proposition: Lemma restricted_try_add_arc_many_to_many : forall l l', incl l' l -> is_restricted R l -> is_restricted (try_add_arc_many_to_many l' l) l.
proof: Proof. induction l'; simpl; intros. hyp. apply restricted_try_add_arc_one_to_many. apply H. simpl. tauto. refl. apply IHl'. exact (incl_cons_l_incl H). hyp. Qed.
imports: Coq(Sumbool Arith) CoLoR(RelDec RelUtil ListUtil RelSub Path LogicUtil)