Instance juicy_mem_ageable: ageable juicy_mem :=
  mkAgeable _ (fun j => level (m_phi j)) age1_juicy_mem juicy_mem_ageable_facts.

Lemma juicy_mem_ext: forall j1 j2, m_dry j1 = m_dry j2 -> m_phi j1 = m_phi j2 -> j1=j2.