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_joinx {A} {JA: Join A}{PA: Perm_alg A}{agA: ageable A}{AgeA: Age_alg A} : forall phi1 phi2 phi3 phi1' phi2' phi3', age phi1 phi1' -> age phi2 phi2' -> age phi3 phi3' -> join phi1 phi2 phi3 -> join phi1' phi2' phi3'.