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 constructive_age1_join {A} {JA: Join A}{PA: Perm_alg A}{agA: ageable A}{AgeA: Age_alg A} : forall x y z x' : A, join x y z -> age x x' -> { yz' : A*A | join x' (fst yz') (snd yz') /\ age y (fst yz') /\ age z (snd yz')}.