Hint Resolve @compareM_refl.
(* Rules for the BI connectives *)

Lemma sepcon_cut {A} {JA: Join A}{PA: Perm_alg A}{AG: ageable A}{XA: Age_alg A} : forall (P Q R S:pred A),
P |-- (Q -* R) ->
S |-- Q ->
(P * S) |-- R.