Let $G$ be a nontrivial transitive permutation group on a finite set $Ω$. By a classical theorem of Jordan, $G$ contains a derangement, which is an element with no fixed points on $Ω$. Given a prime divisor $r$ of $|Ω|$, we say that $G$ is $r$-elusive if it does not contain a derangement of order $r$. In a paper from 2011, Burness, Giudici and Wilson essentially reduce the classification of the $r$-elusive primitive groups to the case where $G$ is an almost simple group of Lie type. The classical groups with an $r$-elusive socle have been determined by Burness and Giudici, and in this paper we consider the analogous problem for the exceptional groups of Lie type, focussing on the special case $r=2$. Our main theorem describes all the almost simple primitive exceptional groups with a $2$-elusive socle. In other words, we determine the pairs $(G,M)$, where $G$ is an almost simple exceptional group of Lie type with socle $T$ and $M$ is a core-free maximal subgroup that intersects every conjugacy class of involutions in $T$. Our results are conclusive, with the exception of a finite list of undetermined cases for $T = E_8(q)$, which depend on the existence (or otherwise) of certain almost simple maximal subgroups of $G$ that have not yet been completely classified.
The fixed set of the inverse involution on a Lie group
在[H. Duan和S. Liu，The isomorphism type of the centralizer of an element in a李群，Journal of algebra，376（2013），25-45]，我们确定了单李群中元素的中心化子的同构类型。作为[H]的续集。Duan和S. Liu，The isomorphism type of the centralizer of an element in a李群，Journal of algebra，376（2013），25-45.]给出了计算李群上逆对合不动集同构型的一般方法。
