Definition initial_mem (m: mem) lev (IOK: initial_rmap_ok m lev) : juicy_mem.Definition juicy_mem_level (j: juicy_mem) (lev: nat) :=
  level (m_phi j) = lev.

Lemma perm_mem_access: forall m b ofs p, perm m b ofs Cur p -> exists p', (perm_order p' p /\ access_at m (b, ofs) Cur = Some p').