End ExtremalClass.

(* This is Aschbacher, exercise (8.4) *)
Lemma normal_rank1_structure gT p (G : {group gT}) :
p.-group G -> (forall X : {group gT}, X <| G -> abelian X -> cyclic X) ->
cyclic G \/ [&& p == 2, extremal2 G & (#|G| >= 16) || (G \isog 'Q_8)].