proposition: Lemma lhs_nb_args_eq_sym : forall f n (ts : Tes n) r (h : rule (apps (Fun f) ts) r), n = lhs_nb_args h.
proof: Proof. intros f n ts r h. sym. apply lhs_nb_args_eq. Qed.
imports: Coq(Morphisms Basics Lia) CoLoR(LogicUtil RelUtil VecOrd VecUtil LAlpha)