proposition: Lemma sn_var : forall v, SNR (Var v).
proof: Proof. intro. apply SN_intro. intros t H. redtac. ded (is_notvar_lhs_elim hyp1 lr). decomp H. subst l. rewrite sub_fun in xl. destruct c; discr. Qed.
imports: CoLoR(ATrs SN LogicUtil VecUtil VecOrd NatUtil RelUtil ARelation Union ACap ACalls) Coq(List Sumbool)