fact: Definition retype_ctx (n: nat) (Gamma : ctx) := map (fun A => if dec2 le (ord A) n then A else alpha) Gamma.
imports: List Lia Arith Init.Wf Morphisms Program.Program Undecidability.HOU(concon.conservativity calculus.calculus) Undecidability.HOU.unification(systemunification nth_order_unification)