End Bigdproduct.
Section MorphIsometry.
Variable gT : finGroupType.
Implicit Types (D G H K : {group gT}) (aT rT : finGroupType).

(* Specifications: *)
Lemma cfMorph_iso aT rT (G D : {group aT}) (f : {morphism D >-> rT}) :
G \subset D -> isometry (cfMorph : 'CF(f @* G) -> 'CF(G)).
Lemma cfIsom_iso rT G (R : {group rT}) (f : {morphism G >-> rT}) :
forall isoG : isom G R f, isometry (cfIsom isoG).
Lemma cfMod_iso H G : H <| G -> isometry (@cfMod _ G H).
Lemma cfnorm_quo H G phi :
H <| G -> H \subset cfker phi -> '[phi / H] = '[phi]_G.