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)).

Lemma opp_isometry : @isometry _ _ G G -%R.
Definition cfRes phi := Cfun 1 (cfRes_subproof phi).