proposition: Lemma fold_right_add_restr2 : forall s' s i j x, NoDupA s -> NoDupA s' -> eqB i j -> ForallOrdPairs R s' -> ~ InA x s -> equivlistA s' (x::s) -> eqB (fold_right f i s') (f x (fold_right f j s)).
proof: Proof. intros s' s i j x **; apply (@fold_right_equivlistA_restr2 s' (x::s) i j); auto. Qed.
imports: List Sorted Setoid Basics Morphisms