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On the fixers of permutation groups

  • 演讲者:谢贻林(南科大)

  • 时间:2023-12-10 15:00-15:40

  • 地点:理学院大楼M4009

Abstract: Let G be a finite transitive permutation group on Ω, is a fixer if every element of  fixes some point in Ω. We call a fixer K large if |K|≥|G_ω|, and maximal if any proper overgroup of K is not a fixer. The study of fixers of permutation groups is related to the Erdös-Ko-Rado problem for permutation groups, derangements of permutation groups, and conjugacy classes of finite groups. We characterize large maximal fixers of primitive two-dimensional linear groups and primitive acions of simple group of twisted Lie rank 1. We will also give some examples of fixers of almost simple  groups.