth(1977) and the inclusion of the\\nvariety of symmetric actions into the variety of all actions. We also describe\\ntwo related varieties of $\\\\mathcal{A}$ actions, the maps between these and the\\nbehavior of Spanier-Whitehead duality on these varieties. Finally, we note that\\nthe actions which have been used in the literature correspond to the simplest\\nchoices, in which all the coordinates equal zero.\",\"PeriodicalId\":501119,\"journal\":{\"name\":\"arXiv - MATH - Algebraic Topology\",\"volume\":\"44 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-08-30\",\"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-2408.16980\",\"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-2408.16980","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
We describe the variety of `symmetric' left actions of the mod 2 Steenrod
algebra $\mathcal{A}$ on its subalgebra $\mathcal{A}(2)$. These arise as the
cohomology of $\text{v}_2$ self maps $\Sigma^7 Z \longrightarrow Z$, as in
arXiv:1608.06250 [math.AT]. There are $256$ $\mathbb{F}_2$ points in this
variety, arising from $16$ such actions of $Sq^8$ and, for each such, $16$
actions of $Sq^{16}$. We describe in similar fashion the 1600 $\mathcal{A}$
actions on $\mathcal{A}(2)$ found by Roth(1977) and the inclusion of the
variety of symmetric actions into the variety of all actions. We also describe
two related varieties of $\mathcal{A}$ actions, the maps between these and the
behavior of Spanier-Whitehead duality on these varieties. Finally, we note that
the actions which have been used in the literature correspond to the simplest
choices, in which all the coordinates equal zero.