proposition: Lemma finite_union P Q : finite P -> finite Q -> finite (union P Q).
proof: Proof. rewrite 2!finite_eq. intros [p hp] [q hq]. rewrite hp, hq, <- of_app. apply finite_of_list. Qed.
imports: Coq(Basics Morphisms Setoid) CoLoR(ClassicUtil IotaUtil EpsilonUtil LogicUtil NatUtil FunUtil ListUtil ListNodup SetUtil BoundNat)