Hint Resolve closed_wrt_tc_TT closed_wrtl_tc_TT : closed.

(* Specifications: *)
Lemma closed_wrt_andp: forall S (P Q: environ->mpred),
closed_wrt_vars S P -> closed_wrt_vars S Q ->
closed_wrt_vars S (P && Q).
Lemma closed_wrtl_andp: forall S (P Q: environ->mpred),
closed_wrt_lvars S P -> closed_wrt_lvars S Q ->
closed_wrt_lvars S (P && Q).