proposition: Lemma pure_typing_contains {s t Gamma M} : contains s t -> pure_typing Gamma M s -> pure_typing Gamma M t.
proof: Proof. by move=> H /pure_typing_to_typing [?] [->] /(typing_contains H) [?] [->] /typing_to_pure_typing. Qed.
imports: List Lia Relation_Definitions Relation_Operators Operators_Properties Undecidability.SystemF.SysF Undecidability.SystemF.Autosubst.syntax Undecidability.SystemF.Autosubst.unscoped Undecidability.SystemF.Util(Facts poly_type_facts pure_term_facts term_facts typing_facts iipc2_facts) ssreflect ssrbool ssrfun