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 distrib_orp_sepcon {A : Type}{JA : Join A}{PA : Perm_alg A}{agA : ageable A} {AgeA : Age_alg A}: forall (P Q R : pred A), ((P || Q) * R = P * R || Q * R)%pred.