proposition: Lemma wf_unproj42 : forall (R:binary A2), wf R -> wf (unproj42 A1 A3 A4 R).
proof: Proof. Proof using. intros R H [[[x1 x2] x3] x4]. gen x1 x3 x4. induction_wf IH: H x2. constructor. intros [[[y1 y2] y3] y4]. auto. Qed.
imports: TLC(LibTactics LibLogic LibProd LibSum LibRelation LibNat LibInt)