proposition: Lemma normal_AppL_right S t: normal (AppL S t) -> normal t.
proof: Proof. induction S in t |-*; cbn; eauto using normal_app_r. Qed.
imports: List Arith Lia Morphisms FinFun Undecidability.HOU(std.std) Undecidability.HOU.calculus(prelim terms syntax semantics equivalence typing order confluence)