proposition: Lemma cosetpre_subcent C A : 'C_(coset H @*^-1 C)(A) \subset coset H @*^-1 'C_C(A / H).
proof: Proof. exact: morphpre_subcent. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq div) mathcomp(choice fintype prime finset fingroup morphism) mathcomp(automorphism)