Section PROD'.
Variable A : Type.
Variable J_A: Join A.
Variable saA : Perm_alg A.
Variable B: Type.
Variable J_B: Join B.
Variable saB : Perm_alg B.
Variable agB : ageable B.
Variable asb : Age_alg B.

Lemma age_comparable {A} {JA: Join A}{PA: Perm_alg A}{SA: Sep_alg A} {agA: ageable A}{asaA: Age_alg A}:
forall phi1 phi2 phi1' phi2', age phi1 phi1' -> age phi2 phi2' ->
comparable phi1 phi2 -> comparable phi1' phi2'.