{"title":"相对极大子群的约简定理","authors":"W. Guo, D. Revin, E. Vdovin","doi":"10.1142/s1664360721500016","DOIUrl":null,"url":null,"abstract":"Let $\\mathfrak{X}$ be a class of finite groups closed under taking subgroups, homomorphic images and extensions. It is known that if $A$ is a normal subgroup of a finite group $G$ then the image of an $\\mathfrak{X}$-maximal subgroup $H$ of $G$ in $G/A$ is not, in general, $\\mathfrak{X}$-maximal in $G/A$. We say that the reduction $\\mathfrak{X}$-theorem holds for a finite group $A$ if, for every finite group $G$ that is an extension of $A$ (i. e. contains $A$ as a normal subgroup), the number of conjugacy classes of $\\mathfrak{X}$-maximal subgroups in $G$ and $G/A$ is the same. The reduction $\\mathfrak{X}$-theorem for $A$ implies that $HA/A$ is $\\mathfrak{X}$-maximal in $G/A$ for every extension $G$ of $A$ and every $\\mathfrak{X}$-maximal subgroup $H$ of $G$. In this paper, we prove that the reduction $\\mathfrak{X}$-theorem holds for $A$ if and only if all $\\mathfrak{X}$-maximal subgroups are conjugate in $A$ and classify the finite groups with this property in terms of composition factors.","PeriodicalId":8427,"journal":{"name":"arXiv: Group Theory","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":"{\"title\":\"The reduction theorem for relatively maximal subgroups\",\"authors\":\"W. Guo, D. Revin, E. Vdovin\",\"doi\":\"10.1142/s1664360721500016\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Let $\\\\mathfrak{X}$ be a class of finite groups closed under taking subgroups, homomorphic images and extensions. It is known that if $A$ is a normal subgroup of a finite group $G$ then the image of an $\\\\mathfrak{X}$-maximal subgroup $H$ of $G$ in $G/A$ is not, in general, $\\\\mathfrak{X}$-maximal in $G/A$. We say that the reduction $\\\\mathfrak{X}$-theorem holds for a finite group $A$ if, for every finite group $G$ that is an extension of $A$ (i. e. contains $A$ as a normal subgroup), the number of conjugacy classes of $\\\\mathfrak{X}$-maximal subgroups in $G$ and $G/A$ is the same. The reduction $\\\\mathfrak{X}$-theorem for $A$ implies that $HA/A$ is $\\\\mathfrak{X}$-maximal in $G/A$ for every extension $G$ of $A$ and every $\\\\mathfrak{X}$-maximal subgroup $H$ of $G$. In this paper, we prove that the reduction $\\\\mathfrak{X}$-theorem holds for $A$ if and only if all $\\\\mathfrak{X}$-maximal subgroups are conjugate in $A$ and classify the finite groups with this property in terms of composition factors.\",\"PeriodicalId\":8427,\"journal\":{\"name\":\"arXiv: Group Theory\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2018-08-30\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv: Group Theory\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1142/s1664360721500016\",\"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: Group Theory","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1142/s1664360721500016","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 2
摘要
设$\mathfrak{X}$是一类闭于取子群、同态象和扩展的有限群。已知如果$A$是有限群$G$的正规子群,则$G$在$G/A$中的$\mathfrak{X}$-极大子群$H$的像一般不是$G/A$中的$\mathfrak{X}$-极大子群$H$。我们说$\mathfrak{X}$-定理对于有限群$ a $成立,如果对于$ a $的扩展(即包含$ a $作为正规子群)的每一个有限群$G$, $G$和$G/ a $中$\mathfrak{X}$-极大子群的共轭类的个数相同。$A$的约简$ mathfrak{X}$定理表明$HA/A$对于$A$的每一个扩展$G$和$G$的每一个$\mathfrak{X}$极大子群$H$,在$G/A$中是$\mathfrak{X}$最大的。本文证明了$\mathfrak{X}$-约简定理对$A$成立当且仅当$\mathfrak{X}$-极大子群在$A$中是共轭的,并根据组合因子对具有此性质的有限群进行了分类。
The reduction theorem for relatively maximal subgroups
Let $\mathfrak{X}$ be a class of finite groups closed under taking subgroups, homomorphic images and extensions. It is known that if $A$ is a normal subgroup of a finite group $G$ then the image of an $\mathfrak{X}$-maximal subgroup $H$ of $G$ in $G/A$ is not, in general, $\mathfrak{X}$-maximal in $G/A$. We say that the reduction $\mathfrak{X}$-theorem holds for a finite group $A$ if, for every finite group $G$ that is an extension of $A$ (i. e. contains $A$ as a normal subgroup), the number of conjugacy classes of $\mathfrak{X}$-maximal subgroups in $G$ and $G/A$ is the same. The reduction $\mathfrak{X}$-theorem for $A$ implies that $HA/A$ is $\mathfrak{X}$-maximal in $G/A$ for every extension $G$ of $A$ and every $\mathfrak{X}$-maximal subgroup $H$ of $G$. In this paper, we prove that the reduction $\mathfrak{X}$-theorem holds for $A$ if and only if all $\mathfrak{X}$-maximal subgroups are conjugate in $A$ and classify the finite groups with this property in terms of composition factors.