proposition: Lemma cfIsom_iso rT G (R : {group rT}) (f : {morphism G >-> rT}) : forall isoG : isom G R f, isometry (cfIsom isoG).
proof: Proof. move=> isoG phi psi; rewrite unlock cfMorph_iso //; set G1 := _ @* R. by rewrite -(isom_im (isom_sym isoG)) -/G1 in phi psi *; rewrite !cfRes_id. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div choice fintype tuple finfun bigop prime order) mathcomp(ssralg poly finset fingroup morphism perm) mathcomp(automorphism quotient finalg action gproduct) mathcomp(zmodp commutator cyclic center pgroup sylow) mathcomp(matrix vector falgebra ssrnum algC algnum) mathcomp(archimedean)