intros A R xs; elim xs; simpl in |- *; auto.
Qed.
Hint Resolve monGoodR1.

(* Specifications: *)
Lemma monGoodR :
forall (A : Set) (R : Rel A) (xs bs cs : list A),
GoodR A R (xs ++ bs) -> GoodR A R (xs ++ cs ++ bs).