intros.
apply pred_ext.
apply andp_left1...
apply andp_right...
Qed.

(* Specifications: *)
Lemma TT_prop_right {A}{ND: NatDed A}: forall P: Prop,
P -> @derives A ND TT (prop P).
Lemma sepcon_andp_prop'  {A}{NA: NatDed A}{SA: SepLog A}:
forall (P:A)  (Q:Prop) (R: A), (!!Q && P)*R = !!Q&&(P*R).