Definition superprecise {A}  {JA: Join A}{PA: Perm_alg A}{SA: Sep_alg A} (P: pred A) :=
forall w1 w2, P w1 -> P w2 -> comparable w1 w2 -> w1=w2.

Lemma wand_exists {A} {JA: Join A}{PA: Perm_alg A}:
forall B P Q,  (EX x: B, P -* Q x) |-- (P -* EX x : B, Q x).