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 exists_expand_sepcon' {A} {JA: Join A}{PA: Perm_alg A}{SA: Sep_alg A}: forall B p (q: B -> pred A), (p * exp q)%pred = (exp (fun x => p * q x))%pred.