Thompson's conjecture for the alternating group of degree $2p$ and $2p+1$

Babai, Azam ; Mahmoudifar, Ali

Czechoslovak Mathematical Journal, Tome 67 (2017) no. 4, pp. 1049-1058.

Résumé

For a finite group $G$ denote by $N(G)$ the set of conjugacy class sizes of $G$. In 1980s, J. G. Thompson posed the following conjecture: If $L$ is a finite nonabelian simple group, $G$ is a finite group with trivial center and $N(G) = N(L)$, then $G\cong L$. We prove this conjecture for an infinite class of simple groups. Let $p$ be an odd prime. We show that every finite group $G$ with the property $Z(G)=1$ and $N(G) = N(A_{i})$ is necessarily isomorphic to $A_{i}$, where $i\in \{2p,2p+1\}$.

Détail

DOI : 10.21136/CMJ.2017.0396-16

Classification : 20D05, 20D60
Keywords: finite group; conjugacy class size; simple group