proposition: Lemma wf_prod3_of_wf_2 : forall (A1 A2 A3:Type) (R1:binary A1) (R2:binary A2) (R3:binary A3), wf R2 -> wf (prod3 R1 R2 R3).
proof: Proof. Proof using. intros. apply wf_prod2_of_wf_1. apply~ wf_prod2_of_wf_2. Qed.
imports: TLC(LibTactics LibLogic LibProd LibSum LibRelation LibNat LibInt)