具有小循环点稳定子的传递群的交集密度

IF 1 3区 数学 Q1 MATHEMATICS
Ademir Hujdurović , István Kovács , Klavdija Kutnar , Dragan Marušič
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引用次数: 0

摘要

对于作用于集合 V 的置换群 G,如果每一对元素 g、h∈F 都存在 v∈V,使得 g(v)=h(v) ,则称 G 的子集 F 为交集。跨正交置换群 G 的交集密度 ρ(G) 是商 |F|/|Gv| 的最大值,其中 Gv 是点 v∈V 的稳定子,而 F 遍历 G 中的所有交集。如果 Gv 是 G 中的最大交集,则称 G 具有厄尔多斯-科-拉多(EKR)属性。本文致力于研究具有素阶点稳定器的传递置换群,特别强调不具有 EKR 属性的 2 阶和 3 阶。除其他外,本文还给出了具有交集密度为 4/3 的 3 阶点稳定器的传递置换群无穷族的构造,以及具有任意大交集密度的 3 阶点稳定器的传递置换群无穷族的构造。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Intersection density of transitive groups with small cyclic point stabilizers
For a permutation group G acting on a set V, a subset F of G is said to be an intersecting set if for every pair of elements g,hF there exists vV such that g(v)=h(v). The intersection density ρ(G) of a transitive permutation group G is the maximum value of the quotient |F|/|Gv| where Gv is a stabilizer of a point vV and F runs over all intersecting sets in G. If Gv is a largest intersecting set in G then G is said to have the Erdős-Ko-Rado (EKR)-property. This paper is devoted to the study of transitive permutation groups, with point stabilizers of prime order with a special emphasis given to orders 2 and 3, which do not have the EKR-property. Among others, constructions of an infinite family of transitive permutation groups having point stabilizer of order 3 with intersection density 4/3 and of infinite families of transitive permutation groups having point stabilizer of order 3 with arbitrarily large intersection density are given.
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来源期刊
CiteScore
2.10
自引率
10.00%
发文量
124
审稿时长
4-8 weeks
期刊介绍: The European Journal of Combinatorics is a high standard, international, bimonthly journal of pure mathematics, specializing in theories arising from combinatorial problems. The journal is primarily open to papers dealing with mathematical structures within combinatorics and/or establishing direct links between combinatorics and other branches of mathematics and the theories of computing. The journal includes full-length research papers on important topics.
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