proposition: Lemma quotient_pseries2 pi1 pi2 gT (G : {group gT}) : 'O_{pi1, pi2}(G) / 'O_pi1(G) = 'O_pi2(G / 'O_pi1(G)).
proof: Proof. by rewrite -pseries1 -quotient_pseries. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq div) mathcomp(fintype bigop finset prime fingroup morphism) mathcomp(gfunctor automorphism quotient action gproduct) mathcomp(cyclic)