Definition squash (n_rm:nat * rmap') : rmap :=
    match n_rm with (n,rm) => K.squash (n, rmap'2pre_rmap rm) end.Definition unsquash (phi:rmap) : (nat * rmap') :=
    match K.unsquash phi with (n,rm) => (n, pre_rmap2rmap' rm) end.Definition rmap_level (phi:rmap) : nat := fst (unsquash phi).Definition resource_at (phi:rmap) : address -> resource := fst (snd (unsquash phi)).Infix "@" := resource_at (at level 50, no associativity).Definition ghost_of (phi:rmap) : ghost := snd (snd (unsquash phi)).

Lemma pred_ext': forall {A} `{agA: ageable A} P Q, (forall x, app_pred P x <-> app_pred Q x) -> P = Q.