$A_{1}$-TYPE SUBGROUPS CONTAINING REGULAR UNIPOTENT ELEMENTS

Autor: TIMOTHY C. BURNESS, DONNA M. TESTERMAN
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Forum of Mathematics, Sigma, Vol 7 (2019)
Druh dokumentu: article
ISSN: 2050-5094
DOI: 10.1017/fms.2019.12
Popis: Let $G$ be a simple exceptional algebraic group of adjoint type over an algebraically closed field of characteristic $p>0$ and let $X=\text{PSL}_{2}(p)$ be a subgroup of $G$ containing a regular unipotent element $x$ of $G$. By a theorem of Testerman, $x$ is contained in a connected subgroup of $G$ of type $A_{1}$. In this paper we prove that with two exceptions, $X$ itself is contained in such a subgroup (the exceptions arise when $(G,p)=(E_{6},13)$ or $(E_{7},19)$). This extends earlier work of Seitz and Testerman, who established the containment under some additional conditions on $p$ and the embedding of $X$ in $G$. We discuss applications of our main result to the study of the subgroup structure of finite groups of Lie type.
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