proposition: Lemma sub_rule_inv : forall x, sub_rule s1 (sub_rule s2 x) = x.
proof: Proof. intros [l r]. unfold sub_rule. simpl. rewrite !sub_inv. refl. hyp. hyp. Qed.
imports: CoLoR(ARelation ListNodup LogicUtil VecUtil RelUtil ListUtil SN BoolUtil EqUtil NatUtil ListMax VecOrd) Coq(Morphisms)