src/HOL/Tools/ATP/atp_translate.ML
changeset 46320 0b8b73b49848
parent 46319 c248e4f1be74
child 46321 484dc68c8c89
--- a/src/HOL/Tools/ATP/atp_translate.ML	Mon Jan 23 17:40:31 2012 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,2557 +0,0 @@
-(*  Title:      HOL/Tools/ATP/atp_translate.ML
-    Author:     Fabian Immler, TU Muenchen
-    Author:     Makarius
-    Author:     Jasmin Blanchette, TU Muenchen
-
-Translation of HOL to FOL for Metis and Sledgehammer.
-*)
-
-signature ATP_TRANSLATE =
-sig
-  type ('a, 'b) ho_term = ('a, 'b) ATP_Problem.ho_term
-  type connective = ATP_Problem.connective
-  type ('a, 'b, 'c) formula = ('a, 'b, 'c) ATP_Problem.formula
-  type atp_format = ATP_Problem.atp_format
-  type formula_kind = ATP_Problem.formula_kind
-  type 'a problem = 'a ATP_Problem.problem
-
-  datatype locality =
-    General | Helper | Induction | Intro | Elim | Simp | Local | Assum | Chained
-
-  datatype polymorphism = Polymorphic | Raw_Monomorphic | Mangled_Monomorphic
-  datatype strictness = Strict | Non_Strict
-  datatype granularity = All_Vars | Positively_Naked_Vars | Ghost_Type_Arg_Vars
-  datatype type_level =
-    All_Types |
-    Noninf_Nonmono_Types of strictness * granularity |
-    Fin_Nonmono_Types of granularity |
-    Const_Arg_Types |
-    No_Types
-  type type_enc
-
-  val type_tag_idempotence : bool Config.T
-  val type_tag_arguments : bool Config.T
-  val no_lamsN : string
-  val hide_lamsN : string
-  val lam_liftingN : string
-  val combinatorsN : string
-  val hybrid_lamsN : string
-  val keep_lamsN : string
-  val schematic_var_prefix : string
-  val fixed_var_prefix : string
-  val tvar_prefix : string
-  val tfree_prefix : string
-  val const_prefix : string
-  val type_const_prefix : string
-  val class_prefix : string
-  val lam_lifted_prefix : string
-  val lam_lifted_mono_prefix : string
-  val lam_lifted_poly_prefix : string
-  val skolem_const_prefix : string
-  val old_skolem_const_prefix : string
-  val new_skolem_const_prefix : string
-  val combinator_prefix : string
-  val type_decl_prefix : string
-  val sym_decl_prefix : string
-  val guards_sym_formula_prefix : string
-  val tags_sym_formula_prefix : string
-  val fact_prefix : string
-  val conjecture_prefix : string
-  val helper_prefix : string
-  val class_rel_clause_prefix : string
-  val arity_clause_prefix : string
-  val tfree_clause_prefix : string
-  val lam_fact_prefix : string
-  val typed_helper_suffix : string
-  val untyped_helper_suffix : string
-  val type_tag_idempotence_helper_name : string
-  val predicator_name : string
-  val app_op_name : string
-  val type_guard_name : string
-  val type_tag_name : string
-  val simple_type_prefix : string
-  val prefixed_predicator_name : string
-  val prefixed_app_op_name : string
-  val prefixed_type_tag_name : string
-  val ascii_of : string -> string
-  val unascii_of : string -> string
-  val unprefix_and_unascii : string -> string -> string option
-  val proxy_table : (string * (string * (thm * (string * string)))) list
-  val proxify_const : string -> (string * string) option
-  val invert_const : string -> string
-  val unproxify_const : string -> string
-  val new_skolem_var_name_from_const : string -> string
-  val atp_irrelevant_consts : string list
-  val atp_schematic_consts_of : term -> typ list Symtab.table
-  val is_type_enc_higher_order : type_enc -> bool
-  val polymorphism_of_type_enc : type_enc -> polymorphism
-  val level_of_type_enc : type_enc -> type_level
-  val is_type_enc_quasi_sound : type_enc -> bool
-  val is_type_enc_fairly_sound : type_enc -> bool
-  val type_enc_from_string : strictness -> string -> type_enc
-  val adjust_type_enc : atp_format -> type_enc -> type_enc
-  val mk_aconns :
-    connective -> ('a, 'b, 'c) formula list -> ('a, 'b, 'c) formula
-  val unmangled_const : string -> string * (string, 'b) ho_term list
-  val unmangled_const_name : string -> string
-  val helper_table : ((string * bool) * thm list) list
-  val trans_lams_from_string :
-    Proof.context -> type_enc -> string -> term list -> term list * term list
-  val factsN : string
-  val prepare_atp_problem :
-    Proof.context -> atp_format -> formula_kind -> formula_kind -> type_enc
-    -> bool -> string -> bool -> bool -> term list -> term
-    -> ((string * locality) * term) list
-    -> string problem * string Symtab.table * (string * locality) list vector
-       * (string * term) list * int Symtab.table
-  val atp_problem_weights : string problem -> (string * real) list
-end;
-
-structure ATP_Translate : ATP_TRANSLATE =
-struct
-
-open ATP_Util
-open ATP_Problem
-
-type name = string * string
-
-val type_tag_idempotence =
-  Attrib.setup_config_bool @{binding atp_type_tag_idempotence} (K false)
-val type_tag_arguments =
-  Attrib.setup_config_bool @{binding atp_type_tag_arguments} (K false)
-
-val no_lamsN = "no_lams" (* used internally; undocumented *)
-val hide_lamsN = "hide_lams"
-val lam_liftingN = "lam_lifting"
-val combinatorsN = "combinators"
-val hybrid_lamsN = "hybrid_lams"
-val keep_lamsN = "keep_lams"
-
-(* It's still unclear whether all TFF1 implementations will support type
-   signatures such as "!>[A : $tType] : $o", with ghost type variables. *)
-val avoid_first_order_ghost_type_vars = false
-
-val bound_var_prefix = "B_"
-val all_bound_var_prefix = "BA_"
-val exist_bound_var_prefix = "BE_"
-val schematic_var_prefix = "V_"
-val fixed_var_prefix = "v_"
-val tvar_prefix = "T_"
-val tfree_prefix = "t_"
-val const_prefix = "c_"
-val type_const_prefix = "tc_"
-val simple_type_prefix = "s_"
-val class_prefix = "cl_"
-
-(* Freshness almost guaranteed! *)
-val atp_weak_prefix = "ATP:"
-
-val lam_lifted_prefix = atp_weak_prefix ^ "Lam"
-val lam_lifted_mono_prefix = lam_lifted_prefix ^ "m"
-val lam_lifted_poly_prefix = lam_lifted_prefix ^ "p"
-
-val skolem_const_prefix = "ATP" ^ Long_Name.separator ^ "Sko"
-val old_skolem_const_prefix = skolem_const_prefix ^ "o"
-val new_skolem_const_prefix = skolem_const_prefix ^ "n"
-
-val combinator_prefix = "COMB"
-
-val type_decl_prefix = "ty_"
-val sym_decl_prefix = "sy_"
-val guards_sym_formula_prefix = "gsy_"
-val tags_sym_formula_prefix = "tsy_"
-val fact_prefix = "fact_"
-val conjecture_prefix = "conj_"
-val helper_prefix = "help_"
-val class_rel_clause_prefix = "clar_"
-val arity_clause_prefix = "arity_"
-val tfree_clause_prefix = "tfree_"
-
-val lam_fact_prefix = "ATP.lambda_"
-val typed_helper_suffix = "_T"
-val untyped_helper_suffix = "_U"
-val type_tag_idempotence_helper_name = helper_prefix ^ "ti_idem"
-
-val predicator_name = "pp"
-val app_op_name = "aa"
-val type_guard_name = "gg"
-val type_tag_name = "tt"
-
-val prefixed_predicator_name = const_prefix ^ predicator_name
-val prefixed_app_op_name = const_prefix ^ app_op_name
-val prefixed_type_tag_name = const_prefix ^ type_tag_name
-
-(*Escaping of special characters.
-  Alphanumeric characters are left unchanged.
-  The character _ goes to __
-  Characters in the range ASCII space to / go to _A to _P, respectively.
-  Other characters go to _nnn where nnn is the decimal ASCII code.*)
-val upper_a_minus_space = Char.ord #"A" - Char.ord #" "
-
-fun stringN_of_int 0 _ = ""
-  | stringN_of_int k n =
-    stringN_of_int (k - 1) (n div 10) ^ string_of_int (n mod 10)
-
-fun ascii_of_char c =
-  if Char.isAlphaNum c then
-    String.str c
-  else if c = #"_" then
-    "__"
-  else if #" " <= c andalso c <= #"/" then
-    "_" ^ String.str (Char.chr (Char.ord c + upper_a_minus_space))
-  else
-    (* fixed width, in case more digits follow *)
-    "_" ^ stringN_of_int 3 (Char.ord c)
-
-val ascii_of = String.translate ascii_of_char
-
-(** Remove ASCII armoring from names in proof files **)
-
-(* We don't raise error exceptions because this code can run inside a worker
-   thread. Also, the errors are impossible. *)
-val unascii_of =
-  let
-    fun un rcs [] = String.implode(rev rcs)
-      | un rcs [#"_"] = un (#"_" :: rcs) [] (* ERROR *)
-        (* Three types of _ escapes: __, _A to _P, _nnn *)
-      | un rcs (#"_" :: #"_" :: cs) = un (#"_" :: rcs) cs
-      | un rcs (#"_" :: c :: cs) =
-        if #"A" <= c andalso c<= #"P" then
-          (* translation of #" " to #"/" *)
-          un (Char.chr (Char.ord c - upper_a_minus_space) :: rcs) cs
-        else
-          let val digits = List.take (c :: cs, 3) handle General.Subscript => [] in
-            case Int.fromString (String.implode digits) of
-              SOME n => un (Char.chr n :: rcs) (List.drop (cs, 2))
-            | NONE => un (c :: #"_" :: rcs) cs (* ERROR *)
-          end
-      | un rcs (c :: cs) = un (c :: rcs) cs
-  in un [] o String.explode end
-
-(* If string s has the prefix s1, return the result of deleting it,
-   un-ASCII'd. *)
-fun unprefix_and_unascii s1 s =
-  if String.isPrefix s1 s then
-    SOME (unascii_of (String.extract (s, size s1, NONE)))
-  else
-    NONE
-
-val proxy_table =
-  [("c_False", (@{const_name False}, (@{thm fFalse_def},
-       ("fFalse", @{const_name ATP.fFalse})))),
-   ("c_True", (@{const_name True}, (@{thm fTrue_def},
-       ("fTrue", @{const_name ATP.fTrue})))),
-   ("c_Not", (@{const_name Not}, (@{thm fNot_def},
-       ("fNot", @{const_name ATP.fNot})))),
-   ("c_conj", (@{const_name conj}, (@{thm fconj_def},
-       ("fconj", @{const_name ATP.fconj})))),
-   ("c_disj", (@{const_name disj}, (@{thm fdisj_def},
-       ("fdisj", @{const_name ATP.fdisj})))),
-   ("c_implies", (@{const_name implies}, (@{thm fimplies_def},
-       ("fimplies", @{const_name ATP.fimplies})))),
-   ("equal", (@{const_name HOL.eq}, (@{thm fequal_def},
-       ("fequal", @{const_name ATP.fequal})))),
-   ("c_All", (@{const_name All}, (@{thm fAll_def},
-       ("fAll", @{const_name ATP.fAll})))),
-   ("c_Ex", (@{const_name Ex}, (@{thm fEx_def},
-       ("fEx", @{const_name ATP.fEx}))))]
-
-val proxify_const = AList.lookup (op =) proxy_table #> Option.map (snd o snd)
-
-(* Readable names for the more common symbolic functions. Do not mess with the
-   table unless you know what you are doing. *)
-val const_trans_table =
-  [(@{type_name Product_Type.prod}, "prod"),
-   (@{type_name Sum_Type.sum}, "sum"),
-   (@{const_name False}, "False"),
-   (@{const_name True}, "True"),
-   (@{const_name Not}, "Not"),
-   (@{const_name conj}, "conj"),
-   (@{const_name disj}, "disj"),
-   (@{const_name implies}, "implies"),
-   (@{const_name HOL.eq}, "equal"),
-   (@{const_name All}, "All"),
-   (@{const_name Ex}, "Ex"),
-   (@{const_name If}, "If"),
-   (@{const_name Set.member}, "member"),
-   (@{const_name Meson.COMBI}, combinator_prefix ^ "I"),
-   (@{const_name Meson.COMBK}, combinator_prefix ^ "K"),
-   (@{const_name Meson.COMBB}, combinator_prefix ^ "B"),
-   (@{const_name Meson.COMBC}, combinator_prefix ^ "C"),
-   (@{const_name Meson.COMBS}, combinator_prefix ^ "S")]
-  |> Symtab.make
-  |> fold (Symtab.update o swap o snd o snd o snd) proxy_table
-
-(* Invert the table of translations between Isabelle and ATPs. *)
-val const_trans_table_inv =
-  const_trans_table |> Symtab.dest |> map swap |> Symtab.make
-val const_trans_table_unprox =
-  Symtab.empty
-  |> fold (fn (_, (isa, (_, (_, atp)))) => Symtab.update (atp, isa)) proxy_table
-
-val invert_const = perhaps (Symtab.lookup const_trans_table_inv)
-val unproxify_const = perhaps (Symtab.lookup const_trans_table_unprox)
-
-fun lookup_const c =
-  case Symtab.lookup const_trans_table c of
-    SOME c' => c'
-  | NONE => ascii_of c
-
-fun ascii_of_indexname (v, 0) = ascii_of v
-  | ascii_of_indexname (v, i) = ascii_of v ^ "_" ^ string_of_int i
-
-fun make_bound_var x = bound_var_prefix ^ ascii_of x
-fun make_all_bound_var x = all_bound_var_prefix ^ ascii_of x
-fun make_exist_bound_var x = exist_bound_var_prefix ^ ascii_of x
-fun make_schematic_var v = schematic_var_prefix ^ ascii_of_indexname v
-fun make_fixed_var x = fixed_var_prefix ^ ascii_of x
-
-fun make_schematic_type_var (x, i) =
-  tvar_prefix ^ (ascii_of_indexname (unprefix "'" x, i))
-fun make_fixed_type_var x = tfree_prefix ^ (ascii_of (unprefix "'" x))
-
-(* "HOL.eq" and choice are mapped to the ATP's equivalents *)
-local
-  val choice_const = (fst o dest_Const o HOLogic.choice_const) Term.dummyT
-  fun default c = const_prefix ^ lookup_const c
-in
-  fun make_fixed_const _ @{const_name HOL.eq} = tptp_old_equal
-    | make_fixed_const (SOME (THF (_, _, THF_With_Choice))) c =
-      if c = choice_const then tptp_choice else default c
-    | make_fixed_const _ c = default c
-end
-
-fun make_fixed_type_const c = type_const_prefix ^ lookup_const c
-
-fun make_type_class clas = class_prefix ^ ascii_of clas
-
-fun new_skolem_var_name_from_const s =
-  let val ss = s |> space_explode Long_Name.separator in
-    nth ss (length ss - 2)
-  end
-
-(* These are either simplified away by "Meson.presimplify" (most of the time) or
-   handled specially via "fFalse", "fTrue", ..., "fequal". *)
-val atp_irrelevant_consts =
-  [@{const_name False}, @{const_name True}, @{const_name Not},
-   @{const_name conj}, @{const_name disj}, @{const_name implies},
-   @{const_name HOL.eq}, @{const_name If}, @{const_name Let}]
-
-val atp_monomorph_bad_consts =
-  atp_irrelevant_consts @
-  (* These are ignored anyway by the relevance filter (unless they appear in
-     higher-order places) but not by the monomorphizer. *)
-  [@{const_name all}, @{const_name "==>"}, @{const_name "=="},
-   @{const_name Trueprop}, @{const_name All}, @{const_name Ex},
-   @{const_name Ex1}, @{const_name Ball}, @{const_name Bex}]
-
-fun add_schematic_const (x as (_, T)) =
-  Monomorph.typ_has_tvars T ? Symtab.insert_list (op =) x
-val add_schematic_consts_of =
-  Term.fold_aterms (fn Const (x as (s, _)) =>
-                       not (member (op =) atp_monomorph_bad_consts s)
-                       ? add_schematic_const x
-                      | _ => I)
-fun atp_schematic_consts_of t = add_schematic_consts_of t Symtab.empty
-
-(** Definitions and functions for FOL clauses and formulas for TPTP **)
-
-(** Isabelle arities **)
-
-type arity_atom = name * name * name list
-
-val type_class = the_single @{sort type}
-
-type arity_clause =
-  {name : string,
-   prem_atoms : arity_atom list,
-   concl_atom : arity_atom}
-
-fun add_prem_atom tvar =
-  fold (fn s => s <> type_class ? cons (`make_type_class s, `I tvar, []))
-
-(* Arity of type constructor "tcon :: (arg1, ..., argN) res" *)
-fun make_axiom_arity_clause (tcons, name, (cls, args)) =
-  let
-    val tvars = map (prefix tvar_prefix o string_of_int) (1 upto length args)
-    val tvars_srts = ListPair.zip (tvars, args)
-  in
-    {name = name,
-     prem_atoms = [] |> fold (uncurry add_prem_atom) tvars_srts,
-     concl_atom = (`make_type_class cls, `make_fixed_type_const tcons,
-                   tvars ~~ tvars)}
-  end
-
-fun arity_clause _ _ (_, []) = []
-  | arity_clause seen n (tcons, ("HOL.type", _) :: ars) =  (* ignore *)
-    arity_clause seen n (tcons, ars)
-  | arity_clause seen n (tcons, (ar as (class, _)) :: ars) =
-    if member (op =) seen class then
-      (* multiple arities for the same (tycon, class) pair *)
-      make_axiom_arity_clause (tcons,
-          lookup_const tcons ^ "___" ^ ascii_of class ^ "_" ^ string_of_int n,
-          ar) ::
-      arity_clause seen (n + 1) (tcons, ars)
-    else
-      make_axiom_arity_clause (tcons, lookup_const tcons ^ "___" ^
-                               ascii_of class, ar) ::
-      arity_clause (class :: seen) n (tcons, ars)
-
-fun multi_arity_clause [] = []
-  | multi_arity_clause ((tcons, ars) :: tc_arlists) =
-    arity_clause [] 1 (tcons, ars) @ multi_arity_clause tc_arlists
-
-(* Generate all pairs (tycon, class, sorts) such that tycon belongs to class in
-   theory thy provided its arguments have the corresponding sorts. *)
-fun type_class_pairs thy tycons classes =
-  let
-    val alg = Sign.classes_of thy
-    fun domain_sorts tycon = Sorts.mg_domain alg tycon o single
-    fun add_class tycon class =
-      cons (class, domain_sorts tycon class)
-      handle Sorts.CLASS_ERROR _ => I
-    fun try_classes tycon = (tycon, fold (add_class tycon) classes [])
-  in map try_classes tycons end
-
-(*Proving one (tycon, class) membership may require proving others, so iterate.*)
-fun iter_type_class_pairs _ _ [] = ([], [])
-  | iter_type_class_pairs thy tycons classes =
-      let
-        fun maybe_insert_class s =
-          (s <> type_class andalso not (member (op =) classes s))
-          ? insert (op =) s
-        val cpairs = type_class_pairs thy tycons classes
-        val newclasses =
-          [] |> fold (fold (fold (fold maybe_insert_class) o snd) o snd) cpairs
-        val (classes', cpairs') = iter_type_class_pairs thy tycons newclasses
-      in (classes' @ classes, union (op =) cpairs' cpairs) end
-
-fun make_arity_clauses thy tycons =
-  iter_type_class_pairs thy tycons ##> multi_arity_clause
-
-
-(** Isabelle class relations **)
-
-type class_rel_clause =
-  {name : string,
-   subclass : name,
-   superclass : name}
-
-(* Generate all pairs (sub, super) such that sub is a proper subclass of super
-   in theory "thy". *)
-fun class_pairs _ [] _ = []
-  | class_pairs thy subs supers =
-      let
-        val class_less = Sorts.class_less (Sign.classes_of thy)
-        fun add_super sub super = class_less (sub, super) ? cons (sub, super)
-        fun add_supers sub = fold (add_super sub) supers
-      in fold add_supers subs [] end
-
-fun make_class_rel_clause (sub, super) =
-  {name = sub ^ "_" ^ super, subclass = `make_type_class sub,
-   superclass = `make_type_class super}
-
-fun make_class_rel_clauses thy subs supers =
-  map make_class_rel_clause (class_pairs thy subs supers)
-
-(* intermediate terms *)
-datatype iterm =
-  IConst of name * typ * typ list |
-  IVar of name * typ |
-  IApp of iterm * iterm |
-  IAbs of (name * typ) * iterm
-
-fun ityp_of (IConst (_, T, _)) = T
-  | ityp_of (IVar (_, T)) = T
-  | ityp_of (IApp (t1, _)) = snd (dest_funT (ityp_of t1))
-  | ityp_of (IAbs ((_, T), tm)) = T --> ityp_of tm
-
-(*gets the head of a combinator application, along with the list of arguments*)
-fun strip_iterm_comb u =
-  let
-    fun stripc (IApp (t, u), ts) = stripc (t, u :: ts)
-      | stripc x = x
-  in stripc (u, []) end
-
-fun atomic_types_of T = fold_atyps (insert (op =)) T []
-
-val tvar_a_str = "'a"
-val tvar_a = TVar ((tvar_a_str, 0), HOLogic.typeS)
-val tvar_a_name = (make_schematic_type_var (tvar_a_str, 0), tvar_a_str)
-val itself_name = `make_fixed_type_const @{type_name itself}
-val TYPE_name = `(make_fixed_const NONE) @{const_name TYPE}
-val tvar_a_atype = AType (tvar_a_name, [])
-val a_itself_atype = AType (itself_name, [tvar_a_atype])
-
-fun new_skolem_const_name s num_T_args =
-  [new_skolem_const_prefix, s, string_of_int num_T_args]
-  |> space_implode Long_Name.separator
-
-fun robust_const_type thy s =
-  if s = app_op_name then
-    Logic.varifyT_global @{typ "('a => 'b) => 'a => 'b"}
-  else if String.isPrefix lam_lifted_prefix s then
-    Logic.varifyT_global @{typ "'a => 'b"}
-  else
-    (* Old Skolems throw a "TYPE" exception here, which will be caught. *)
-    s |> Sign.the_const_type thy
-
-(* This function only makes sense if "T" is as general as possible. *)
-fun robust_const_typargs thy (s, T) =
-  if s = app_op_name then
-    let val (T1, T2) = T |> domain_type |> dest_funT in [T1, T2] end
-  else if String.isPrefix old_skolem_const_prefix s then
-    [] |> Term.add_tvarsT T |> rev |> map TVar
-  else if String.isPrefix lam_lifted_prefix s then
-    if String.isPrefix lam_lifted_poly_prefix s then
-      let val (T1, T2) = T |> dest_funT in [T1, T2] end
-    else
-      []
-  else
-    (s, T) |> Sign.const_typargs thy
-
-(* Converts an Isabelle/HOL term (with combinators) into an intermediate term.
-   Also accumulates sort infomation. *)
-fun iterm_from_term thy format bs (P $ Q) =
-    let
-      val (P', P_atomics_Ts) = iterm_from_term thy format bs P
-      val (Q', Q_atomics_Ts) = iterm_from_term thy format bs Q
-    in (IApp (P', Q'), union (op =) P_atomics_Ts Q_atomics_Ts) end
-  | iterm_from_term thy format _ (Const (c, T)) =
-    (IConst (`(make_fixed_const (SOME format)) c, T,
-             robust_const_typargs thy (c, T)),
-     atomic_types_of T)
-  | iterm_from_term _ _ _ (Free (s, T)) =
-    (IConst (`make_fixed_var s, T, []), atomic_types_of T)
-  | iterm_from_term _ format _ (Var (v as (s, _), T)) =
-    (if String.isPrefix Meson_Clausify.new_skolem_var_prefix s then
-       let
-         val Ts = T |> strip_type |> swap |> op ::
-         val s' = new_skolem_const_name s (length Ts)
-       in IConst (`(make_fixed_const (SOME format)) s', T, Ts) end
-     else
-       IVar ((make_schematic_var v, s), T), atomic_types_of T)
-  | iterm_from_term _ _ bs (Bound j) =
-    nth bs j |> (fn (_, (name, T)) => (IConst (name, T, []), atomic_types_of T))
-  | iterm_from_term thy format bs (Abs (s, T, t)) =
-    let
-      fun vary s = s |> AList.defined (op =) bs s ? vary o Symbol.bump_string
-      val s = vary s
-      val name = `make_bound_var s
-      val (tm, atomic_Ts) = iterm_from_term thy format ((s, (name, T)) :: bs) t
-    in (IAbs ((name, T), tm), union (op =) atomic_Ts (atomic_types_of T)) end
-
-datatype locality =
-  General | Helper | Induction | Intro | Elim | Simp | Local | Assum | Chained
-
-datatype order = First_Order | Higher_Order
-datatype polymorphism = Polymorphic | Raw_Monomorphic | Mangled_Monomorphic
-datatype strictness = Strict | Non_Strict
-datatype granularity = All_Vars | Positively_Naked_Vars | Ghost_Type_Arg_Vars
-datatype type_level =
-  All_Types |
-  Noninf_Nonmono_Types of strictness * granularity |
-  Fin_Nonmono_Types of granularity |
-  Const_Arg_Types |
-  No_Types
-
-datatype type_enc =
-  Simple_Types of order * polymorphism * type_level |
-  Guards of polymorphism * type_level |
-  Tags of polymorphism * type_level
-
-fun is_type_enc_higher_order (Simple_Types (Higher_Order, _, _)) = true
-  | is_type_enc_higher_order _ = false
-
-fun polymorphism_of_type_enc (Simple_Types (_, poly, _)) = poly
-  | polymorphism_of_type_enc (Guards (poly, _)) = poly
-  | polymorphism_of_type_enc (Tags (poly, _)) = poly
-
-fun level_of_type_enc (Simple_Types (_, _, level)) = level
-  | level_of_type_enc (Guards (_, level)) = level
-  | level_of_type_enc (Tags (_, level)) = level
-
-fun granularity_of_type_level (Noninf_Nonmono_Types (_, grain)) = grain
-  | granularity_of_type_level (Fin_Nonmono_Types grain) = grain
-  | granularity_of_type_level _ = All_Vars
-
-fun is_type_level_quasi_sound All_Types = true
-  | is_type_level_quasi_sound (Noninf_Nonmono_Types _) = true
-  | is_type_level_quasi_sound _ = false
-val is_type_enc_quasi_sound = is_type_level_quasi_sound o level_of_type_enc
-
-fun is_type_level_fairly_sound (Fin_Nonmono_Types _) = true
-  | is_type_level_fairly_sound level = is_type_level_quasi_sound level
-val is_type_enc_fairly_sound = is_type_level_fairly_sound o level_of_type_enc
-
-fun is_type_level_monotonicity_based (Noninf_Nonmono_Types _) = true
-  | is_type_level_monotonicity_based (Fin_Nonmono_Types _) = true
-  | is_type_level_monotonicity_based _ = false
-
-(* "_query", "_bang", and "_at" are for the ASCII-challenged Metis and
-   Mirabelle. *)
-val queries = ["?", "_query"]
-val bangs = ["!", "_bang"]
-val ats = ["@", "_at"]
-
-fun try_unsuffixes ss s =
-  fold (fn s' => fn NONE => try (unsuffix s') s | some => some) ss NONE
-
-fun try_nonmono constr suffixes fallback s =
-  case try_unsuffixes suffixes s of
-    SOME s =>
-    (case try_unsuffixes suffixes s of
-       SOME s => (constr Positively_Naked_Vars, s)
-     | NONE =>
-       case try_unsuffixes ats s of
-         SOME s => (constr Ghost_Type_Arg_Vars, s)
-       | NONE => (constr All_Vars, s))
-  | NONE => fallback s
-
-fun type_enc_from_string strictness s =
-  (case try (unprefix "poly_") s of
-     SOME s => (SOME Polymorphic, s)
-   | NONE =>
-     case try (unprefix "raw_mono_") s of
-       SOME s => (SOME Raw_Monomorphic, s)
-     | NONE =>
-       case try (unprefix "mono_") s of
-         SOME s => (SOME Mangled_Monomorphic, s)
-       | NONE => (NONE, s))
-  ||> (pair All_Types
-       |> try_nonmono Fin_Nonmono_Types bangs
-       |> try_nonmono (curry Noninf_Nonmono_Types strictness) queries)
-  |> (fn (poly, (level, core)) =>
-         case (core, (poly, level)) of
-           ("simple", (SOME poly, _)) =>
-           (case (poly, level) of
-              (Polymorphic, All_Types) =>
-              Simple_Types (First_Order, Polymorphic, All_Types)
-            | (Mangled_Monomorphic, _) =>
-              if granularity_of_type_level level = All_Vars then
-                Simple_Types (First_Order, Mangled_Monomorphic, level)
-              else
-                raise Same.SAME
-            | _ => raise Same.SAME)
-         | ("simple_higher", (SOME poly, _)) =>
-           (case (poly, level) of
-              (Polymorphic, All_Types) =>
-              Simple_Types (Higher_Order, Polymorphic, All_Types)
-            | (_, Noninf_Nonmono_Types _) => raise Same.SAME
-            | (Mangled_Monomorphic, _) =>
-              if granularity_of_type_level level = All_Vars then
-                Simple_Types (Higher_Order, Mangled_Monomorphic, level)
-              else
-                raise Same.SAME
-            | _ => raise Same.SAME)
-         | ("guards", (SOME poly, _)) =>
-           if poly = Mangled_Monomorphic andalso
-              granularity_of_type_level level = Ghost_Type_Arg_Vars then
-             raise Same.SAME
-           else
-             Guards (poly, level)
-         | ("tags", (SOME poly, _)) =>
-           if granularity_of_type_level level = Ghost_Type_Arg_Vars then
-             raise Same.SAME
-           else
-             Tags (poly, level)
-         | ("args", (SOME poly, All_Types (* naja *))) =>
-           Guards (poly, Const_Arg_Types)
-         | ("erased", (NONE, All_Types (* naja *))) =>
-           Guards (Polymorphic, No_Types)
-         | _ => raise Same.SAME)
-  handle Same.SAME => error ("Unknown type encoding: " ^ quote s ^ ".")
-
-fun adjust_type_enc (THF (TPTP_Monomorphic, _, _))
-                    (Simple_Types (order, _, level)) =
-    Simple_Types (order, Mangled_Monomorphic, level)
-  | adjust_type_enc (THF _) type_enc = type_enc
-  | adjust_type_enc (TFF (TPTP_Monomorphic, _)) (Simple_Types (_, _, level)) =
-    Simple_Types (First_Order, Mangled_Monomorphic, level)
-  | adjust_type_enc (DFG DFG_Sorted) (Simple_Types (_, _, level)) =
-    Simple_Types (First_Order, Mangled_Monomorphic, level)
-  | adjust_type_enc (TFF _) (Simple_Types (_, poly, level)) =
-    Simple_Types (First_Order, poly, level)
-  | adjust_type_enc format (Simple_Types (_, poly, level)) =
-    adjust_type_enc format (Guards (poly, level))
-  | adjust_type_enc CNF_UEQ (type_enc as Guards stuff) =
-    (if is_type_enc_fairly_sound type_enc then Tags else Guards) stuff
-  | adjust_type_enc _ type_enc = type_enc
-
-fun constify_lifted (t $ u) = constify_lifted t $ constify_lifted u
-  | constify_lifted (Abs (s, T, t)) = Abs (s, T, constify_lifted t)
-  | constify_lifted (Free (x as (s, _))) =
-    (if String.isPrefix lam_lifted_prefix s then Const else Free) x
-  | constify_lifted t = t
-
-(* Requires bound variables not to clash with any schematic variables (as should
-   be the case right after lambda-lifting). *)
-fun open_form (Const (@{const_name All}, _) $ Abs (s, T, t)) =
-    let
-      val names = Name.make_context (map fst (Term.add_var_names t []))
-      val (s, _) = Name.variant s names
-    in open_form (subst_bound (Var ((s, 0), T), t)) end
-  | open_form t = t
-
-fun lift_lams_part_1 ctxt type_enc =
-  map close_form #> rpair ctxt
-  #-> Lambda_Lifting.lift_lambdas
-          (SOME ((if polymorphism_of_type_enc type_enc = Polymorphic then
-                    lam_lifted_poly_prefix
-                  else
-                    lam_lifted_mono_prefix) ^ "_a"))
-          Lambda_Lifting.is_quantifier
-  #> fst
-val lift_lams_part_2 = pairself (map (open_form o constify_lifted))
-val lift_lams = lift_lams_part_2 ooo lift_lams_part_1
-
-fun intentionalize_def (Const (@{const_name All}, _) $ Abs (_, _, t)) =
-    intentionalize_def t
-  | intentionalize_def (Const (@{const_name HOL.eq}, _) $ t $ u) =
-    let
-      fun lam T t = Abs (Name.uu, T, t)
-      val (head, args) = strip_comb t ||> rev
-      val head_T = fastype_of head
-      val n = length args
-      val arg_Ts = head_T |> binder_types |> take n |> rev
-      val u = u |> subst_atomic (args ~~ map Bound (0 upto n - 1))
-    in HOLogic.eq_const head_T $ head $ fold lam arg_Ts u end
-  | intentionalize_def t = t
-
-type translated_formula =
-  {name : string,
-   locality : locality,
-   kind : formula_kind,
-   iformula : (name, typ, iterm) formula,
-   atomic_types : typ list}
-
-fun update_iformula f ({name, locality, kind, iformula, atomic_types}
-                       : translated_formula) =
-  {name = name, locality = locality, kind = kind, iformula = f iformula,
-   atomic_types = atomic_types} : translated_formula
-
-fun fact_lift f ({iformula, ...} : translated_formula) = f iformula
-
-fun insert_type ctxt get_T x xs =
-  let val T = get_T x in
-    if exists (type_instance ctxt T o get_T) xs then xs
-    else x :: filter_out (type_generalization ctxt T o get_T) xs
-  end
-
-(* The Booleans indicate whether all type arguments should be kept. *)
-datatype type_arg_policy =
-  Explicit_Type_Args of bool (* infer_from_term_args *) |
-  Mangled_Type_Args |
-  No_Type_Args
-
-fun type_arg_policy monom_constrs type_enc s =
-  let val poly = polymorphism_of_type_enc type_enc in
-    if s = type_tag_name then
-      if poly = Mangled_Monomorphic then Mangled_Type_Args
-      else Explicit_Type_Args false
-    else case type_enc of
-      Simple_Types (_, Polymorphic, _) => Explicit_Type_Args false
-    | Tags (_, All_Types) => No_Type_Args
-    | _ =>
-      let val level = level_of_type_enc type_enc in
-        if level = No_Types orelse s = @{const_name HOL.eq} orelse
-           (s = app_op_name andalso level = Const_Arg_Types) then
-          No_Type_Args
-        else if poly = Mangled_Monomorphic then
-          Mangled_Type_Args
-        else if member (op =) monom_constrs s andalso
-                granularity_of_type_level level = Positively_Naked_Vars then
-          No_Type_Args
-        else
-          Explicit_Type_Args
-              (level = All_Types orelse
-               granularity_of_type_level level = Ghost_Type_Arg_Vars)
-      end
-  end
-
-(* Make atoms for sorted type variables. *)
-fun generic_add_sorts_on_type (_, []) = I
-  | generic_add_sorts_on_type ((x, i), s :: ss) =
-    generic_add_sorts_on_type ((x, i), ss)
-    #> (if s = the_single @{sort HOL.type} then
-          I
-        else if i = ~1 then
-          insert (op =) (`make_type_class s, `make_fixed_type_var x)
-        else
-          insert (op =) (`make_type_class s,
-                         (make_schematic_type_var (x, i), x)))
-fun add_sorts_on_tfree (TFree (s, S)) = generic_add_sorts_on_type ((s, ~1), S)
-  | add_sorts_on_tfree _ = I
-fun add_sorts_on_tvar (TVar z) = generic_add_sorts_on_type z
-  | add_sorts_on_tvar _ = I
-
-fun type_class_formula type_enc class arg =
-  AAtom (ATerm (class, arg ::
-      (case type_enc of
-         Simple_Types (First_Order, Polymorphic, _) =>
-         if avoid_first_order_ghost_type_vars then [ATerm (TYPE_name, [arg])]
-         else []
-       | _ => [])))
-fun formulas_for_types type_enc add_sorts_on_typ Ts =
-  [] |> level_of_type_enc type_enc <> No_Types ? fold add_sorts_on_typ Ts
-     |> map (fn (class, name) =>
-                type_class_formula type_enc class (ATerm (name, [])))
-
-fun mk_aconns c phis =
-  let val (phis', phi') = split_last phis in
-    fold_rev (mk_aconn c) phis' phi'
-  end
-fun mk_ahorn [] phi = phi
-  | mk_ahorn phis psi = AConn (AImplies, [mk_aconns AAnd phis, psi])
-fun mk_aquant _ [] phi = phi
-  | mk_aquant q xs (phi as AQuant (q', xs', phi')) =
-    if q = q' then AQuant (q, xs @ xs', phi') else AQuant (q, xs, phi)
-  | mk_aquant q xs phi = AQuant (q, xs, phi)
-
-fun close_universally add_term_vars phi =
-  let
-    fun add_formula_vars bounds (AQuant (_, xs, phi)) =
-        add_formula_vars (map fst xs @ bounds) phi
-      | add_formula_vars bounds (AConn (_, phis)) =
-        fold (add_formula_vars bounds) phis
-      | add_formula_vars bounds (AAtom tm) = add_term_vars bounds tm
-  in mk_aquant AForall (add_formula_vars [] phi []) phi end
-
-fun add_term_vars bounds (ATerm (name as (s, _), tms)) =
-    (if is_tptp_variable s andalso
-        not (String.isPrefix tvar_prefix s) andalso
-        not (member (op =) bounds name) then
-       insert (op =) (name, NONE)
-     else
-       I)
-    #> fold (add_term_vars bounds) tms
-  | add_term_vars bounds (AAbs ((name, _), tm)) =
-    add_term_vars (name :: bounds) tm
-fun close_formula_universally phi = close_universally add_term_vars phi
-
-fun add_iterm_vars bounds (IApp (tm1, tm2)) =
-    fold (add_iterm_vars bounds) [tm1, tm2]
-  | add_iterm_vars _ (IConst _) = I
-  | add_iterm_vars bounds (IVar (name, T)) =
-    not (member (op =) bounds name) ? insert (op =) (name, SOME T)
-  | add_iterm_vars bounds (IAbs (_, tm)) = add_iterm_vars bounds tm
-fun close_iformula_universally phi = close_universally add_iterm_vars phi
-
-val fused_infinite_type_name = @{type_name ind} (* any infinite type *)
-val fused_infinite_type = Type (fused_infinite_type_name, [])
-
-fun tvar_name (x as (s, _)) = (make_schematic_type_var x, s)
-
-fun ho_term_from_typ format type_enc =
-  let
-    fun term (Type (s, Ts)) =
-      ATerm (case (is_type_enc_higher_order type_enc, s) of
-               (true, @{type_name bool}) => `I tptp_bool_type
-             | (true, @{type_name fun}) => `I tptp_fun_type
-             | _ => if s = fused_infinite_type_name andalso
-                       is_format_typed format then
-                      `I tptp_individual_type
-                    else
-                      `make_fixed_type_const s,
-             map term Ts)
-    | term (TFree (s, _)) = ATerm (`make_fixed_type_var s, [])
-    | term (TVar (x, _)) = ATerm (tvar_name x, [])
-  in term end
-
-fun ho_term_for_type_arg format type_enc T =
-  if T = dummyT then NONE else SOME (ho_term_from_typ format type_enc T)
-
-(* This shouldn't clash with anything else. *)
-val mangled_type_sep = "\000"
-
-fun generic_mangled_type_name f (ATerm (name, [])) = f name
-  | generic_mangled_type_name f (ATerm (name, tys)) =
-    f name ^ "(" ^ space_implode "," (map (generic_mangled_type_name f) tys)
-    ^ ")"
-  | generic_mangled_type_name _ _ = raise Fail "unexpected type abstraction"
-
-fun mangled_type format type_enc =
-  generic_mangled_type_name fst o ho_term_from_typ format type_enc
-
-fun make_simple_type s =
-  if s = tptp_bool_type orelse s = tptp_fun_type orelse
-     s = tptp_individual_type then
-    s
-  else
-    simple_type_prefix ^ ascii_of s
-
-fun ho_type_from_ho_term type_enc pred_sym ary =
-  let
-    fun to_mangled_atype ty =
-      AType ((make_simple_type (generic_mangled_type_name fst ty),
-              generic_mangled_type_name snd ty), [])
-    fun to_poly_atype (ATerm (name, tys)) = AType (name, map to_poly_atype tys)
-      | to_poly_atype _ = raise Fail "unexpected type abstraction"
-    val to_atype =
-      if polymorphism_of_type_enc type_enc = Polymorphic then to_poly_atype
-      else to_mangled_atype
-    fun to_afun f1 f2 tys = AFun (f1 (hd tys), f2 (nth tys 1))
-    fun to_fo 0 ty = if pred_sym then bool_atype else to_atype ty
-      | to_fo ary (ATerm (_, tys)) = to_afun to_atype (to_fo (ary - 1)) tys
-      | to_fo _ _ = raise Fail "unexpected type abstraction"
-    fun to_ho (ty as ATerm ((s, _), tys)) =
-        if s = tptp_fun_type then to_afun to_ho to_ho tys else to_atype ty
-      | to_ho _ = raise Fail "unexpected type abstraction"
-  in if is_type_enc_higher_order type_enc then to_ho else to_fo ary end
-
-fun ho_type_from_typ format type_enc pred_sym ary =
-  ho_type_from_ho_term type_enc pred_sym ary
-  o ho_term_from_typ format type_enc
-
-fun mangled_const_name format type_enc T_args (s, s') =
-  let
-    val ty_args = T_args |> map_filter (ho_term_for_type_arg format type_enc)
-    fun type_suffix f g =
-      fold_rev (curry (op ^) o g o prefix mangled_type_sep
-                o generic_mangled_type_name f) ty_args ""
-  in (s ^ type_suffix fst ascii_of, s' ^ type_suffix snd I) end
-
-val parse_mangled_ident =
-  Scan.many1 (not o member (op =) ["(", ")", ","]) >> implode
-
-fun parse_mangled_type x =
-  (parse_mangled_ident
-   -- Scan.optional ($$ "(" |-- Scan.optional parse_mangled_types [] --| $$ ")")
-                    [] >> ATerm) x
-and parse_mangled_types x =
-  (parse_mangled_type ::: Scan.repeat ($$ "," |-- parse_mangled_type)) x
-
-fun unmangled_type s =
-  s |> suffix ")" |> raw_explode
-    |> Scan.finite Symbol.stopper
-           (Scan.error (!! (fn _ => raise Fail ("unrecognized mangled type " ^
-                                                quote s)) parse_mangled_type))
-    |> fst
-
-val unmangled_const_name = space_explode mangled_type_sep #> hd
-fun unmangled_const s =
-  let val ss = space_explode mangled_type_sep s in
-    (hd ss, map unmangled_type (tl ss))
-  end
-
-fun introduce_proxies_in_iterm type_enc =
-  let
-    fun tweak_ho_quant ho_quant T [IAbs _] = IConst (`I ho_quant, T, [])
-      | tweak_ho_quant ho_quant (T as Type (_, [p_T as Type (_, [x_T, _]), _]))
-                       _ =
-        (* Eta-expand "!!" and "??", to work around LEO-II 1.2.8 parser
-           limitation. This works in conjuction with special code in
-           "ATP_Problem" that uses the syntactic sugar "!" and "?" whenever
-           possible. *)
-        IAbs ((`I "P", p_T),
-              IApp (IConst (`I ho_quant, T, []),
-                    IAbs ((`I "X", x_T),
-                          IApp (IConst (`I "P", p_T, []),
-                                IConst (`I "X", x_T, [])))))
-      | tweak_ho_quant _ _ _ = raise Fail "unexpected type for quantifier"
-    fun intro top_level args (IApp (tm1, tm2)) =
-        IApp (intro top_level (tm2 :: args) tm1, intro false [] tm2)
-      | intro top_level args (IConst (name as (s, _), T, T_args)) =
-        (case proxify_const s of
-           SOME proxy_base =>
-           if top_level orelse is_type_enc_higher_order type_enc then
-             case (top_level, s) of
-               (_, "c_False") => IConst (`I tptp_false, T, [])
-             | (_, "c_True") => IConst (`I tptp_true, T, [])
-             | (false, "c_Not") => IConst (`I tptp_not, T, [])
-             | (false, "c_conj") => IConst (`I tptp_and, T, [])
-             | (false, "c_disj") => IConst (`I tptp_or, T, [])
-             | (false, "c_implies") => IConst (`I tptp_implies, T, [])
-             | (false, "c_All") => tweak_ho_quant tptp_ho_forall T args
-             | (false, "c_Ex") => tweak_ho_quant tptp_ho_exists T args
-             | (false, s) =>
-               if is_tptp_equal s andalso length args = 2 then
-                 IConst (`I tptp_equal, T, [])
-               else
-                 (* Use a proxy even for partially applied THF0 equality,
-                    because the LEO-II and Satallax parsers complain about not
-                    being able to infer the type of "=". *)
-                 IConst (proxy_base |>> prefix const_prefix, T, T_args)
-             | _ => IConst (name, T, [])
-           else
-             IConst (proxy_base |>> prefix const_prefix, T, T_args)
-          | NONE => if s = tptp_choice then tweak_ho_quant tptp_choice T args
-                    else IConst (name, T, T_args))
-      | intro _ _ (IAbs (bound, tm)) = IAbs (bound, intro false [] tm)
-      | intro _ _ tm = tm
-  in intro true [] end
-
-fun mangle_type_args_in_iterm format type_enc =
-  if polymorphism_of_type_enc type_enc = Mangled_Monomorphic then
-    let
-      fun mangle (IApp (tm1, tm2)) = IApp (mangle tm1, mangle tm2)
-        | mangle (tm as IConst (_, _, [])) = tm
-        | mangle (tm as IConst (name as (s, _), T, T_args)) =
-          (case unprefix_and_unascii const_prefix s of
-             NONE => tm
-           | SOME s'' =>
-             case type_arg_policy [] type_enc (invert_const s'') of
-               Mangled_Type_Args =>
-               IConst (mangled_const_name format type_enc T_args name, T, [])
-             | _ => tm)
-        | mangle (IAbs (bound, tm)) = IAbs (bound, mangle tm)
-        | mangle tm = tm
-    in mangle end
-  else
-    I
-
-fun chop_fun 0 T = ([], T)
-  | chop_fun n (Type (@{type_name fun}, [dom_T, ran_T])) =
-    chop_fun (n - 1) ran_T |>> cons dom_T
-  | chop_fun _ T = ([], T)
-
-fun filter_const_type_args _ _ _ [] = []
-  | filter_const_type_args thy s ary T_args =
-    let
-      val U = robust_const_type thy s
-      val arg_U_vars = fold Term.add_tvarsT (U |> chop_fun ary |> fst) []
-      val U_args = (s, U) |> robust_const_typargs thy
-    in
-      U_args ~~ T_args
-      |> map (fn (U, T) =>
-                 if member (op =) arg_U_vars (dest_TVar U) then dummyT else T)
-    end
-    handle TYPE _ => T_args
-
-fun filter_type_args_in_iterm thy monom_constrs type_enc =
-  let
-    fun filt ary (IApp (tm1, tm2)) = IApp (filt (ary + 1) tm1, filt 0 tm2)
-      | filt _ (tm as IConst (_, _, [])) = tm
-      | filt ary (IConst (name as (s, _), T, T_args)) =
-        (case unprefix_and_unascii const_prefix s of
-           NONE =>
-           (name,
-            if level_of_type_enc type_enc = No_Types orelse s = tptp_choice then
-              []
-            else
-              T_args)
-         | SOME s'' =>
-           let
-             val s'' = invert_const s''
-             fun filter_T_args false = T_args
-               | filter_T_args true = filter_const_type_args thy s'' ary T_args
-           in
-             case type_arg_policy monom_constrs type_enc s'' of
-               Explicit_Type_Args infer_from_term_args =>
-               (name, filter_T_args infer_from_term_args)
-             | No_Type_Args => (name, [])
-             | Mangled_Type_Args => raise Fail "unexpected (un)mangled symbol"
-           end)
-        |> (fn (name, T_args) => IConst (name, T, T_args))
-      | filt _ (IAbs (bound, tm)) = IAbs (bound, filt 0 tm)
-      | filt _ tm = tm
-  in filt 0 end
-
-fun iformula_from_prop ctxt format type_enc eq_as_iff =
-  let
-    val thy = Proof_Context.theory_of ctxt
-    fun do_term bs t atomic_Ts =
-      iterm_from_term thy format bs (Envir.eta_contract t)
-      |>> (introduce_proxies_in_iterm type_enc
-           #> mangle_type_args_in_iterm format type_enc
-           #> AAtom)
-      ||> union (op =) atomic_Ts
-    fun do_quant bs q pos s T t' =
-      let
-        val s = singleton (Name.variant_list (map fst bs)) s
-        val universal = Option.map (q = AExists ? not) pos
-        val name =
-          s |> `(case universal of
-                   SOME true => make_all_bound_var
-                 | SOME false => make_exist_bound_var
-                 | NONE => make_bound_var)
-      in
-        do_formula ((s, (name, T)) :: bs) pos t'
-        #>> mk_aquant q [(name, SOME T)]
-        ##> union (op =) (atomic_types_of T)
-      end
-    and do_conn bs c pos1 t1 pos2 t2 =
-      do_formula bs pos1 t1 ##>> do_formula bs pos2 t2 #>> uncurry (mk_aconn c)
-    and do_formula bs pos t =
-      case t of
-        @{const Trueprop} $ t1 => do_formula bs pos t1
-      | @{const Not} $ t1 => do_formula bs (Option.map not pos) t1 #>> mk_anot
-      | Const (@{const_name All}, _) $ Abs (s, T, t') =>
-        do_quant bs AForall pos s T t'
-      | (t0 as Const (@{const_name All}, _)) $ t1 =>
-        do_formula bs pos (t0 $ eta_expand (map (snd o snd) bs) t1 1)
-      | Const (@{const_name Ex}, _) $ Abs (s, T, t') =>
-        do_quant bs AExists pos s T t'
-      | (t0 as Const (@{const_name Ex}, _)) $ t1 =>
-        do_formula bs pos (t0 $ eta_expand (map (snd o snd) bs) t1 1)
-      | @{const HOL.conj} $ t1 $ t2 => do_conn bs AAnd pos t1 pos t2
-      | @{const HOL.disj} $ t1 $ t2 => do_conn bs AOr pos t1 pos t2
-      | @{const HOL.implies} $ t1 $ t2 =>
-        do_conn bs AImplies (Option.map not pos) t1 pos t2
-      | Const (@{const_name HOL.eq}, Type (_, [@{typ bool}, _])) $ t1 $ t2 =>
-        if eq_as_iff then do_conn bs AIff NONE t1 NONE t2 else do_term bs t
-      | _ => do_term bs t
-  in do_formula [] end
-
-fun presimplify_term ctxt t =
-  t |> exists_Const (member (op =) Meson.presimplified_consts o fst) t
-       ? (Skip_Proof.make_thm (Proof_Context.theory_of ctxt)
-          #> Meson.presimplify
-          #> prop_of)
-
-fun concealed_bound_name j = atp_weak_prefix ^ string_of_int j
-fun conceal_bounds Ts t =
-  subst_bounds (map (Free o apfst concealed_bound_name)
-                    (0 upto length Ts - 1 ~~ Ts), t)
-fun reveal_bounds Ts =
-  subst_atomic (map (fn (j, T) => (Free (concealed_bound_name j, T), Bound j))
-                    (0 upto length Ts - 1 ~~ Ts))
-
-fun is_fun_equality (@{const_name HOL.eq},
-                     Type (_, [Type (@{type_name fun}, _), _])) = true
-  | is_fun_equality _ = false
-
-fun extensionalize_term ctxt t =
-  if exists_Const is_fun_equality t then
-    let val thy = Proof_Context.theory_of ctxt in
-      t |> cterm_of thy |> Meson.extensionalize_conv ctxt
-        |> prop_of |> Logic.dest_equals |> snd
-    end
-  else
-    t
-
-fun simple_translate_lambdas do_lambdas ctxt t =
-  let val thy = Proof_Context.theory_of ctxt in
-    if Meson.is_fol_term thy t then
-      t
-    else
-      let
-        fun trans Ts t =
-          case t of
-            @{const Not} $ t1 => @{const Not} $ trans Ts t1
-          | (t0 as Const (@{const_name All}, _)) $ Abs (s, T, t') =>
-            t0 $ Abs (s, T, trans (T :: Ts) t')
-          | (t0 as Const (@{const_name All}, _)) $ t1 =>
-            trans Ts (t0 $ eta_expand Ts t1 1)
-          | (t0 as Const (@{const_name Ex}, _)) $ Abs (s, T, t') =>
-            t0 $ Abs (s, T, trans (T :: Ts) t')
-          | (t0 as Const (@{const_name Ex}, _)) $ t1 =>
-            trans Ts (t0 $ eta_expand Ts t1 1)
-          | (t0 as @{const HOL.conj}) $ t1 $ t2 =>
-            t0 $ trans Ts t1 $ trans Ts t2
-          | (t0 as @{const HOL.disj}) $ t1 $ t2 =>
-            t0 $ trans Ts t1 $ trans Ts t2
-          | (t0 as @{const HOL.implies}) $ t1 $ t2 =>
-            t0 $ trans Ts t1 $ trans Ts t2
-          | (t0 as Const (@{const_name HOL.eq}, Type (_, [@{typ bool}, _])))
-              $ t1 $ t2 =>
-            t0 $ trans Ts t1 $ trans Ts t2
-          | _ =>
-            if not (exists_subterm (fn Abs _ => true | _ => false) t) then t
-            else t |> Envir.eta_contract |> do_lambdas ctxt Ts
-        val (t, ctxt') = Variable.import_terms true [t] ctxt |>> the_single
-      in t |> trans [] |> singleton (Variable.export_terms ctxt' ctxt) end
-  end
-
-fun do_cheaply_conceal_lambdas Ts (t1 $ t2) =
-    do_cheaply_conceal_lambdas Ts t1
-    $ do_cheaply_conceal_lambdas Ts t2
-  | do_cheaply_conceal_lambdas Ts (Abs (_, T, t)) =
-    Const (lam_lifted_poly_prefix ^ serial_string (),
-           T --> fastype_of1 (T :: Ts, t))
-  | do_cheaply_conceal_lambdas _ t = t
-
-fun do_introduce_combinators ctxt Ts t =
-  let val thy = Proof_Context.theory_of ctxt in
-    t |> conceal_bounds Ts
-      |> cterm_of thy
-      |> Meson_Clausify.introduce_combinators_in_cterm
-      |> prop_of |> Logic.dest_equals |> snd
-      |> reveal_bounds Ts
-  end
-  (* A type variable of sort "{}" will make abstraction fail. *)
-  handle THM _ => t |> do_cheaply_conceal_lambdas Ts
-val introduce_combinators = simple_translate_lambdas do_introduce_combinators
-
-fun preprocess_abstractions_in_terms trans_lams facts =
-  let
-    val (facts, lambda_ts) =
-      facts |> map (snd o snd) |> trans_lams
-            |>> map2 (fn (name, (kind, _)) => fn t => (name, (kind, t))) facts
-    val lam_facts =
-      map2 (fn t => fn j =>
-               ((lam_fact_prefix ^ Int.toString j, Helper), (Axiom, t)))
-           lambda_ts (1 upto length lambda_ts)
-  in (facts, lam_facts) end
-
-(* Metis's use of "resolve_tac" freezes the schematic variables. We simulate the
-   same in Sledgehammer to prevent the discovery of unreplayable proofs. *)
-fun freeze_term t =
-  let
-    fun freeze (t $ u) = freeze t $ freeze u
-      | freeze (Abs (s, T, t)) = Abs (s, T, freeze t)
-      | freeze (Var ((s, i), T)) =
-        Free (atp_weak_prefix ^ s ^ "_" ^ string_of_int i, T)
-      | freeze t = t
-  in t |> exists_subterm is_Var t ? freeze end
-
-fun presimp_prop ctxt role t =
-  (let
-     val thy = Proof_Context.theory_of ctxt
-     val t = t |> Envir.beta_eta_contract
-               |> transform_elim_prop
-               |> Object_Logic.atomize_term thy
-     val need_trueprop = (fastype_of t = @{typ bool})
-   in
-     t |> need_trueprop ? HOLogic.mk_Trueprop
-       |> extensionalize_term ctxt
-       |> presimplify_term ctxt
-       |> HOLogic.dest_Trueprop
-   end
-   handle TERM _ => if role = Conjecture then @{term False} else @{term True})
-  |> pair role
-
-fun make_formula ctxt format type_enc eq_as_iff name loc kind t =
-  let
-    val (iformula, atomic_Ts) =
-      iformula_from_prop ctxt format type_enc eq_as_iff
-                         (SOME (kind <> Conjecture)) t []
-      |>> close_iformula_universally
-  in
-    {name = name, locality = loc, kind = kind, iformula = iformula,
-     atomic_types = atomic_Ts}
-  end
-
-fun make_fact ctxt format type_enc eq_as_iff ((name, loc), t) =
-  case t |> make_formula ctxt format type_enc (eq_as_iff andalso format <> CNF)
-                         name loc Axiom of
-    formula as {iformula = AAtom (IConst ((s, _), _, _)), ...} =>
-    if s = tptp_true then NONE else SOME formula
-  | formula => SOME formula
-
-fun s_not_trueprop (@{const Trueprop} $ t) = @{const Trueprop} $ s_not t
-  | s_not_trueprop t =
-    if fastype_of t = @{typ bool} then s_not t else @{prop False} (* too meta *)
-
-fun make_conjecture ctxt format type_enc =
-  map (fn ((name, loc), (kind, t)) =>
-          t |> kind = Conjecture ? s_not_trueprop
-            |> make_formula ctxt format type_enc (format <> CNF) name loc kind)
-
-(** Finite and infinite type inference **)
-
-fun tvar_footprint thy s ary =
-  (case unprefix_and_unascii const_prefix s of
-     SOME s =>
-     s |> invert_const |> robust_const_type thy |> chop_fun ary |> fst
-       |> map (fn T => Term.add_tvarsT T [] |> map fst)
-   | NONE => [])
-  handle TYPE _ => []
-
-fun ghost_type_args thy s ary =
-  if is_tptp_equal s then
-    0 upto ary - 1
-  else
-    let
-      val footprint = tvar_footprint thy s ary
-      val eq = (s = @{const_name HOL.eq})
-      fun ghosts _ [] = []
-        | ghosts seen ((i, tvars) :: args) =
-          ghosts (union (op =) seen tvars) args
-          |> (eq orelse exists (fn tvar => not (member (op =) seen tvar)) tvars)
-             ? cons i
-    in
-      if forall null footprint then
-        []
-      else
-        0 upto length footprint - 1 ~~ footprint
-        |> sort (rev_order o list_ord Term_Ord.indexname_ord o pairself snd)
-        |> ghosts []
-    end
-
-type monotonicity_info =
-  {maybe_finite_Ts : typ list,
-   surely_finite_Ts : typ list,
-   maybe_infinite_Ts : typ list,
-   surely_infinite_Ts : typ list,
-   maybe_nonmono_Ts : typ list}
-
-(* These types witness that the type classes they belong to allow infinite
-   models and hence that any types with these type classes is monotonic. *)
-val known_infinite_types =
-  [@{typ nat}, HOLogic.intT, HOLogic.realT, @{typ "nat => bool"}]
-
-fun is_type_kind_of_surely_infinite ctxt strictness cached_Ts T =
-  strictness <> Strict andalso is_type_surely_infinite ctxt true cached_Ts T
-
-(* Finite types such as "unit", "bool", "bool * bool", and "bool => bool" are
-   dangerous because their "exhaust" properties can easily lead to unsound ATP
-   proofs. On the other hand, all HOL infinite types can be given the same
-   models in first-order logic (via Löwenheim-Skolem). *)
-
-fun should_encode_type _ (_ : monotonicity_info) All_Types _ = true
-  | should_encode_type ctxt {maybe_finite_Ts, surely_infinite_Ts,
-                             maybe_nonmono_Ts, ...}
-                       (Noninf_Nonmono_Types (strictness, grain)) T =
-    grain = Ghost_Type_Arg_Vars orelse
-    (exists (type_intersect ctxt T) maybe_nonmono_Ts andalso
-     not (exists (type_instance ctxt T) surely_infinite_Ts orelse
-          (not (member (type_equiv ctxt) maybe_finite_Ts T) andalso
-           is_type_kind_of_surely_infinite ctxt strictness surely_infinite_Ts
-                                           T)))
-  | should_encode_type ctxt {surely_finite_Ts, maybe_infinite_Ts,
-                             maybe_nonmono_Ts, ...}
-                       (Fin_Nonmono_Types grain) T =
-    grain = Ghost_Type_Arg_Vars orelse
-    (exists (type_intersect ctxt T) maybe_nonmono_Ts andalso
-     (exists (type_generalization ctxt T) surely_finite_Ts orelse
-      (not (member (type_equiv ctxt) maybe_infinite_Ts T) andalso
-       is_type_surely_finite ctxt T)))
-  | should_encode_type _ _ _ _ = false
-
-fun should_guard_type ctxt mono (Guards (_, level)) should_guard_var T =
-    should_guard_var () andalso should_encode_type ctxt mono level T
-  | should_guard_type _ _ _ _ _ = false
-
-fun is_maybe_universal_var (IConst ((s, _), _, _)) =
-    String.isPrefix bound_var_prefix s orelse
-    String.isPrefix all_bound_var_prefix s
-  | is_maybe_universal_var (IVar _) = true
-  | is_maybe_universal_var _ = false
-
-datatype site =
-  Top_Level of bool option |
-  Eq_Arg of bool option |
-  Elsewhere
-
-fun should_tag_with_type _ _ _ (Top_Level _) _ _ = false
-  | should_tag_with_type ctxt mono (Tags (_, level)) site u T =
-    if granularity_of_type_level level = All_Vars then
-      should_encode_type ctxt mono level T
-    else
-      (case (site, is_maybe_universal_var u) of
-         (Eq_Arg _, true) => should_encode_type ctxt mono level T
-       | _ => false)
-  | should_tag_with_type _ _ _ _ _ _ = false
-
-fun fused_type ctxt mono level =
-  let
-    val should_encode = should_encode_type ctxt mono level
-    fun fuse 0 T = if should_encode T then T else fused_infinite_type
-      | fuse ary (Type (@{type_name fun}, [T1, T2])) =
-        fuse 0 T1 --> fuse (ary - 1) T2
-      | fuse _ _ = raise Fail "expected function type"
-  in fuse end
-
-(** predicators and application operators **)
-
-type sym_info =
-  {pred_sym : bool, min_ary : int, max_ary : int, types : typ list,
-   in_conj : bool}
-
-fun default_sym_tab_entries type_enc =
-  (make_fixed_const NONE @{const_name undefined},
-       {pred_sym = false, min_ary = 0, max_ary = 0, types = [],
-        in_conj = false}) ::
-  ([tptp_false, tptp_true]
-   |> map (rpair {pred_sym = true, min_ary = 0, max_ary = 0, types = [],
-                  in_conj = false})) @
-  ([tptp_equal, tptp_old_equal]
-   |> map (rpair {pred_sym = true, min_ary = 2, max_ary = 2, types = [],
-                  in_conj = false}))
-  |> not (is_type_enc_higher_order type_enc)
-     ? cons (prefixed_predicator_name,
-             {pred_sym = true, min_ary = 1, max_ary = 1, types = [],
-              in_conj = false})
-
-fun sym_table_for_facts ctxt type_enc explicit_apply conjs facts =
-  let
-    fun consider_var_ary const_T var_T max_ary =
-      let
-        fun iter ary T =
-          if ary = max_ary orelse type_instance ctxt var_T T orelse
-             type_instance ctxt T var_T then
-            ary
-          else
-            iter (ary + 1) (range_type T)
-      in iter 0 const_T end
-    fun add_universal_var T (accum as ((bool_vars, fun_var_Ts), sym_tab)) =
-      if explicit_apply = NONE andalso
-         (can dest_funT T orelse T = @{typ bool}) then
-        let
-          val bool_vars' = bool_vars orelse body_type T = @{typ bool}
-          fun repair_min_ary {pred_sym, min_ary, max_ary, types, in_conj} =
-            {pred_sym = pred_sym andalso not bool_vars',
-             min_ary = fold (fn T' => consider_var_ary T' T) types min_ary,
-             max_ary = max_ary, types = types, in_conj = in_conj}
-          val fun_var_Ts' =
-            fun_var_Ts |> can dest_funT T ? insert_type ctxt I T
-        in
-          if bool_vars' = bool_vars andalso
-             pointer_eq (fun_var_Ts', fun_var_Ts) then
-            accum
-          else
-            ((bool_vars', fun_var_Ts'), Symtab.map (K repair_min_ary) sym_tab)
-        end
-      else
-        accum
-    fun add_fact_syms conj_fact =
-      let
-        fun add_iterm_syms top_level tm
-                           (accum as ((bool_vars, fun_var_Ts), sym_tab)) =
-          let val (head, args) = strip_iterm_comb tm in
-            (case head of
-               IConst ((s, _), T, _) =>
-               if String.isPrefix bound_var_prefix s orelse
-                  String.isPrefix all_bound_var_prefix s then
-                 add_universal_var T accum
-               else if String.isPrefix exist_bound_var_prefix s then
-                 accum
-               else
-                 let val ary = length args in
-                   ((bool_vars, fun_var_Ts),
-                    case Symtab.lookup sym_tab s of
-                      SOME {pred_sym, min_ary, max_ary, types, in_conj} =>
-                      let
-                        val pred_sym =
-                          pred_sym andalso top_level andalso not bool_vars
-                        val types' = types |> insert_type ctxt I T
-                        val in_conj = in_conj orelse conj_fact
-                        val min_ary =
-                          if is_some explicit_apply orelse
-                             pointer_eq (types', types) then
-                            min_ary
-                          else
-                            fold (consider_var_ary T) fun_var_Ts min_ary
-                      in
-                        Symtab.update (s, {pred_sym = pred_sym,
-                                           min_ary = Int.min (ary, min_ary),
-                                           max_ary = Int.max (ary, max_ary),
-                                           types = types', in_conj = in_conj})
-                                      sym_tab
-                      end
-                    | NONE =>
-                      let
-                        val pred_sym = top_level andalso not bool_vars
-                        val min_ary =
-                          case explicit_apply of
-                            SOME true => 0
-                          | SOME false => ary
-                          | NONE => fold (consider_var_ary T) fun_var_Ts ary
-                      in
-                        Symtab.update_new (s,
-                            {pred_sym = pred_sym, min_ary = min_ary,
-                             max_ary = ary, types = [T], in_conj = conj_fact})
-                            sym_tab
-                      end)
-                 end
-             | IVar (_, T) => add_universal_var T accum
-             | IAbs ((_, T), tm) =>
-               accum |> add_universal_var T |> add_iterm_syms false tm
-             | _ => accum)
-            |> fold (add_iterm_syms false) args
-          end
-      in K (add_iterm_syms true) |> formula_fold NONE |> fact_lift end
-  in
-    ((false, []), Symtab.empty)
-    |> fold (add_fact_syms true) conjs
-    |> fold (add_fact_syms false) facts
-    |> snd
-    |> fold Symtab.update (default_sym_tab_entries type_enc)
-  end
-
-fun min_ary_of sym_tab s =
-  case Symtab.lookup sym_tab s of
-    SOME ({min_ary, ...} : sym_info) => min_ary
-  | NONE =>
-    case unprefix_and_unascii const_prefix s of
-      SOME s =>
-      let val s = s |> unmangled_const_name |> invert_const in
-        if s = predicator_name then 1
-        else if s = app_op_name then 2
-        else if s = type_guard_name then 1
-        else 0
-      end
-    | NONE => 0
-
-(* True if the constant ever appears outside of the top-level position in
-   literals, or if it appears with different arities (e.g., because of different
-   type instantiations). If false, the constant always receives all of its
-   arguments and is used as a predicate. *)
-fun is_pred_sym sym_tab s =
-  case Symtab.lookup sym_tab s of
-    SOME ({pred_sym, min_ary, max_ary, ...} : sym_info) =>
-    pred_sym andalso min_ary = max_ary
-  | NONE => false
-
-val app_op = `(make_fixed_const NONE) app_op_name
-val predicator_combconst =
-  IConst (`(make_fixed_const NONE) predicator_name, @{typ "bool => bool"}, [])
-
-fun list_app head args = fold (curry (IApp o swap)) args head
-fun predicator tm = IApp (predicator_combconst, tm)
-
-fun firstorderize_fact thy monom_constrs format type_enc sym_tab =
-  let
-    fun do_app arg head =
-      let
-        val head_T = ityp_of head
-        val (arg_T, res_T) = dest_funT head_T
-        val app =
-          IConst (app_op, head_T --> head_T, [arg_T, res_T])
-          |> mangle_type_args_in_iterm format type_enc
-      in list_app app [head, arg] end
-    fun list_app_ops head args = fold do_app args head
-    fun introduce_app_ops tm =
-      case strip_iterm_comb tm of
-        (head as IConst ((s, _), _, _), args) =>
-        args |> map introduce_app_ops
-             |> chop (min_ary_of sym_tab s)
-             |>> list_app head
-             |-> list_app_ops
-      | (head, args) => list_app_ops head (map introduce_app_ops args)
-    fun introduce_predicators tm =
-      case strip_iterm_comb tm of
-        (IConst ((s, _), _, _), _) =>
-        if is_pred_sym sym_tab s then tm else predicator tm
-      | _ => predicator tm
-    val do_iterm =
-      not (is_type_enc_higher_order type_enc)
-      ? (introduce_app_ops #> introduce_predicators)
-      #> filter_type_args_in_iterm thy monom_constrs type_enc
-  in update_iformula (formula_map do_iterm) end
-
-(** Helper facts **)
-
-val not_ffalse = @{lemma "~ fFalse" by (unfold fFalse_def) fast}
-val ftrue = @{lemma "fTrue" by (unfold fTrue_def) fast}
-
-(* The Boolean indicates that a fairly sound type encoding is needed. *)
-val helper_table =
-  [(("COMBI", false), @{thms Meson.COMBI_def}),
-   (("COMBK", false), @{thms Meson.COMBK_def}),
-   (("COMBB", false), @{thms Meson.COMBB_def}),
-   (("COMBC", false), @{thms Meson.COMBC_def}),
-   (("COMBS", false), @{thms Meson.COMBS_def}),
-   ((predicator_name, false), [not_ffalse, ftrue]),
-   (("fFalse", false), [not_ffalse]),
-   (("fFalse", true), @{thms True_or_False}),
-   (("fTrue", false), [ftrue]),
-   (("fTrue", true), @{thms True_or_False}),
-   (("fNot", false),
-    @{thms fNot_def [THEN Meson.iff_to_disjD, THEN conjunct1]
-           fNot_def [THEN Meson.iff_to_disjD, THEN conjunct2]}),
-   (("fconj", false),
-    @{lemma "~ P | ~ Q | fconj P Q" "~ fconj P Q | P" "~ fconj P Q | Q"
-        by (unfold fconj_def) fast+}),
-   (("fdisj", false),
-    @{lemma "~ P | fdisj P Q" "~ Q | fdisj P Q" "~ fdisj P Q | P | Q"
-        by (unfold fdisj_def) fast+}),
-   (("fimplies", false),
-    @{lemma "P | fimplies P Q" "~ Q | fimplies P Q" "~ fimplies P Q | ~ P | Q"
-        by (unfold fimplies_def) fast+}),
-   (("fequal", true),
-    (* This is a lie: Higher-order equality doesn't need a sound type encoding.
-       However, this is done so for backward compatibility: Including the
-       equality helpers by default in Metis breaks a few existing proofs. *)
-    @{thms fequal_def [THEN Meson.iff_to_disjD, THEN conjunct1]
-           fequal_def [THEN Meson.iff_to_disjD, THEN conjunct2]}),
-   (* Partial characterization of "fAll" and "fEx". A complete characterization
-      would require the axiom of choice for replay with Metis. *)
-   (("fAll", false), [@{lemma "~ fAll P | P x" by (auto simp: fAll_def)}]),
-   (("fEx", false), [@{lemma "~ P x | fEx P" by (auto simp: fEx_def)}]),
-   (("If", true), @{thms if_True if_False True_or_False})]
-  |> map (apsnd (map zero_var_indexes))
-
-fun atype_of_type_vars (Simple_Types (_, Polymorphic, _)) = SOME atype_of_types
-  | atype_of_type_vars _ = NONE
-
-fun bound_tvars type_enc sorts Ts =
-  (sorts ? mk_ahorn (formulas_for_types type_enc add_sorts_on_tvar Ts))
-  #> mk_aquant AForall
-        (map_filter (fn TVar (x as (s, _), _) =>
-                        SOME ((make_schematic_type_var x, s),
-                              atype_of_type_vars type_enc)
-                      | _ => NONE) Ts)
-
-fun eq_formula type_enc atomic_Ts pred_sym tm1 tm2 =
-  (if pred_sym then AConn (AIff, [AAtom tm1, AAtom tm2])
-   else AAtom (ATerm (`I tptp_equal, [tm1, tm2])))
-  |> close_formula_universally
-  |> bound_tvars type_enc true atomic_Ts
-
-val type_tag = `(make_fixed_const NONE) type_tag_name
-
-fun type_tag_idempotence_fact format type_enc =
-  let
-    fun var s = ATerm (`I s, [])
-    fun tag tm = ATerm (type_tag, [var "A", tm])
-    val tagged_var = tag (var "X")
-  in
-    Formula (type_tag_idempotence_helper_name, Axiom,
-             eq_formula type_enc [] false (tag tagged_var) tagged_var,
-             isabelle_info format simpN, NONE)
-  end
-
-fun should_specialize_helper type_enc t =
-  polymorphism_of_type_enc type_enc <> Polymorphic andalso
-  level_of_type_enc type_enc <> No_Types andalso
-  not (null (Term.hidden_polymorphism t))
-
-fun helper_facts_for_sym ctxt format type_enc (s, {types, ...} : sym_info) =
-  case unprefix_and_unascii const_prefix s of
-    SOME mangled_s =>
-    let
-      val thy = Proof_Context.theory_of ctxt
-      val unmangled_s = mangled_s |> unmangled_const_name
-      fun dub needs_fairly_sound j k =
-        (unmangled_s ^ "_" ^ string_of_int j ^ "_" ^ string_of_int k ^
-         (if mangled_s = unmangled_s then "" else "_" ^ ascii_of mangled_s) ^
-         (if needs_fairly_sound then typed_helper_suffix
-          else untyped_helper_suffix),
-         Helper)
-      fun dub_and_inst needs_fairly_sound (th, j) =
-        let val t = prop_of th in
-          if should_specialize_helper type_enc t then
-            map (fn T => specialize_type thy (invert_const unmangled_s, T) t)
-                types
-          else
-            [t]
-        end
-        |> map (fn (k, t) => (dub needs_fairly_sound j k, t)) o tag_list 1
-      val make_facts = map_filter (make_fact ctxt format type_enc false)
-      val fairly_sound = is_type_enc_fairly_sound type_enc
-    in
-      helper_table
-      |> maps (fn ((helper_s, needs_fairly_sound), ths) =>
-                  if helper_s <> unmangled_s orelse
-                     (needs_fairly_sound andalso not fairly_sound) then
-                    []
-                  else
-                    ths ~~ (1 upto length ths)
-                    |> maps (dub_and_inst needs_fairly_sound)
-                    |> make_facts)
-    end
-  | NONE => []
-fun helper_facts_for_sym_table ctxt format type_enc sym_tab =
-  Symtab.fold_rev (append o helper_facts_for_sym ctxt format type_enc) sym_tab
-                  []
-
-(***************************************************************)
-(* Type Classes Present in the Axiom or Conjecture Clauses     *)
-(***************************************************************)
-
-fun set_insert (x, s) = Symtab.update (x, ()) s
-
-fun add_classes (sorts, cset) = List.foldl set_insert cset (flat sorts)
-
-(* Remove this trivial type class (FIXME: similar code elsewhere) *)
-fun delete_type cset = Symtab.delete_safe (the_single @{sort HOL.type}) cset
-
-fun classes_of_terms get_Ts =
-  map (map snd o get_Ts)
-  #> List.foldl add_classes Symtab.empty
-  #> delete_type #> Symtab.keys
-
-val tfree_classes_of_terms = classes_of_terms Misc_Legacy.term_tfrees
-val tvar_classes_of_terms = classes_of_terms Misc_Legacy.term_tvars
-
-fun fold_type_constrs f (Type (s, Ts)) x =
-    fold (fold_type_constrs f) Ts (f (s, x))
-  | fold_type_constrs _ _ x = x
-
-(* Type constructors used to instantiate overloaded constants are the only ones
-   needed. *)
-fun add_type_constrs_in_term thy =
-  let
-    fun add (Const (@{const_name Meson.skolem}, _) $ _) = I
-      | add (t $ u) = add t #> add u
-      | add (Const x) =
-        x |> robust_const_typargs thy |> fold (fold_type_constrs set_insert)
-      | add (Abs (_, _, u)) = add u
-      | add _ = I
-  in add end
-
-fun type_constrs_of_terms thy ts =
-  Symtab.keys (fold (add_type_constrs_in_term thy) ts Symtab.empty)
-
-fun extract_lambda_def (Const (@{const_name HOL.eq}, _) $ t $ u) =
-    let val (head, args) = strip_comb t in
-      (head |> dest_Const |> fst,
-       fold_rev (fn t as Var ((s, _), T) =>
-                    (fn u => Abs (s, T, abstract_over (t, u)))
-                  | _ => raise Fail "expected Var") args u)
-    end
-  | extract_lambda_def _ = raise Fail "malformed lifted lambda"
-
-fun trans_lams_from_string ctxt type_enc lam_trans =
-  if lam_trans = no_lamsN then
-    rpair []
-  else if lam_trans = hide_lamsN then
-    lift_lams ctxt type_enc ##> K []
-  else if lam_trans = lam_liftingN then
-    lift_lams ctxt type_enc
-  else if lam_trans = combinatorsN then
-    map (introduce_combinators ctxt) #> rpair []
-  else if lam_trans = hybrid_lamsN then
-    lift_lams_part_1 ctxt type_enc
-    ##> maps (fn t => [t, introduce_combinators ctxt (intentionalize_def t)])
-    #> lift_lams_part_2
-  else if lam_trans = keep_lamsN then
-    map (Envir.eta_contract) #> rpair []
-  else
-    error ("Unknown lambda translation scheme: " ^ quote lam_trans ^ ".")
-
-fun translate_formulas ctxt format prem_kind type_enc lam_trans presimp hyp_ts
-                       concl_t facts =
-  let
-    val thy = Proof_Context.theory_of ctxt
-    val trans_lams = trans_lams_from_string ctxt type_enc lam_trans
-    val fact_ts = facts |> map snd
-    (* Remove existing facts from the conjecture, as this can dramatically
-       boost an ATP's performance (for some reason). *)
-    val hyp_ts =
-      hyp_ts
-      |> map (fn t => if member (op aconv) fact_ts t then @{prop True} else t)
-    val facts = facts |> map (apsnd (pair Axiom))
-    val conjs =
-      map (pair prem_kind) hyp_ts @ [(Conjecture, s_not_trueprop concl_t)]
-      |> map (apsnd freeze_term)
-      |> map2 (pair o rpair Local o string_of_int) (0 upto length hyp_ts)
-    val ((conjs, facts), lam_facts) =
-      (conjs, facts)
-      |> presimp ? pairself (map (apsnd (uncurry (presimp_prop ctxt))))
-      |> (if lam_trans = no_lamsN then
-            rpair []
-          else
-            op @
-            #> preprocess_abstractions_in_terms trans_lams
-            #>> chop (length conjs))
-    val conjs = conjs |> make_conjecture ctxt format type_enc
-    val (fact_names, facts) =
-      facts
-      |> map_filter (fn (name, (_, t)) =>
-                        make_fact ctxt format type_enc true (name, t)
-                        |> Option.map (pair name))
-      |> ListPair.unzip
-    val lifted = lam_facts |> map (extract_lambda_def o snd o snd)
-    val lam_facts =
-      lam_facts |> map_filter (make_fact ctxt format type_enc true o apsnd snd)
-    val all_ts = concl_t :: hyp_ts @ fact_ts
-    val subs = tfree_classes_of_terms all_ts
-    val supers = tvar_classes_of_terms all_ts
-    val tycons = type_constrs_of_terms thy all_ts
-    val (supers, arity_clauses) =
-      if level_of_type_enc type_enc = No_Types then ([], [])
-      else make_arity_clauses thy tycons supers
-    val class_rel_clauses = make_class_rel_clauses thy subs supers
-  in
-    (fact_names |> map single, union (op =) subs supers, conjs,
-     facts @ lam_facts, class_rel_clauses, arity_clauses, lifted)
-  end
-
-val type_guard = `(make_fixed_const NONE) type_guard_name
-
-fun type_guard_iterm format type_enc T tm =
-  IApp (IConst (type_guard, T --> @{typ bool}, [T])
-        |> mangle_type_args_in_iterm format type_enc, tm)
-
-fun is_var_positively_naked_in_term _ (SOME false) _ accum = accum
-  | is_var_positively_naked_in_term name _ (ATerm ((s, _), tms)) accum =
-    accum orelse (is_tptp_equal s andalso member (op =) tms (ATerm (name, [])))
-  | is_var_positively_naked_in_term _ _ _ _ = true
-
-fun is_var_ghost_type_arg_in_term thy polym_constrs name pos tm accum =
-  is_var_positively_naked_in_term name pos tm accum orelse
-  let
-    val var = ATerm (name, [])
-    fun is_nasty_in_term (ATerm (_, [])) = false
-      | is_nasty_in_term (ATerm ((s, _), tms)) =
-        let
-          val ary = length tms
-          val polym_constr = member (op =) polym_constrs s
-          val ghosts = ghost_type_args thy s ary
-        in
-          exists (fn (j, tm) =>
-                     if polym_constr then
-                       member (op =) ghosts j andalso
-                       (tm = var orelse is_nasty_in_term tm)
-                     else
-                       tm = var andalso member (op =) ghosts j)
-                 (0 upto ary - 1 ~~ tms)
-          orelse (not polym_constr andalso exists is_nasty_in_term tms)
-        end
-      | is_nasty_in_term _ = true
-  in is_nasty_in_term tm end
-
-fun should_guard_var_in_formula thy polym_constrs level pos phi (SOME true)
-                                name =
-    (case granularity_of_type_level level of
-       All_Vars => true
-     | Positively_Naked_Vars =>
-       formula_fold pos (is_var_positively_naked_in_term name) phi false
-     | Ghost_Type_Arg_Vars =>
-       formula_fold pos (is_var_ghost_type_arg_in_term thy polym_constrs name)
-                    phi false)
-  | should_guard_var_in_formula _ _ _ _ _ _ _ = true
-
-fun always_guard_var_in_formula _ _ _ _ _ _ _ = true
-
-fun should_generate_tag_bound_decl _ _ _ (SOME true) _ = false
-  | should_generate_tag_bound_decl ctxt mono (Tags (_, level)) _ T =
-    granularity_of_type_level level <> All_Vars andalso
-    should_encode_type ctxt mono level T
-  | should_generate_tag_bound_decl _ _ _ _ _ = false
-
-fun mk_aterm format type_enc name T_args args =
-  ATerm (name, map_filter (ho_term_for_type_arg format type_enc) T_args @ args)
-
-fun tag_with_type ctxt format mono type_enc pos T tm =
-  IConst (type_tag, T --> T, [T])
-  |> mangle_type_args_in_iterm format type_enc
-  |> ho_term_from_iterm ctxt format mono type_enc pos
-  |> (fn ATerm (s, tms) => ATerm (s, tms @ [tm])
-       | _ => raise Fail "unexpected lambda-abstraction")
-and ho_term_from_iterm ctxt format mono type_enc =
-  let
-    fun term site u =
-      let
-        val (head, args) = strip_iterm_comb u
-        val pos =
-          case site of
-            Top_Level pos => pos
-          | Eq_Arg pos => pos
-          | _ => NONE
-        val t =
-          case head of
-            IConst (name as (s, _), _, T_args) =>
-            let
-              val arg_site = if is_tptp_equal s then Eq_Arg pos else Elsewhere
-            in
-              map (term arg_site) args |> mk_aterm format type_enc name T_args
-            end
-          | IVar (name, _) =>
-            map (term Elsewhere) args |> mk_aterm format type_enc name []
-          | IAbs ((name, T), tm) =>
-            AAbs ((name, ho_type_from_typ format type_enc true 0 T),
-                  term Elsewhere tm)
-          | IApp _ => raise Fail "impossible \"IApp\""
-        val T = ityp_of u
-      in
-        if should_tag_with_type ctxt mono type_enc site u T then
-          tag_with_type ctxt format mono type_enc pos T t
-        else
-          t
-      end
-  in term o Top_Level end
-and formula_from_iformula ctxt polym_constrs format mono type_enc
-                          should_guard_var =
-  let
-    val thy = Proof_Context.theory_of ctxt
-    val level = level_of_type_enc type_enc
-    val do_term = ho_term_from_iterm ctxt format mono type_enc
-    val do_bound_type =
-      case type_enc of
-        Simple_Types _ => fused_type ctxt mono level 0
-        #> ho_type_from_typ format type_enc false 0 #> SOME
-      | _ => K NONE
-    fun do_out_of_bound_type pos phi universal (name, T) =
-      if should_guard_type ctxt mono type_enc
-             (fn () => should_guard_var thy polym_constrs level pos phi
-                                        universal name) T then
-        IVar (name, T)
-        |> type_guard_iterm format type_enc T
-        |> do_term pos |> AAtom |> SOME
-      else if should_generate_tag_bound_decl ctxt mono type_enc universal T then
-        let
-          val var = ATerm (name, [])
-          val tagged_var = tag_with_type ctxt format mono type_enc pos T var
-        in SOME (AAtom (ATerm (`I tptp_equal, [tagged_var, var]))) end
-      else
-        NONE
-    fun do_formula pos (AQuant (q, xs, phi)) =
-        let
-          val phi = phi |> do_formula pos
-          val universal = Option.map (q = AExists ? not) pos
-        in
-          AQuant (q, xs |> map (apsnd (fn NONE => NONE
-                                        | SOME T => do_bound_type T)),
-                  (if q = AForall then mk_ahorn else fold_rev (mk_aconn AAnd))
-                      (map_filter
-                           (fn (_, NONE) => NONE
-                             | (s, SOME T) =>
-                               do_out_of_bound_type pos phi universal (s, T))
-                           xs)
-                      phi)
-        end
-      | do_formula pos (AConn conn) = aconn_map pos do_formula conn
-      | do_formula pos (AAtom tm) = AAtom (do_term pos tm)
-  in do_formula end
-
-(* Each fact is given a unique fact number to avoid name clashes (e.g., because
-   of monomorphization). The TPTP explicitly forbids name clashes, and some of
-   the remote provers might care. *)
-fun formula_line_for_fact ctxt polym_constrs format prefix encode freshen pos
-        mono type_enc (j, {name, locality, kind, iformula, atomic_types}) =
-  (prefix ^ (if freshen then string_of_int j ^ "_" else "") ^ encode name, kind,
-   iformula
-   |> formula_from_iformula ctxt polym_constrs format mono type_enc
-          should_guard_var_in_formula (if pos then SOME true else NONE)
-   |> close_formula_universally
-   |> bound_tvars type_enc true atomic_types,
-   NONE,
-   case locality of
-     Intro => isabelle_info format introN
-   | Elim => isabelle_info format elimN
-   | Simp => isabelle_info format simpN
-   | _ => NONE)
-  |> Formula
-
-fun formula_line_for_class_rel_clause format type_enc
-        ({name, subclass, superclass, ...} : class_rel_clause) =
-  let val ty_arg = ATerm (tvar_a_name, []) in
-    Formula (class_rel_clause_prefix ^ ascii_of name, Axiom,
-             AConn (AImplies,
-                    [type_class_formula type_enc subclass ty_arg,
-                     type_class_formula type_enc superclass ty_arg])
-             |> mk_aquant AForall
-                          [(tvar_a_name, atype_of_type_vars type_enc)],
-             isabelle_info format introN, NONE)
-  end
-
-fun formula_from_arity_atom type_enc (class, t, args) =
-  ATerm (t, map (fn arg => ATerm (arg, [])) args)
-  |> type_class_formula type_enc class
-
-fun formula_line_for_arity_clause format type_enc
-        ({name, prem_atoms, concl_atom} : arity_clause) =
-  Formula (arity_clause_prefix ^ name, Axiom,
-           mk_ahorn (map (formula_from_arity_atom type_enc) prem_atoms)
-                    (formula_from_arity_atom type_enc concl_atom)
-           |> mk_aquant AForall
-                  (map (rpair (atype_of_type_vars type_enc)) (#3 concl_atom)),
-           isabelle_info format introN, NONE)
-
-fun formula_line_for_conjecture ctxt polym_constrs format mono type_enc
-        ({name, kind, iformula, atomic_types, ...} : translated_formula) =
-  Formula (conjecture_prefix ^ name, kind,
-           iformula
-           |> formula_from_iformula ctxt polym_constrs format mono type_enc
-                  should_guard_var_in_formula (SOME false)
-           |> close_formula_universally
-           |> bound_tvars type_enc true atomic_types, NONE, NONE)
-
-fun formula_line_for_free_type j phi =
-  Formula (tfree_clause_prefix ^ string_of_int j, Hypothesis, phi, NONE, NONE)
-fun formula_lines_for_free_types type_enc (facts : translated_formula list) =
-  let
-    val phis =
-      fold (union (op =)) (map #atomic_types facts) []
-      |> formulas_for_types type_enc add_sorts_on_tfree
-  in map2 formula_line_for_free_type (0 upto length phis - 1) phis end
-
-(** Symbol declarations **)
-
-fun decl_line_for_class order s =
-  let val name as (s, _) = `make_type_class s in
-    Decl (sym_decl_prefix ^ s, name,
-          if order = First_Order then
-            ATyAbs ([tvar_a_name],
-                    if avoid_first_order_ghost_type_vars then
-                      AFun (a_itself_atype, bool_atype)
-                    else
-                      bool_atype)
-          else
-            AFun (atype_of_types, bool_atype))
-  end
-
-fun decl_lines_for_classes type_enc classes =
-  case type_enc of
-    Simple_Types (order, Polymorphic, _) =>
-    map (decl_line_for_class order) classes
-  | _ => []
-
-fun sym_decl_table_for_facts ctxt format type_enc sym_tab (conjs, facts) =
-  let
-    fun add_iterm_syms tm =
-      let val (head, args) = strip_iterm_comb tm in
-        (case head of
-           IConst ((s, s'), T, T_args) =>
-           let
-             val (pred_sym, in_conj) =
-               case Symtab.lookup sym_tab s of
-                 SOME ({pred_sym, in_conj, ...} : sym_info) =>
-                 (pred_sym, in_conj)
-               | NONE => (false, false)
-             val decl_sym =
-               (case type_enc of
-                  Guards _ => not pred_sym
-                | _ => true) andalso
-               is_tptp_user_symbol s
-           in
-             if decl_sym then
-               Symtab.map_default (s, [])
-                   (insert_type ctxt #3 (s', T_args, T, pred_sym, length args,
-                                         in_conj))
-             else
-               I
-           end
-         | IAbs (_, tm) => add_iterm_syms tm
-         | _ => I)
-        #> fold add_iterm_syms args
-      end
-    val add_fact_syms = K add_iterm_syms |> formula_fold NONE |> fact_lift
-    fun add_formula_var_types (AQuant (_, xs, phi)) =
-        fold (fn (_, SOME T) => insert_type ctxt I T | _ => I) xs
-        #> add_formula_var_types phi
-      | add_formula_var_types (AConn (_, phis)) =
-        fold add_formula_var_types phis
-      | add_formula_var_types _ = I
-    fun var_types () =
-      if polymorphism_of_type_enc type_enc = Polymorphic then [tvar_a]
-      else fold (fact_lift add_formula_var_types) (conjs @ facts) []
-    fun add_undefined_const T =
-      let
-        val (s, s') =
-          `(make_fixed_const NONE) @{const_name undefined}
-          |> (case type_arg_policy [] type_enc @{const_name undefined} of
-                Mangled_Type_Args => mangled_const_name format type_enc [T]
-              | _ => I)
-      in
-        Symtab.map_default (s, [])
-                           (insert_type ctxt #3 (s', [T], T, false, 0, false))
-      end
-    fun add_TYPE_const () =
-      let val (s, s') = TYPE_name in
-        Symtab.map_default (s, [])
-            (insert_type ctxt #3
-                         (s', [tvar_a], @{typ "'a itself"}, false, 0, false))
-      end
-  in
-    Symtab.empty
-    |> is_type_enc_fairly_sound type_enc
-       ? (fold (fold add_fact_syms) [conjs, facts]
-          #> (case type_enc of
-                Simple_Types (First_Order, Polymorphic, _) =>
-                if avoid_first_order_ghost_type_vars then add_TYPE_const ()
-                else I
-              | Simple_Types _ => I
-              | _ => fold add_undefined_const (var_types ())))
-  end
-
-(* We add "bool" in case the helper "True_or_False" is included later. *)
-fun default_mono level =
-  {maybe_finite_Ts = [@{typ bool}],
-   surely_finite_Ts = [@{typ bool}],
-   maybe_infinite_Ts = known_infinite_types,
-   surely_infinite_Ts =
-     case level of
-       Noninf_Nonmono_Types (Strict, _) => []
-     | _ => known_infinite_types,
-   maybe_nonmono_Ts = [@{typ bool}]}
-
-(* This inference is described in section 2.3 of Claessen et al.'s "Sorting it
-   out with monotonicity" paper presented at CADE 2011. *)
-fun add_iterm_mononotonicity_info _ _ (SOME false) _ mono = mono
-  | add_iterm_mononotonicity_info ctxt level _
-        (IApp (IApp (IConst ((s, _), Type (_, [T, _]), _), tm1), tm2))
-        (mono as {maybe_finite_Ts, surely_finite_Ts, maybe_infinite_Ts,
-                  surely_infinite_Ts, maybe_nonmono_Ts}) =
-    if is_tptp_equal s andalso exists is_maybe_universal_var [tm1, tm2] then
-      case level of
-        Noninf_Nonmono_Types (strictness, _) =>
-        if exists (type_instance ctxt T) surely_infinite_Ts orelse
-           member (type_equiv ctxt) maybe_finite_Ts T then
-          mono
-        else if is_type_kind_of_surely_infinite ctxt strictness
-                                                surely_infinite_Ts T then
-          {maybe_finite_Ts = maybe_finite_Ts,
-           surely_finite_Ts = surely_finite_Ts,
-           maybe_infinite_Ts = maybe_infinite_Ts,
-           surely_infinite_Ts = surely_infinite_Ts |> insert_type ctxt I T,
-           maybe_nonmono_Ts = maybe_nonmono_Ts}
-        else
-          {maybe_finite_Ts = maybe_finite_Ts |> insert (type_equiv ctxt) T,
-           surely_finite_Ts = surely_finite_Ts,
-           maybe_infinite_Ts = maybe_infinite_Ts,
-           surely_infinite_Ts = surely_infinite_Ts,
-           maybe_nonmono_Ts = maybe_nonmono_Ts |> insert_type ctxt I T}
-      | Fin_Nonmono_Types _ =>
-        if exists (type_instance ctxt T) surely_finite_Ts orelse
-           member (type_equiv ctxt) maybe_infinite_Ts T then
-          mono
-        else if is_type_surely_finite ctxt T then
-          {maybe_finite_Ts = maybe_finite_Ts,
-           surely_finite_Ts = surely_finite_Ts |> insert_type ctxt I T,
-           maybe_infinite_Ts = maybe_infinite_Ts,
-           surely_infinite_Ts = surely_infinite_Ts,
-           maybe_nonmono_Ts = maybe_nonmono_Ts |> insert_type ctxt I T}
-        else
-          {maybe_finite_Ts = maybe_finite_Ts,
-           surely_finite_Ts = surely_finite_Ts,
-           maybe_infinite_Ts = maybe_infinite_Ts |> insert (type_equiv ctxt) T,
-           surely_infinite_Ts = surely_infinite_Ts,
-           maybe_nonmono_Ts = maybe_nonmono_Ts}
-      | _ => mono
-    else
-      mono
-  | add_iterm_mononotonicity_info _ _ _ _ mono = mono
-fun add_fact_mononotonicity_info ctxt level
-        ({kind, iformula, ...} : translated_formula) =
-  formula_fold (SOME (kind <> Conjecture))
-               (add_iterm_mononotonicity_info ctxt level) iformula
-fun mononotonicity_info_for_facts ctxt type_enc facts =
-  let val level = level_of_type_enc type_enc in
-    default_mono level
-    |> is_type_level_monotonicity_based level
-       ? fold (add_fact_mononotonicity_info ctxt level) facts
-  end
-
-fun add_iformula_monotonic_types ctxt mono type_enc =
-  let
-    val level = level_of_type_enc type_enc
-    val should_encode = should_encode_type ctxt mono level
-    fun add_type T = not (should_encode T) ? insert_type ctxt I T
-    fun add_args (IApp (tm1, tm2)) = add_args tm1 #> add_term tm2
-      | add_args _ = I
-    and add_term tm = add_type (ityp_of tm) #> add_args tm
-  in formula_fold NONE (K add_term) end
-fun add_fact_monotonic_types ctxt mono type_enc =
-  add_iformula_monotonic_types ctxt mono type_enc |> fact_lift
-fun monotonic_types_for_facts ctxt mono type_enc facts =
-  let val level = level_of_type_enc type_enc in
-    [] |> (polymorphism_of_type_enc type_enc = Polymorphic andalso
-           is_type_level_monotonicity_based level andalso
-           granularity_of_type_level level <> Ghost_Type_Arg_Vars)
-          ? fold (add_fact_monotonic_types ctxt mono type_enc) facts
-  end
-
-fun formula_line_for_guards_mono_type ctxt format mono type_enc T =
-  Formula (guards_sym_formula_prefix ^
-           ascii_of (mangled_type format type_enc T),
-           Axiom,
-           IConst (`make_bound_var "X", T, [])
-           |> type_guard_iterm format type_enc T
-           |> AAtom
-           |> formula_from_iformula ctxt [] format mono type_enc
-                                    always_guard_var_in_formula (SOME true)
-           |> close_formula_universally
-           |> bound_tvars type_enc true (atomic_types_of T),
-           isabelle_info format introN, NONE)
-
-fun formula_line_for_tags_mono_type ctxt format mono type_enc T =
-  let val x_var = ATerm (`make_bound_var "X", []) in
-    Formula (tags_sym_formula_prefix ^
-             ascii_of (mangled_type format type_enc T),
-             Axiom,
-             eq_formula type_enc (atomic_types_of T) false
-                  (tag_with_type ctxt format mono type_enc NONE T x_var) x_var,
-             isabelle_info format simpN, NONE)
-  end
-
-fun problem_lines_for_mono_types ctxt format mono type_enc Ts =
-  case type_enc of
-    Simple_Types _ => []
-  | Guards _ =>
-    map (formula_line_for_guards_mono_type ctxt format mono type_enc) Ts
-  | Tags _ => map (formula_line_for_tags_mono_type ctxt format mono type_enc) Ts
-
-fun decl_line_for_sym ctxt format mono type_enc s
-                      (s', T_args, T, pred_sym, ary, _) =
-  let
-    val thy = Proof_Context.theory_of ctxt
-    val (T, T_args) =
-      if null T_args then
-        (T, [])
-      else case unprefix_and_unascii const_prefix s of
-        SOME s' =>
-        let
-          val s' = s' |> invert_const
-          val T = s' |> robust_const_type thy
-        in (T, robust_const_typargs thy (s', T)) end
-      | NONE => raise Fail "unexpected type arguments"
-  in
-    Decl (sym_decl_prefix ^ s, (s, s'),
-          T |> fused_type ctxt mono (level_of_type_enc type_enc) ary
-            |> ho_type_from_typ format type_enc pred_sym ary
-            |> not (null T_args)
-               ? curry ATyAbs (map (tvar_name o fst o dest_TVar) T_args))
-  end
-
-fun formula_line_for_guards_sym_decl ctxt format conj_sym_kind mono type_enc n s
-                                     j (s', T_args, T, _, ary, in_conj) =
-  let
-    val thy = Proof_Context.theory_of ctxt
-    val (kind, maybe_negate) =
-      if in_conj then (conj_sym_kind, conj_sym_kind = Conjecture ? mk_anot)
-      else (Axiom, I)
-    val (arg_Ts, res_T) = chop_fun ary T
-    val bound_names = 1 upto ary |> map (`I o make_bound_var o string_of_int)
-    val bounds =
-      bound_names ~~ arg_Ts |> map (fn (name, T) => IConst (name, T, []))
-    val bound_Ts =
-      if exists (curry (op =) dummyT) T_args then
-        case level_of_type_enc type_enc of
-          All_Types => map SOME arg_Ts
-        | level =>
-          if granularity_of_type_level level = Ghost_Type_Arg_Vars then
-            let val ghosts = ghost_type_args thy s ary in
-              map2 (fn j => if member (op =) ghosts j then SOME else K NONE)
-                   (0 upto ary - 1) arg_Ts
-            end
-          else
-            replicate ary NONE
-      else
-        replicate ary NONE
-  in
-    Formula (guards_sym_formula_prefix ^ s ^
-             (if n > 1 then "_" ^ string_of_int j else ""), kind,
-             IConst ((s, s'), T, T_args)
-             |> fold (curry (IApp o swap)) bounds
-             |> type_guard_iterm format type_enc res_T
-             |> AAtom |> mk_aquant AForall (bound_names ~~ bound_Ts)
-             |> formula_from_iformula ctxt [] format mono type_enc
-                                      always_guard_var_in_formula (SOME true)
-             |> close_formula_universally
-             |> bound_tvars type_enc (n > 1) (atomic_types_of T)
-             |> maybe_negate,
-             isabelle_info format introN, NONE)
-  end
-
-fun formula_lines_for_tags_sym_decl ctxt format conj_sym_kind mono type_enc n s
-        (j, (s', T_args, T, pred_sym, ary, in_conj)) =
-  let
-    val thy = Proof_Context.theory_of ctxt
-    val level = level_of_type_enc type_enc
-    val grain = granularity_of_type_level level
-    val ident_base =
-      tags_sym_formula_prefix ^ s ^
-      (if n > 1 then "_" ^ string_of_int j else "")
-    val (kind, maybe_negate) =
-      if in_conj then (conj_sym_kind, conj_sym_kind = Conjecture ? mk_anot)
-      else (Axiom, I)
-    val (arg_Ts, res_T) = chop_fun ary T
-    val bound_names = 1 upto ary |> map (`I o make_bound_var o string_of_int)
-    val bounds = bound_names |> map (fn name => ATerm (name, []))
-    val cst = mk_aterm format type_enc (s, s') T_args
-    val eq = maybe_negate oo eq_formula type_enc (atomic_types_of T) pred_sym
-    val should_encode = should_encode_type ctxt mono level
-    val tag_with = tag_with_type ctxt format mono type_enc NONE
-    val add_formula_for_res =
-      if should_encode res_T then
-        let
-          val tagged_bounds =
-            if grain = Ghost_Type_Arg_Vars then
-              let val ghosts = ghost_type_args thy s ary in
-                map2 (fn (j, arg_T) => member (op =) ghosts j ? tag_with arg_T)
-                     (0 upto ary - 1 ~~ arg_Ts) bounds
-              end
-            else
-              bounds
-        in
-          cons (Formula (ident_base ^ "_res", kind,
-                         eq (tag_with res_T (cst bounds)) (cst tagged_bounds),
-                         isabelle_info format simpN, NONE))
-        end
-      else
-        I
-    fun add_formula_for_arg k =
-      let val arg_T = nth arg_Ts k in
-        if should_encode arg_T then
-          case chop k bounds of
-            (bounds1, bound :: bounds2) =>
-            cons (Formula (ident_base ^ "_arg" ^ string_of_int (k + 1), kind,
-                           eq (cst (bounds1 @ tag_with arg_T bound :: bounds2))
-                              (cst bounds),
-                           isabelle_info format simpN, NONE))
-          | _ => raise Fail "expected nonempty tail"
-        else
-          I
-      end
-  in
-    [] |> not pred_sym ? add_formula_for_res
-       |> (Config.get ctxt type_tag_arguments andalso
-           grain = Positively_Naked_Vars)
-          ? fold add_formula_for_arg (ary - 1 downto 0)
-  end
-
-fun result_type_of_decl (_, _, T, _, ary, _) = chop_fun ary T |> snd
-
-fun rationalize_decls ctxt (decls as decl :: (decls' as _ :: _)) =
-    let
-      val T = result_type_of_decl decl
-              |> map_type_tvar (fn (z, _) => TVar (z, HOLogic.typeS))
-    in
-      if forall (type_generalization ctxt T o result_type_of_decl) decls' then
-        [decl]
-      else
-        decls
-    end
-  | rationalize_decls _ decls = decls
-
-fun problem_lines_for_sym_decls ctxt format conj_sym_kind mono type_enc
-                                (s, decls) =
-  case type_enc of
-    Simple_Types _ => [decl_line_for_sym ctxt format mono type_enc s (hd decls)]
-  | Guards (_, level) =>
-    let
-      val decls = decls |> rationalize_decls ctxt
-      val n = length decls
-      val decls =
-        decls |> filter (should_encode_type ctxt mono level
-                         o result_type_of_decl)
-    in
-      (0 upto length decls - 1, decls)
-      |-> map2 (formula_line_for_guards_sym_decl ctxt format conj_sym_kind mono
-                                                 type_enc n s)
-    end
-  | Tags (_, level) =>
-    if granularity_of_type_level level = All_Vars then
-      []
-    else
-      let val n = length decls in
-        (0 upto n - 1 ~~ decls)
-        |> maps (formula_lines_for_tags_sym_decl ctxt format conj_sym_kind mono
-                                                 type_enc n s)
-      end
-
-fun problem_lines_for_sym_decl_table ctxt format conj_sym_kind mono type_enc
-                                     mono_Ts sym_decl_tab =
-  let
-    val syms = sym_decl_tab |> Symtab.dest |> sort_wrt fst
-    val mono_lines =
-      problem_lines_for_mono_types ctxt format mono type_enc mono_Ts
-    val decl_lines =
-      fold_rev (append o problem_lines_for_sym_decls ctxt format conj_sym_kind
-                             mono type_enc)
-               syms []
-  in mono_lines @ decl_lines end
-
-fun needs_type_tag_idempotence ctxt (Tags (poly, level)) =
-    Config.get ctxt type_tag_idempotence andalso
-    is_type_level_monotonicity_based level andalso
-    poly <> Mangled_Monomorphic
-  | needs_type_tag_idempotence _ _ = false
-
-val implicit_declsN = "Should-be-implicit typings"
-val explicit_declsN = "Explicit typings"
-val factsN = "Relevant facts"
-val class_relsN = "Class relationships"
-val aritiesN = "Arities"
-val helpersN = "Helper facts"
-val conjsN = "Conjectures"
-val free_typesN = "Type variables"
-
-(* TFF allows implicit declarations of types, function symbols, and predicate
-   symbols (with "$i" as the type of individuals), but some provers (e.g.,
-   SNARK) require explicit declarations. The situation is similar for THF. *)
-
-fun default_type type_enc pred_sym s =
-  let
-    val ind =
-      case type_enc of
-        Simple_Types _ =>
-        if String.isPrefix type_const_prefix s then atype_of_types
-        else individual_atype
-      | _ => individual_atype
-    fun typ 0 = if pred_sym then bool_atype else ind
-      | typ ary = AFun (ind, typ (ary - 1))
-  in typ end
-
-fun nary_type_constr_type n =
-  funpow n (curry AFun atype_of_types) atype_of_types
-
-fun undeclared_syms_in_problem type_enc problem =
-  let
-    val declared = declared_syms_in_problem problem
-    fun do_sym name ty =
-      if member (op =) declared name then I else AList.default (op =) (name, ty)
-    fun do_type (AType (name as (s, _), tys)) =
-        is_tptp_user_symbol s
-        ? do_sym name (fn () => nary_type_constr_type (length tys))
-        #> fold do_type tys
-      | do_type (AFun (ty1, ty2)) = do_type ty1 #> do_type ty2
-      | do_type (ATyAbs (_, ty)) = do_type ty
-    fun do_term pred_sym (ATerm (name as (s, _), tms)) =
-        is_tptp_user_symbol s
-        ? do_sym name (fn _ => default_type type_enc pred_sym s (length tms))
-        #> fold (do_term false) tms
-      | do_term _ (AAbs ((_, ty), tm)) = do_type ty #> do_term false tm
-    fun do_formula (AQuant (_, xs, phi)) =
-        fold do_type (map_filter snd xs) #> do_formula phi
-      | do_formula (AConn (_, phis)) = fold do_formula phis
-      | do_formula (AAtom tm) = do_term true tm
-    fun do_problem_line (Decl (_, _, ty)) = do_type ty
-      | do_problem_line (Formula (_, _, phi, _, _)) = do_formula phi
-  in
-    fold (fold do_problem_line o snd) problem []
-    |> filter_out (is_built_in_tptp_symbol o fst o fst)
-  end
-
-fun declare_undeclared_syms_in_atp_problem type_enc problem =
-  let
-    val decls =
-      problem
-      |> undeclared_syms_in_problem type_enc
-      |> sort_wrt (fst o fst)
-      |> map (fn (x as (s, _), ty) => Decl (type_decl_prefix ^ s, x, ty ()))
-  in (implicit_declsN, decls) :: problem end
-
-fun exists_subdtype P =
-  let
-    fun ex U = P U orelse
-      (case U of Datatype.DtType (_, Us) => exists ex Us | _ => false)
-  in ex end
-
-fun is_poly_constr (_, Us) =
-  exists (exists_subdtype (fn Datatype.DtTFree _ => true | _ => false)) Us
-
-fun all_constrs_of_polymorphic_datatypes thy =
-  Symtab.fold (snd
-               #> #descr
-               #> maps (snd #> #3)
-               #> (fn cs => exists is_poly_constr cs ? append cs))
-              (Datatype.get_all thy) []
-  |> List.partition is_poly_constr
-  |> pairself (map fst)
-
-(* Forcing explicit applications is expensive for polymorphic encodings, because
-   it takes only one existential variable ranging over "'a => 'b" to ruin
-   everything. Hence we do it only if there are few facts (is normally the case
-   for "metis" and the minimizer. *)
-val explicit_apply_threshold = 50
-
-fun prepare_atp_problem ctxt format conj_sym_kind prem_kind type_enc exporter
-                        lam_trans readable_names preproc hyp_ts concl_t facts =
-  let
-    val thy = Proof_Context.theory_of ctxt
-    val type_enc = type_enc |> adjust_type_enc format
-    val explicit_apply =
-      if polymorphism_of_type_enc type_enc <> Polymorphic orelse
-         length facts <= explicit_apply_threshold then
-        NONE
-      else
-        SOME false
-    val lam_trans =
-      if lam_trans = keep_lamsN andalso
-         not (is_type_enc_higher_order type_enc) then
-        error ("Lambda translation scheme incompatible with first-order \
-               \encoding.")
-      else
-        lam_trans
-    val (fact_names, classes, conjs, facts, class_rel_clauses, arity_clauses,
-         lifted) =
-      translate_formulas ctxt format prem_kind type_enc lam_trans preproc hyp_ts
-                         concl_t facts
-    val sym_tab = sym_table_for_facts ctxt type_enc explicit_apply conjs facts
-    val mono = conjs @ facts |> mononotonicity_info_for_facts ctxt type_enc
-    val (polym_constrs, monom_constrs) =
-      all_constrs_of_polymorphic_datatypes thy
-      |>> map (make_fixed_const (SOME format))
-    val firstorderize =
-      firstorderize_fact thy monom_constrs format type_enc sym_tab
-    val (conjs, facts) = (conjs, facts) |> pairself (map firstorderize)
-    val sym_tab = sym_table_for_facts ctxt type_enc (SOME false) conjs facts
-    val helpers =
-      sym_tab |> helper_facts_for_sym_table ctxt format type_enc
-              |> map firstorderize
-    val mono_Ts =
-      helpers @ conjs @ facts |> monotonic_types_for_facts ctxt mono type_enc
-    val class_decl_lines = decl_lines_for_classes type_enc classes
-    val sym_decl_lines =
-      (conjs, helpers @ facts)
-      |> sym_decl_table_for_facts ctxt format type_enc sym_tab
-      |> problem_lines_for_sym_decl_table ctxt format conj_sym_kind mono
-                                               type_enc mono_Ts
-    val helper_lines =
-      0 upto length helpers - 1 ~~ helpers
-      |> map (formula_line_for_fact ctxt polym_constrs format helper_prefix I
-                                    false true mono type_enc)
-      |> (if needs_type_tag_idempotence ctxt type_enc then
-            cons (type_tag_idempotence_fact format type_enc)
-          else
-            I)
-    (* Reordering these might confuse the proof reconstruction code or the SPASS
-       FLOTTER hack. *)
-    val problem =
-      [(explicit_declsN, class_decl_lines @ sym_decl_lines),
-       (factsN,
-        map (formula_line_for_fact ctxt polym_constrs format fact_prefix
-                 ascii_of (not exporter) (not exporter) mono type_enc)
-            (0 upto length facts - 1 ~~ facts)),
-       (class_relsN,
-        map (formula_line_for_class_rel_clause format type_enc)
-            class_rel_clauses),
-       (aritiesN,
-        map (formula_line_for_arity_clause format type_enc) arity_clauses),
-       (helpersN, helper_lines),
-       (conjsN,
-        map (formula_line_for_conjecture ctxt polym_constrs format mono
-                                         type_enc) conjs),
-       (free_typesN, formula_lines_for_free_types type_enc (facts @ conjs))]
-    val problem =
-      problem
-      |> (case format of
-            CNF => ensure_cnf_problem
-          | CNF_UEQ => filter_cnf_ueq_problem
-          | FOF => I
-          | TFF (_, TPTP_Implicit) => I
-          | THF (_, TPTP_Implicit, _) => I
-          | _ => declare_undeclared_syms_in_atp_problem type_enc)
-    val (problem, pool) = problem |> nice_atp_problem readable_names format
-    fun add_sym_ary (s, {min_ary, ...} : sym_info) =
-      min_ary > 0 ? Symtab.insert (op =) (s, min_ary)
-  in
-    (problem,
-     case pool of SOME the_pool => snd the_pool | NONE => Symtab.empty,
-     fact_names |> Vector.fromList,
-     lifted,
-     Symtab.empty |> Symtab.fold add_sym_ary sym_tab)
-  end
-
-(* FUDGE *)
-val conj_weight = 0.0
-val hyp_weight = 0.1
-val fact_min_weight = 0.2
-val fact_max_weight = 1.0
-val type_info_default_weight = 0.8
-
-fun add_term_weights weight (ATerm (s, tms)) =
-    is_tptp_user_symbol s ? Symtab.default (s, weight)
-    #> fold (add_term_weights weight) tms
-  | add_term_weights weight (AAbs (_, tm)) = add_term_weights weight tm
-fun add_problem_line_weights weight (Formula (_, _, phi, _, _)) =
-    formula_fold NONE (K (add_term_weights weight)) phi
-  | add_problem_line_weights _ _ = I
-
-fun add_conjectures_weights [] = I
-  | add_conjectures_weights conjs =
-    let val (hyps, conj) = split_last conjs in
-      add_problem_line_weights conj_weight conj
-      #> fold (add_problem_line_weights hyp_weight) hyps
-    end
-
-fun add_facts_weights facts =
-  let
-    val num_facts = length facts
-    fun weight_of j =
-      fact_min_weight + (fact_max_weight - fact_min_weight) * Real.fromInt j
-                        / Real.fromInt num_facts
-  in
-    map weight_of (0 upto num_facts - 1) ~~ facts
-    |> fold (uncurry add_problem_line_weights)
-  end
-
-(* Weights are from 0.0 (most important) to 1.0 (least important). *)
-fun atp_problem_weights problem =
-  let val get = these o AList.lookup (op =) problem in
-    Symtab.empty
-    |> add_conjectures_weights (get free_typesN @ get conjsN)
-    |> add_facts_weights (get factsN)
-    |> fold (fold (add_problem_line_weights type_info_default_weight) o get)
-            [explicit_declsN, class_relsN, aritiesN]
-    |> Symtab.dest
-    |> sort (prod_ord Real.compare string_ord o pairself swap)
-  end
-
-end;