proposition: Lemma iipc2_ren_poly_type {Gamma t} ξ : iipc2 Gamma t -> iipc2 (map (ren_poly_type ξ) Gamma) (ren_poly_type ξ t).
proof: Proof. by move=> [?] /(typing_ren_poly_type ξ) /iipc2I. Qed.
imports: List Lia Undecidability.SystemF.SysF Undecidability.SystemF.Autosubst.syntax Undecidability.SystemF.Util(Facts poly_type_facts typing_facts) ssreflect ssrbool ssrfun