proposition: Lemma pquotient_pcore pi gT (G H : {group gT}) : H <| G -> pi.-group H -> 'O_pi(G / H) = 'O_pi(G) / H.
proof: Proof. by move=> nsHG piH; rewrite -quotient_pcore_mod pcore_modp. 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)