proposition: Lemma wf_unproj41 : forall (R:binary A1), wf R -> wf (unproj41 A2 A3 A4 R).
proof: Proof. Proof using. intros R H [[[x1 x2] x3] x4]. gen x2 x3 x4. induction_wf IH: H x1. constructor. intros [[[y1 y2] y3] y4]. auto. Qed.
imports: TLC(LibTactics LibLogic LibProd LibSum LibRelation LibNat LibInt)