intros. apply pred_ext...
apply prop_right...
Qed.
Hint Rewrite @true_eq using (solve [immediate]) : norm.
Hint Rewrite @andp_dup : norm.

Lemma sepcon_TT {A} {NA: NatDed A}{SA: SepLog A}{CA: ClassicalSep A}:
forall (P: A), P |-- (P * TT).