组合数学系列报告——On EKR-type problems for permutation groups

报告人：谢贻林（南方科技大学）

时间：2025年3月7日，10:00-11:00

地点：海纳苑2幢820

摘要：Let G be a transitive permutation group on Omega, a subset S of G is intersecting if for any two elements s_1,s_2 in S, there exists an w in Omega such that w^{s_1}=w^{s_2}, or equivalently s_1s_2^{-1} in G_w for some w in Omega. An intersecting subset S is maximum if S has the maximal size among all intersecting subsets. The intersection density rho(G) is defined to be the ratio |S|/|G_w|, where S is a maximum intersecting subset, and G is said to have EKR-property if rho(G)=1. We define a fixer of G to be an intersecting subset of G that is also a subgroup; in particular, a fixer of G is a subgroup of G with every element fixing some point in Omega. In this talk, we will introduce our recent work in this area. We will focus on the tools we apply, such as the character tables and Hoffman's bound, the subgroups and conjugacy classes of elements in twisted rank one Lie type group.

联系人：冯涛（tfeng@zju.edu.cn）