{"title":"关于素幂次的金字塔群","authors":"Xiaofang Gao , Martino Garonzi","doi":"10.1016/j.jpaa.2025.107868","DOIUrl":null,"url":null,"abstract":"<div><div>A Kirkman Triple System Γ is called <em>m</em>-pyramidal if there exists a subgroup <em>G</em> of the automorphism group of Γ that fixes <em>m</em> points and acts regularly on the other points. Such group <em>G</em> admits a unique conjugacy class <em>C</em> of involutions (elements of order 2) and <span><math><mo>|</mo><mi>C</mi><mo>|</mo><mo>=</mo><mi>m</mi></math></span>. We call groups with this property <em>m</em>-pyramidal. We prove that, if <em>m</em> is an odd prime power <span><math><msup><mrow><mi>p</mi></mrow><mrow><mi>k</mi></mrow></msup></math></span>, with <span><math><mi>p</mi><mo>≠</mo><mn>7</mn></math></span>, then every <em>m</em>-pyramidal group is solvable if and only if either <span><math><mi>m</mi><mo>=</mo><mn>9</mn></math></span> or <em>k</em> is odd. The primitive permutation groups play an important role in the proof. We also determine the orders of the <em>m</em>-pyramidal groups when <em>m</em> is a prime number.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 2","pages":"Article 107868"},"PeriodicalIF":0.7000,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On pyramidal groups of prime power degree\",\"authors\":\"Xiaofang Gao , Martino Garonzi\",\"doi\":\"10.1016/j.jpaa.2025.107868\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>A Kirkman Triple System Γ is called <em>m</em>-pyramidal if there exists a subgroup <em>G</em> of the automorphism group of Γ that fixes <em>m</em> points and acts regularly on the other points. Such group <em>G</em> admits a unique conjugacy class <em>C</em> of involutions (elements of order 2) and <span><math><mo>|</mo><mi>C</mi><mo>|</mo><mo>=</mo><mi>m</mi></math></span>. We call groups with this property <em>m</em>-pyramidal. We prove that, if <em>m</em> is an odd prime power <span><math><msup><mrow><mi>p</mi></mrow><mrow><mi>k</mi></mrow></msup></math></span>, with <span><math><mi>p</mi><mo>≠</mo><mn>7</mn></math></span>, then every <em>m</em>-pyramidal group is solvable if and only if either <span><math><mi>m</mi><mo>=</mo><mn>9</mn></math></span> or <em>k</em> is odd. The primitive permutation groups play an important role in the proof. We also determine the orders of the <em>m</em>-pyramidal groups when <em>m</em> is a prime number.</div></div>\",\"PeriodicalId\":54770,\"journal\":{\"name\":\"Journal of Pure and Applied Algebra\",\"volume\":\"229 2\",\"pages\":\"Article 107868\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2025-02-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Pure and Applied Algebra\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022404925000076\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Pure and Applied Algebra","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022404925000076","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
A Kirkman Triple System Γ is called m-pyramidal if there exists a subgroup G of the automorphism group of Γ that fixes m points and acts regularly on the other points. Such group G admits a unique conjugacy class C of involutions (elements of order 2) and . We call groups with this property m-pyramidal. We prove that, if m is an odd prime power , with , then every m-pyramidal group is solvable if and only if either or k is odd. The primitive permutation groups play an important role in the proof. We also determine the orders of the m-pyramidal groups when m is a prime number.
期刊介绍:
The Journal of Pure and Applied Algebra concentrates on that part of algebra likely to be of general mathematical interest: algebraic results with immediate applications, and the development of algebraic theories of sufficiently general relevance to allow for future applications.