proposition: Lemma iipc2_poly_arrI {Gamma s t} : iipc2 (s :: Gamma) t -> iipc2 Gamma (poly_arr s t).
proof: Proof. move=> [?] /typing_abs ?. eexists. by eassumption. Qed.
imports: List Lia Undecidability.SystemF.SysF Undecidability.SystemF.Autosubst.syntax Undecidability.SystemF.Util(Facts poly_type_facts typing_facts) ssreflect ssrbool ssrfun