Instance agB : ageable B := (ag_bij _ _ ag bijAB).

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'.