End ExtremalClass.

(* This is Aschbacher (23.4).  *)
Lemma maximal_cycle_extremal gT p (G X : {group gT}) :
p.-group G -> ~~ abelian G -> cyclic X -> X \subset G -> #|G : X| = p ->
(extremal_class G == ModularGroup) || (p == 2) && extremal2 G.