Section BuildIsometries.
Variable (gT : finGroupType) (L G : {group gT}).
Implicit Types (phi psi xi : 'CF(L)) (R S : seq 'CF(L)).
Implicit Types (U : {pred 'CF(L)}) (W : {pred 'CF(G)}).
Definition cfRes phi := Cfun 1 (cfRes_subproof phi).

Lemma cfResE phi : A \subset B -> {in A, cfRes phi =1 phi}.