Definition juicy_mem_core (j: juicy_mem) : rmap := core (m_phi j).

Lemma preds_fmap_NoneP_approx: forall pp lev1 lev2, preds_fmap (approx lev1) (approx lev1) pp = NoneP -> preds_fmap (approx lev2) (approx lev2) pp = NoneP.