(* Lemma isLKCT_rewrite r : (forall sh sh' z P, r <> YES sh sh' (LK z) P /\ r <> YES sh sh' (CT z) P) <-> ~isLK r /\ ~isCT r. *)
(* Lemma isLK_rewrite r : (forall (sh : Share.t) Psh (z : Z) (P : preds), r <> YES sh Psh (LK z) P) <-> ~ isLK r. *)

Lemma predat4 {phi b ofs sh R} :
app_pred (lock_inv sh (Vptr b ofs) R) phi ->
predat phi (b, Ptrofs.unsigned ofs) (approx (level phi) R).