proposition: Lemma tidy_is_simple {t} : is_simple t -> tidy t = t.
proof: Proof. elim: t; [done | by move=> ? IH1 ? IH2 /= [/IH1 -> /IH2 ->] | done]. 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