proposition: Lemma typingSubst_cons Delta sigma s Gamma A: Delta ⊩ sigma : Gamma -> Delta ⊢ s : A -> Delta ⊩ s .: sigma : A :: Gamma.
proof: Proof. intros ??[|]; cbn; eauto; now intros ? [= ->]. Qed.
imports: List Lia Undecidability.HOU(std.std) Undecidability.HOU.calculus(prelim terms syntax semantics)