Definition juicy_mem_resource: forall jm m', resource_at m' = resource_at (m_phi jm) ->
  {jm' | m_phi jm' = m' /\ m_dry jm' = m_dry jm}.

Lemma age1_constructive_joins_eq : forall {A} {JA: Join A}{PA: Perm_alg A}{agA: ageable A}{AgeA: Age_alg A} {phi1 phi2}, constructive_joins phi1 phi2 -> forall {phi1'}, age1 phi1 = Some phi1' -> forall {phi2'}, age1 phi2 = Some phi2' -> constructive_joins phi1' phi2'.