Definition wk_split {A} {JA: Join A} :=
forall a b c d e : A, join a b c -> join d e c -> joins a d -> join_sub d b.

Lemma sepcon_andp_prop1 {A}{JA: Join A}{PA: Perm_alg A}{agA: ageable A}{AgeA: Age_alg A}:
forall (P: Prop) (Q R: pred A) , ((!! P && Q) * R = !! P && (Q * R))%pred.