{"title":"每个霍普夫-伽罗瓦对应关系都是双射的类型分类","authors":"Lorenzo Stefanello , Cindy Tsang Sin Yi","doi":"10.1016/j.jalgebra.2024.10.010","DOIUrl":null,"url":null,"abstract":"<div><div>Let <span><math><mi>L</mi><mo>/</mo><mi>K</mi></math></span> be any finite Galois extension with Galois group <em>G</em>. It is known by Chase and Sweedler that the Hopf–Galois correspondence is injective for every Hopf–Galois structure on <span><math><mi>L</mi><mo>/</mo><mi>K</mi></math></span>, but it need not be bijective in general. Hopf–Galois structures are known to be related to skew braces, and recently, the first-named author and Trappeniers proposed a new version of this connection with the property that the intermediate fields of <span><math><mi>L</mi><mo>/</mo><mi>K</mi></math></span> in the image of the Hopf–Galois correspondence are in bijection with the left ideals of the associated skew brace. As an application, they classified the groups <em>G</em> for which the Hopf–Galois correspondence is bijective for every Hopf–Galois structure on any <em>G</em>-Galois extension. In this paper, using a similar approach, we shall classify the groups <em>N</em> for which the Hopf–Galois correspondence is bijective for every Hopf–Galois structure of type <em>N</em> on any Galois extension.</div></div>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Classification of the types for which every Hopf–Galois correspondence is bijective\",\"authors\":\"Lorenzo Stefanello , Cindy Tsang Sin Yi\",\"doi\":\"10.1016/j.jalgebra.2024.10.010\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Let <span><math><mi>L</mi><mo>/</mo><mi>K</mi></math></span> be any finite Galois extension with Galois group <em>G</em>. It is known by Chase and Sweedler that the Hopf–Galois correspondence is injective for every Hopf–Galois structure on <span><math><mi>L</mi><mo>/</mo><mi>K</mi></math></span>, but it need not be bijective in general. Hopf–Galois structures are known to be related to skew braces, and recently, the first-named author and Trappeniers proposed a new version of this connection with the property that the intermediate fields of <span><math><mi>L</mi><mo>/</mo><mi>K</mi></math></span> in the image of the Hopf–Galois correspondence are in bijection with the left ideals of the associated skew brace. As an application, they classified the groups <em>G</em> for which the Hopf–Galois correspondence is bijective for every Hopf–Galois structure on any <em>G</em>-Galois extension. In this paper, using a similar approach, we shall classify the groups <em>N</em> for which the Hopf–Galois correspondence is bijective for every Hopf–Galois structure of type <em>N</em> on any Galois extension.</div></div>\",\"PeriodicalId\":0,\"journal\":{\"name\":\"\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0,\"publicationDate\":\"2024-10-16\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0021869324005489\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0021869324005489","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
让 L/K 是任何具有伽罗瓦群 G 的有限伽罗瓦扩展。Chase 和 Sweedler 已知,对于 L/K 上的每一个 Hopf-Galois 结构,Hopf-Galois 对应都是注入式的,但在一般情况下不一定是双射的。众所周知,Hopf-Galois 结构与斜撑相关,最近,第一作者和 Trappeniers 提出了这一联系的新版本,其性质是在 Hopf-Galois 对应的映像中,L/K 的中间域与相关斜撑的左理想是双射的。作为一种应用,他们对任何 G-Galois 扩展上的每个 Hopf-Galois 结构的 Hopf-Galois 对应都是双射的群 G 进行了分类。在本文中,我们将采用类似的方法,对 N 群进行分类,对于这些群,在任何伽罗瓦扩展上的每一个 N 型 Hopf-Galois 结构,Hopf-Galois 对应都是双射的。
Classification of the types for which every Hopf–Galois correspondence is bijective
Let be any finite Galois extension with Galois group G. It is known by Chase and Sweedler that the Hopf–Galois correspondence is injective for every Hopf–Galois structure on , but it need not be bijective in general. Hopf–Galois structures are known to be related to skew braces, and recently, the first-named author and Trappeniers proposed a new version of this connection with the property that the intermediate fields of in the image of the Hopf–Galois correspondence are in bijection with the left ideals of the associated skew brace. As an application, they classified the groups G for which the Hopf–Galois correspondence is bijective for every Hopf–Galois structure on any G-Galois extension. In this paper, using a similar approach, we shall classify the groups N for which the Hopf–Galois correspondence is bijective for every Hopf–Galois structure of type N on any Galois extension.