|-- Q ->
   P |-- RA_normal (overridePost Q R).
Proof. intros. 
  destruct R; simpl; auto.
Qed.

Fixpoint fold_right_and P0 (l: list Prop) : Prop :=
 match l with
 | nil => P0
 | b::r => b  /\ fold_right_and P0 r
 end.

Fixpoint fold_right_and_True (l: list Prop) : Prop :=
 matc

rewrite H. auto. Qed.