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

Lemma cfMorph_iso aT rT (G D : {group aT}) (f : {morphism D >-> rT}) :
G \subset D -> isometry (cfMorph : 'CF(f @* G) -> 'CF(G)).