src/HOL/Nominal/nominal_inductive.ML
author wenzelm
Sat Oct 06 16:50:04 2007 +0200 (2007-10-06)
changeset 24867 e5b55d7be9bb
parent 24861 cc669ca5f382
child 25824 f56dd9745d1b
permissions -rw-r--r--
simplified interfaces for outer syntax;
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(*  Title:      HOL/Nominal/nominal_inductive.ML
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    ID:         $Id$
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    Author:     Stefan Berghofer, TU Muenchen
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Infrastructure for proving equivariance and strong induction theorems
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for inductive predicates involving nominal datatypes.
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*)
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signature NOMINAL_INDUCTIVE =
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sig
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  val prove_strong_ind: string -> (string * string list) list -> theory -> Proof.state
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  val prove_eqvt: string -> string list -> theory -> theory
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end
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structure NominalInductive : NOMINAL_INDUCTIVE =
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struct
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val inductive_forall_name = "HOL.induct_forall";
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val inductive_forall_def = thm "induct_forall_def";
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val inductive_atomize = thms "induct_atomize";
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val inductive_rulify = thms "induct_rulify";
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fun rulify_term thy = MetaSimplifier.rewrite_term thy inductive_rulify [];
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val atomize_conv =
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  MetaSimplifier.rewrite_cterm (true, false, false) (K (K NONE))
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    (HOL_basic_ss addsimps inductive_atomize);
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val atomize_intr = Conv.fconv_rule (Conv.prems_conv ~1 atomize_conv);
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fun atomize_induct ctxt = Conv.fconv_rule (Conv.prems_conv ~1
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  (Conv.forall_conv ~1 (K (Conv.prems_conv ~1 atomize_conv)) ctxt));
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val finite_Un = thm "finite_Un";
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val supp_prod = thm "supp_prod";
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val fresh_prod = thm "fresh_prod";
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val perm_bool = mk_meta_eq (thm "perm_bool");
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val perm_boolI = thm "perm_boolI";
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val (_, [perm_boolI_pi, _]) = Drule.strip_comb (snd (Thm.dest_comb
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  (Drule.strip_imp_concl (cprop_of perm_boolI))));
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fun mk_perm_bool_simproc names = Simplifier.simproc_i
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  (theory_of_thm perm_bool) "perm_bool" [@{term "perm pi x"}] (fn thy => fn ss =>
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    fn Const ("Nominal.perm", _) $ _ $ t =>
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         if the_default "" (try (head_of #> dest_Const #> fst) t) mem names
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         then SOME perm_bool else NONE
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     | _ => NONE);
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val allE_Nil = read_instantiate_sg (the_context()) [("x", "[]")] allE;
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fun transp ([] :: _) = []
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  | transp xs = map hd xs :: transp (map tl xs);
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fun add_binders thy i (t as (_ $ _)) bs = (case strip_comb t of
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      (Const (s, T), ts) => (case strip_type T of
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        (Ts, Type (tname, _)) =>
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          (case NominalPackage.get_nominal_datatype thy tname of
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             NONE => fold (add_binders thy i) ts bs
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           | SOME {descr, index, ...} => (case AList.lookup op =
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                 (#3 (the (AList.lookup op = descr index))) s of
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               NONE => fold (add_binders thy i) ts bs
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             | SOME cargs => fst (fold (fn (xs, x) => fn (bs', cargs') =>
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                 let val (cargs1, (u, _) :: cargs2) = chop (length xs) cargs'
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                 in (add_binders thy i u
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                   (fold (fn (u, T) =>
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                      if exists (fn j => j < i) (loose_bnos u) then I
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                      else insert (op aconv o pairself fst)
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                        (incr_boundvars (~i) u, T)) cargs1 bs'), cargs2)
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                 end) cargs (bs, ts ~~ Ts))))
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      | _ => fold (add_binders thy i) ts bs)
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    | (u, ts) => add_binders thy i u (fold (add_binders thy i) ts bs))
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  | add_binders thy i (Abs (_, _, t)) bs = add_binders thy (i + 1) t bs
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  | add_binders thy i _ bs = bs;
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fun split_conj f names (Const ("op &", _) $ p $ q) _ = (case head_of p of
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      Const (name, _) =>
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        if name mem names then SOME (f p q) else NONE
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    | _ => NONE)
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  | split_conj _ _ _ _ = NONE;
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fun strip_all [] t = t
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  | strip_all (_ :: xs) (Const ("All", _) $ Abs (s, T, t)) = strip_all xs t;
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(*********************************************************************)
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(* maps  R ... & (ALL pi_1 ... pi_n z. P z (pi_1 o ... o pi_n o t))  *)
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(* or    ALL pi_1 ... pi_n. P (pi_1 o ... o pi_n o t)                *)
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(* to    R ... & id (ALL z. (pi_1 o ... o pi_n o t))                 *)
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(* or    id (ALL z. (pi_1 o ... o pi_n o t))                         *)
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(*                                                                   *)
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(* where "id" protects the subformula from simplification            *)
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(*********************************************************************)
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fun inst_conj_all names ps pis (Const ("op &", _) $ p $ q) _ =
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      (case head_of p of
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         Const (name, _) =>
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           if name mem names then SOME (HOLogic.mk_conj (p,
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             Const ("Fun.id", HOLogic.boolT --> HOLogic.boolT) $
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               (subst_bounds (pis, strip_all pis q))))
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           else NONE
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       | _ => NONE)
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  | inst_conj_all names ps pis t u =
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      if member (op aconv) ps (head_of u) then
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        SOME (Const ("Fun.id", HOLogic.boolT --> HOLogic.boolT) $
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          (subst_bounds (pis, strip_all pis t)))
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      else NONE
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  | inst_conj_all _ _ _ _ _ = NONE;
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fun inst_conj_all_tac k = EVERY
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  [TRY (EVERY [etac conjE 1, rtac conjI 1, atac 1]),
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   REPEAT_DETERM_N k (etac allE 1),
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   simp_tac (HOL_basic_ss addsimps [id_apply]) 1];
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fun map_term f t u = (case f t u of
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      NONE => map_term' f t u | x => x)
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and map_term' f (t $ u) (t' $ u') = (case (map_term f t t', map_term f u u') of
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      (NONE, NONE) => NONE
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    | (SOME t'', NONE) => SOME (t'' $ u)
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    | (NONE, SOME u'') => SOME (t $ u'')
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    | (SOME t'', SOME u'') => SOME (t'' $ u''))
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  | map_term' f (Abs (s, T, t)) (Abs (s', T', t')) = (case map_term f t t' of
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      NONE => NONE
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    | SOME t'' => SOME (Abs (s, T, t'')))
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  | map_term' _ _ _ = NONE;
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(*********************************************************************)
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(*         Prove  F[f t]  from  F[t],  where F is monotone           *)
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(*********************************************************************)
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fun map_thm ctxt f tac monos opt th =
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  let
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    val prop = prop_of th;
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    fun prove t =
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      Goal.prove ctxt [] [] t (fn _ =>
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        EVERY [cut_facts_tac [th] 1, etac rev_mp 1,
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          REPEAT_DETERM (FIRSTGOAL (resolve_tac monos)),
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          REPEAT_DETERM (rtac impI 1 THEN (atac 1 ORELSE tac))])
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  in Option.map prove (map_term f prop (the_default prop opt)) end;
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fun prove_strong_ind s avoids thy =
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  let
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    val ctxt = ProofContext.init thy;
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    val ({names, ...}, {raw_induct, ...}) =
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      InductivePackage.the_inductive ctxt (Sign.intern_const thy s);
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    val raw_induct = atomize_induct ctxt raw_induct;
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    val monos = InductivePackage.get_monos ctxt;
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    val eqvt_thms = NominalThmDecls.get_eqvt_thms ctxt;
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    val _ = (case names \\ foldl (apfst prop_of #> add_term_consts) [] eqvt_thms of
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        [] => ()
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      | xs => error ("Missing equivariance theorem for predicate(s): " ^
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          commas_quote xs));
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    val induct_cases = map fst (fst (RuleCases.get (the
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      (Induct.lookup_inductP ctxt (hd names)))));
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    val raw_induct' = Logic.unvarify (prop_of raw_induct);
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    val concls = raw_induct' |> Logic.strip_imp_concl |> HOLogic.dest_Trueprop |>
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      HOLogic.dest_conj |> map (HOLogic.dest_imp ##> strip_comb);
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    val ps = map (fst o snd) concls;
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    val _ = (case duplicates (op = o pairself fst) avoids of
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        [] => ()
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      | xs => error ("Duplicate case names: " ^ commas_quote (map fst xs)));
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    val _ = assert_all (null o duplicates op = o snd) avoids
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      (fn (a, _) => error ("Duplicate variable names for case " ^ quote a));
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    val _ = (case map fst avoids \\ induct_cases of
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        [] => ()
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      | xs => error ("No such case(s) in inductive definition: " ^ commas_quote xs));
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    val avoids' = map (fn name =>
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      (name, the_default [] (AList.lookup op = avoids name))) induct_cases;
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    fun mk_avoids params (name, ps) =
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      let val k = length params - 1
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      in map (fn x => case find_index (equal x o fst) params of
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          ~1 => error ("No such variable in case " ^ quote name ^
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            " of inductive definition: " ^ quote x)
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        | i => (Bound (k - i), snd (nth params i))) ps
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      end;
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    val prems = map (fn (prem, avoid) =>
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      let
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        val prems = map (incr_boundvars 1) (Logic.strip_assums_hyp prem);
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        val concl = incr_boundvars 1 (Logic.strip_assums_concl prem);
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        val params = Logic.strip_params prem
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      in
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        (params,
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         fold (add_binders thy 0) (prems @ [concl]) [] @
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           map (apfst (incr_boundvars 1)) (mk_avoids params avoid),
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         prems, strip_comb (HOLogic.dest_Trueprop concl))
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      end) (Logic.strip_imp_prems raw_induct' ~~ avoids');
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    val atomTs = distinct op = (maps (map snd o #2) prems);
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    val ind_sort = if null atomTs then HOLogic.typeS
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      else Sign.certify_sort thy (map (fn T => Sign.intern_class thy
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        ("fs_" ^ Sign.base_name (fst (dest_Type T)))) atomTs);
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    val fs_ctxt_tyname = Name.variant (map fst (term_tfrees raw_induct')) "'n";
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    val fs_ctxt_name = Name.variant (add_term_names (raw_induct', [])) "z";
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    val fsT = TFree (fs_ctxt_tyname, ind_sort);
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    val inductive_forall_def' = Drule.instantiate'
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      [SOME (ctyp_of thy fsT)] [] inductive_forall_def;
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    fun lift_pred' t (Free (s, T)) ts =
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      list_comb (Free (s, fsT --> T), t :: ts);
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    val lift_pred = lift_pred' (Bound 0);
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    fun lift_prem (t as (f $ u)) =
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          let val (p, ts) = strip_comb t
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          in
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            if p mem ps then
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              Const (inductive_forall_name,
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                (fsT --> HOLogic.boolT) --> HOLogic.boolT) $
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                  Abs ("z", fsT, lift_pred p (map (incr_boundvars 1) ts))
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            else lift_prem f $ lift_prem u
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          end
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      | lift_prem (Abs (s, T, t)) = Abs (s, T, lift_prem t)
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      | lift_prem t = t;
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    fun mk_distinct [] = []
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      | mk_distinct ((x, T) :: xs) = List.mapPartial (fn (y, U) =>
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          if T = U then SOME (HOLogic.mk_Trueprop
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            (HOLogic.mk_not (HOLogic.eq_const T $ x $ y)))
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          else NONE) xs @ mk_distinct xs;
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    fun mk_fresh (x, T) = HOLogic.mk_Trueprop
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      (Const ("Nominal.fresh", T --> fsT --> HOLogic.boolT) $ x $ Bound 0);
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    val (prems', prems'') = split_list (map (fn (params, bvars, prems, (p, ts)) =>
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      let
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        val params' = params @ [("y", fsT)];
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        val prem = Logic.list_implies
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          (map mk_fresh bvars @ mk_distinct bvars @
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           map (fn prem =>
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             if null (term_frees prem inter ps) then prem
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             else lift_prem prem) prems,
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           HOLogic.mk_Trueprop (lift_pred p ts));
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        val vs = map (Var o apfst (rpair 0)) (rename_wrt_term prem params')
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      in
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        (list_all (params', prem), (rev vs, subst_bounds (vs, prem)))
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      end) prems);
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    val ind_vars =
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      (DatatypeProp.indexify_names (replicate (length atomTs) "pi") ~~
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       map NominalAtoms.mk_permT atomTs) @ [("z", fsT)];
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    val ind_Ts = rev (map snd ind_vars);
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    val concl = HOLogic.mk_Trueprop (foldr1 HOLogic.mk_conj
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      (map (fn (prem, (p, ts)) => HOLogic.mk_imp (prem,
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        HOLogic.list_all (ind_vars, lift_pred p
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          (map (fold_rev (NominalPackage.mk_perm ind_Ts)
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            (map Bound (length atomTs downto 1))) ts)))) concls));
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    val concl' = HOLogic.mk_Trueprop (foldr1 HOLogic.mk_conj
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      (map (fn (prem, (p, ts)) => HOLogic.mk_imp (prem,
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        lift_pred' (Free (fs_ctxt_name, fsT)) p ts)) concls));
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    val vc_compat = map (fn (params, bvars, prems, (p, ts)) =>
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      map (fn q => list_all (params, incr_boundvars ~1 (Logic.list_implies
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          (List.mapPartial (fn prem =>
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             if null (ps inter term_frees prem) then SOME prem
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             else map_term (split_conj (K o I) names) prem prem) prems, q))))
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        (mk_distinct bvars @
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         maps (fn (t, T) => map (fn (u, U) => HOLogic.mk_Trueprop
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           (Const ("Nominal.fresh", U --> T --> HOLogic.boolT) $ u $ t)) bvars)
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             (ts ~~ binder_types (fastype_of p)))) prems;
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    val perm_pi_simp = PureThy.get_thms thy (Name "perm_pi_simp");
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    val pt2_atoms = map (fn aT => PureThy.get_thm thy
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      (Name ("pt_" ^ Sign.base_name (fst (dest_Type aT)) ^ "2"))) atomTs;
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    val eqvt_ss = HOL_basic_ss addsimps (eqvt_thms @ perm_pi_simp @ pt2_atoms)
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      addsimprocs [mk_perm_bool_simproc ["Fun.id"]];
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    val fresh_bij = PureThy.get_thms thy (Name "fresh_bij");
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    val perm_bij = PureThy.get_thms thy (Name "perm_bij");
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    val fs_atoms = map (fn aT => PureThy.get_thm thy
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      (Name ("fs_" ^ Sign.base_name (fst (dest_Type aT)) ^ "1"))) atomTs;
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    val exists_fresh' = PureThy.get_thms thy (Name "exists_fresh'");
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    val fresh_atm = PureThy.get_thms thy (Name "fresh_atm");
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    val calc_atm = PureThy.get_thms thy (Name "calc_atm");
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    val perm_fresh_fresh = PureThy.get_thms thy (Name "perm_fresh_fresh");
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    fun obtain_fresh_name ts T (freshs1, freshs2, ctxt) =
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      let
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        (** protect terms to avoid that supp_prod interferes with   **)
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        (** pairs used in introduction rules of inductive predicate **)
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        fun protect t =
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          let val T = fastype_of t in Const ("Fun.id", T --> T) $ t end;
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        val p = foldr1 HOLogic.mk_prod (map protect ts @ freshs1);
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   283
        val ex = Goal.prove ctxt [] [] (HOLogic.mk_Trueprop
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   284
            (HOLogic.exists_const T $ Abs ("x", T,
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   285
              Const ("Nominal.fresh", T --> fastype_of p --> HOLogic.boolT) $
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   286
                Bound 0 $ p)))
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   287
          (fn _ => EVERY
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   288
            [resolve_tac exists_fresh' 1,
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   289
             simp_tac (HOL_ss addsimps (supp_prod :: finite_Un :: fs_atoms)) 1]);
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   290
        val (([cx], ths), ctxt') = Obtain.result
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   291
          (fn _ => EVERY
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   292
            [etac exE 1,
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   293
             full_simp_tac (HOL_ss addsimps (fresh_prod :: fresh_atm)) 1,
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   294
             full_simp_tac (HOL_basic_ss addsimps [id_apply]) 1,
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   295
             REPEAT (etac conjE 1)])
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   296
          [ex] ctxt
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   297
      in (freshs1 @ [term_of cx], freshs2 @ ths, ctxt') end;
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   298
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   299
    fun mk_proof thy thss =
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   300
      let val ctxt = ProofContext.init thy
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   301
      in Goal.prove_global thy [] prems' concl' (fn ihyps =>
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   302
        let val th = Goal.prove ctxt [] [] concl (fn {context, ...} =>
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   303
          rtac raw_induct 1 THEN
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   304
          EVERY (maps (fn ((((_, bvars, oprems, _), vc_compat_ths), ihyp), (vs, ihypt)) =>
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   305
            [REPEAT (rtac allI 1), simp_tac eqvt_ss 1,
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   306
             SUBPROOF (fn {prems = gprems, params, concl, context = ctxt', ...} =>
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   307
               let
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   308
                 val (params', (pis, z)) =
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   309
                   chop (length params - length atomTs - 1) (map term_of params) ||>
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   310
                   split_last;
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   311
                 val bvars' = map
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   312
                   (fn (Bound i, T) => (nth params' (length params' - i), T)
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   313
                     | (t, T) => (t, T)) bvars;
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   314
                 val pi_bvars = map (fn (t, _) =>
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   315
                   fold_rev (NominalPackage.mk_perm []) pis t) bvars';
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   316
                 val (P, ts) = strip_comb (HOLogic.dest_Trueprop (term_of concl));
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   317
                 val (freshs1, freshs2, ctxt'') = fold
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   318
                   (obtain_fresh_name (ts @ pi_bvars))
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   319
                   (map snd bvars') ([], [], ctxt');
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   320
                 val freshs2' = NominalPackage.mk_not_sym freshs2;
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   321
                 val pis' = map NominalPackage.perm_of_pair (pi_bvars ~~ freshs1);
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   322
                 fun concat_perm pi1 pi2 =
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   323
                   let val T = fastype_of pi1
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   324
                   in if T = fastype_of pi2 then
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   325
                       Const ("List.append", T --> T --> T) $ pi1 $ pi2
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   326
                     else pi2
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   327
                   end;
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   328
                 val pis'' = fold (concat_perm #> map) pis' pis;
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   329
                 val env = Pattern.first_order_match thy (ihypt, prop_of ihyp)
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   330
                   (Vartab.empty, Vartab.empty);
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   331
                 val ihyp' = Thm.instantiate ([], map (pairself (cterm_of thy))
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   332
                   (map (Envir.subst_vars env) vs ~~
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   333
                    map (fold_rev (NominalPackage.mk_perm [])
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   334
                      (rev pis' @ pis)) params' @ [z])) ihyp;
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   335
                 fun mk_pi th =
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   336
                   Simplifier.simplify (HOL_basic_ss addsimps [id_apply]
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   337
                       addsimprocs [NominalPackage.perm_simproc])
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   338
                     (Simplifier.simplify eqvt_ss
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   339
                       (fold_rev (fn pi => fn th' => th' RS Drule.cterm_instantiate
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   340
                         [(perm_boolI_pi, cterm_of thy pi)] perm_boolI)
berghofe@24570
   341
                           (rev pis' @ pis) th));
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   342
                 val (gprems1, gprems2) = split_list
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   343
                   (map (fn (th, t) =>
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   344
                      if null (term_frees t inter ps) then (SOME th, mk_pi th)
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   345
                      else
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   346
                        (map_thm ctxt (split_conj (K o I) names)
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   347
                           (etac conjunct1 1) monos NONE th,
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   348
                         mk_pi (the (map_thm ctxt (inst_conj_all names ps (rev pis''))
berghofe@24570
   349
                           (inst_conj_all_tac (length pis'')) monos (SOME t) th))))
berghofe@24570
   350
                      (gprems ~~ oprems)) |>> List.mapPartial I;
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   351
                 val vc_compat_ths' = map (fn th =>
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   352
                   let
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   353
                     val th' = gprems1 MRS
wenzelm@22901
   354
                       Thm.instantiate (Thm.first_order_match
wenzelm@23531
   355
                         (Conjunction.mk_conjunction_balanced (cprems_of th),
wenzelm@23531
   356
                          Conjunction.mk_conjunction_balanced (map cprop_of gprems1))) th;
berghofe@22530
   357
                     val (bop, lhs, rhs) = (case concl_of th' of
berghofe@22530
   358
                         _ $ (fresh $ lhs $ rhs) =>
berghofe@22530
   359
                           (fn t => fn u => fresh $ t $ u, lhs, rhs)
berghofe@22530
   360
                       | _ $ (_ $ (_ $ lhs $ rhs)) =>
berghofe@22530
   361
                           (curry (HOLogic.mk_not o HOLogic.mk_eq), lhs, rhs));
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   362
                     val th'' = Goal.prove ctxt'' [] [] (HOLogic.mk_Trueprop
berghofe@22530
   363
                         (bop (fold_rev (NominalPackage.mk_perm []) pis lhs)
berghofe@22530
   364
                            (fold_rev (NominalPackage.mk_perm []) pis rhs)))
berghofe@22530
   365
                       (fn _ => simp_tac (HOL_basic_ss addsimps
berghofe@22530
   366
                          (fresh_bij @ perm_bij)) 1 THEN rtac th' 1)
berghofe@22530
   367
                   in Simplifier.simplify (eqvt_ss addsimps fresh_atm) th'' end)
berghofe@22530
   368
                     vc_compat_ths;
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   369
                 val vc_compat_ths'' = NominalPackage.mk_not_sym vc_compat_ths';
berghofe@22530
   370
                 (** Since calc_atm simplifies (pi :: 'a prm) o (x :: 'b) to x **)
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   371
                 (** we have to pre-simplify the rewrite rules                 **)
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   372
                 val calc_atm_ss = HOL_ss addsimps calc_atm @
berghofe@22530
   373
                    map (Simplifier.simplify (HOL_ss addsimps calc_atm))
berghofe@22530
   374
                      (vc_compat_ths'' @ freshs2');
berghofe@22530
   375
                 val th = Goal.prove ctxt'' [] []
berghofe@22530
   376
                   (HOLogic.mk_Trueprop (list_comb (P $ hd ts,
berghofe@22530
   377
                     map (fold (NominalPackage.mk_perm []) pis') (tl ts))))
berghofe@22530
   378
                   (fn _ => EVERY ([simp_tac eqvt_ss 1, rtac ihyp' 1,
berghofe@22530
   379
                     REPEAT_DETERM_N (nprems_of ihyp - length gprems)
berghofe@22530
   380
                       (simp_tac calc_atm_ss 1),
berghofe@22530
   381
                     REPEAT_DETERM_N (length gprems)
berghofe@24570
   382
                       (simp_tac (HOL_ss
berghofe@24570
   383
                          addsimps inductive_forall_def' :: gprems2
berghofe@22530
   384
                          addsimprocs [NominalPackage.perm_simproc]) 1)]));
berghofe@22530
   385
                 val final = Goal.prove ctxt'' [] [] (term_of concl)
berghofe@22530
   386
                   (fn _ => cut_facts_tac [th] 1 THEN full_simp_tac (HOL_ss
berghofe@22530
   387
                     addsimps vc_compat_ths'' @ freshs2' @
berghofe@22530
   388
                       perm_fresh_fresh @ fresh_atm) 1);
berghofe@22530
   389
                 val final' = ProofContext.export ctxt'' ctxt' [final];
berghofe@22530
   390
               in resolve_tac final' 1 end) context 1])
berghofe@22530
   391
                 (prems ~~ thss ~~ ihyps ~~ prems'')))
berghofe@22530
   392
        in
berghofe@22530
   393
          cut_facts_tac [th] 1 THEN REPEAT (etac conjE 1) THEN
berghofe@22530
   394
          REPEAT (REPEAT (resolve_tac [conjI, impI] 1) THEN
berghofe@22530
   395
            etac impE 1 THEN atac 1 THEN REPEAT (etac allE_Nil 1) THEN
berghofe@22530
   396
            asm_full_simp_tac (simpset_of thy) 1)
berghofe@22530
   397
        end)
berghofe@22530
   398
      end;
berghofe@22530
   399
berghofe@22530
   400
  in
berghofe@22530
   401
    thy |>
berghofe@22530
   402
    ProofContext.init |>
berghofe@22530
   403
    Proof.theorem_i NONE (fn thss => ProofContext.theory (fn thy =>
berghofe@22530
   404
      let
berghofe@22530
   405
        val ctxt = ProofContext.init thy;
berghofe@22530
   406
        val rec_name = space_implode "_" (map Sign.base_name names);
berghofe@22530
   407
        val ind_case_names = RuleCases.case_names induct_cases;
berghofe@24570
   408
        val strong_raw_induct =
berghofe@24570
   409
          mk_proof thy (map (map atomize_intr) thss) |>
berghofe@24747
   410
          InductivePackage.rulify;
berghofe@22530
   411
        val strong_induct =
berghofe@22530
   412
          if length names > 1 then
berghofe@22530
   413
            (strong_raw_induct, [ind_case_names, RuleCases.consumes 0])
berghofe@22530
   414
          else (strong_raw_induct RSN (2, rev_mp),
berghofe@22530
   415
            [ind_case_names, RuleCases.consumes 1]);
berghofe@22530
   416
        val ([strong_induct'], thy') = thy |>
wenzelm@24712
   417
          Sign.add_path rec_name |>
berghofe@22530
   418
          PureThy.add_thms [(("strong_induct", #1 strong_induct), #2 strong_induct)];
berghofe@22530
   419
        val strong_inducts =
berghofe@22530
   420
          ProjectRule.projects ctxt (1 upto length names) strong_induct'
berghofe@22530
   421
      in
berghofe@22530
   422
        thy' |>
berghofe@22530
   423
        PureThy.add_thmss [(("strong_inducts", strong_inducts),
berghofe@22530
   424
          [ind_case_names, RuleCases.consumes 1])] |> snd |>
wenzelm@24712
   425
        Sign.parent_path
berghofe@22530
   426
      end))
berghofe@24570
   427
      (map (map (rulify_term thy #> rpair [])) vc_compat)
berghofe@22530
   428
  end;
berghofe@22530
   429
berghofe@22730
   430
fun prove_eqvt s xatoms thy =
berghofe@22530
   431
  let
berghofe@22530
   432
    val ctxt = ProofContext.init thy;
berghofe@22788
   433
    val ({names, ...}, {raw_induct, intrs, elims, ...}) =
berghofe@22730
   434
      InductivePackage.the_inductive ctxt (Sign.intern_const thy s);
wenzelm@24832
   435
    val raw_induct = atomize_induct ctxt raw_induct;
wenzelm@24832
   436
    val elims = map (atomize_induct ctxt) elims;
berghofe@24570
   437
    val intrs = map atomize_intr intrs;
berghofe@24570
   438
    val monos = InductivePackage.get_monos ctxt;
berghofe@22788
   439
    val intrs' = InductivePackage.unpartition_rules intrs
berghofe@22788
   440
      (map (fn (((s, ths), (_, k)), th) =>
berghofe@22788
   441
           (s, ths ~~ InductivePackage.infer_intro_vars th k ths))
berghofe@22788
   442
         (InductivePackage.partition_rules raw_induct intrs ~~
berghofe@22788
   443
          InductivePackage.arities_of raw_induct ~~ elims));
berghofe@22730
   444
    val atoms' = NominalAtoms.atoms_of thy;
berghofe@22730
   445
    val atoms =
berghofe@22730
   446
      if null xatoms then atoms' else
berghofe@22730
   447
      let val atoms = map (Sign.intern_type thy) xatoms
berghofe@22730
   448
      in
berghofe@22730
   449
        (case duplicates op = atoms of
berghofe@22730
   450
             [] => ()
berghofe@22730
   451
           | xs => error ("Duplicate atoms: " ^ commas xs);
berghofe@22730
   452
         case atoms \\ atoms' of
berghofe@22730
   453
             [] => ()
berghofe@22730
   454
           | xs => error ("No such atoms: " ^ commas xs);
berghofe@22730
   455
         atoms)
berghofe@22730
   456
      end;
berghofe@24570
   457
    val perm_pi_simp = PureThy.get_thms thy (Name "perm_pi_simp");
berghofe@24570
   458
    val eqvt_ss = HOL_basic_ss addsimps
urbanc@24571
   459
      (NominalThmDecls.get_eqvt_thms ctxt @ perm_pi_simp) addsimprocs
berghofe@24570
   460
      [mk_perm_bool_simproc names];
berghofe@22313
   461
    val t = Logic.unvarify (concl_of raw_induct);
berghofe@22313
   462
    val pi = Name.variant (add_term_names (t, [])) "pi";
berghofe@22313
   463
    val ps = map (fst o HOLogic.dest_imp)
berghofe@22313
   464
      (HOLogic.dest_conj (HOLogic.dest_Trueprop t));
berghofe@22788
   465
    fun eqvt_tac th pi (intr, vs) st =
berghofe@22544
   466
      let
berghofe@22544
   467
        fun eqvt_err s = error
berghofe@22544
   468
          ("Could not prove equivariance for introduction rule\n" ^
berghofe@22544
   469
           Sign.string_of_term (theory_of_thm intr)
berghofe@22544
   470
             (Logic.unvarify (prop_of intr)) ^ "\n" ^ s);
berghofe@22788
   471
        val res = SUBPROOF (fn {prems, params, ...} =>
berghofe@22788
   472
          let
berghofe@24570
   473
            val prems' = map (fn th => the_default th (map_thm ctxt
berghofe@24570
   474
              (split_conj (K I) names) (etac conjunct2 1) monos NONE th)) prems;
berghofe@24570
   475
            val prems'' = map (fn th' =>
berghofe@24570
   476
              Simplifier.simplify eqvt_ss (th' RS th)) prems';
berghofe@22788
   477
            val intr' = Drule.cterm_instantiate (map (cterm_of thy) vs ~~
berghofe@22788
   478
               map (cterm_of thy o NominalPackage.mk_perm [] pi o term_of) params)
berghofe@22788
   479
               intr
berghofe@24570
   480
          in (rtac intr' THEN_ALL_NEW (TRY o resolve_tac prems'')) 1
berghofe@22544
   481
          end) ctxt 1 st
berghofe@22544
   482
      in
berghofe@22544
   483
        case (Seq.pull res handle THM (s, _, _) => eqvt_err s) of
berghofe@22544
   484
          NONE => eqvt_err ("Rule does not match goal\n" ^
berghofe@22544
   485
            Sign.string_of_term (theory_of_thm st) (hd (prems_of st)))
berghofe@22544
   486
        | SOME (th, _) => Seq.single th
berghofe@22544
   487
      end;
berghofe@22313
   488
    val thss = map (fn atom =>
berghofe@22313
   489
      let
berghofe@22313
   490
        val pi' = Free (pi, NominalAtoms.mk_permT (Type (atom, [])));
berghofe@22313
   491
        val perm_boolI' = Drule.cterm_instantiate
berghofe@22313
   492
          [(perm_boolI_pi, cterm_of thy pi')] perm_boolI
berghofe@22530
   493
      in map (fn th => zero_var_indexes (th RS mp))
berghofe@22313
   494
        (DatatypeAux.split_conj_thm (Goal.prove_global thy [] []
berghofe@22313
   495
          (HOLogic.mk_Trueprop (foldr1 HOLogic.mk_conj (map (fn p =>
berghofe@22313
   496
            HOLogic.mk_imp (p, list_comb
berghofe@22313
   497
             (apsnd (map (NominalPackage.mk_perm [] pi')) (strip_comb p)))) ps)))
berghofe@22788
   498
          (fn _ => EVERY (rtac raw_induct 1 :: map (fn intr_vs =>
berghofe@22788
   499
              full_simp_tac eqvt_ss 1 THEN
berghofe@22788
   500
              eqvt_tac perm_boolI' pi' intr_vs) intrs'))))
berghofe@22544
   501
      end) atoms
berghofe@22544
   502
  in
berghofe@22544
   503
    fold (fn (name, ths) =>
wenzelm@24712
   504
      Sign.add_path (Sign.base_name name) #>
berghofe@22544
   505
      PureThy.add_thmss [(("eqvt", ths), [NominalThmDecls.eqvt_add])] #> snd #>
wenzelm@24712
   506
      Sign.parent_path) (names ~~ transp thss) thy
berghofe@22544
   507
  end;
berghofe@22313
   508
berghofe@22313
   509
berghofe@22313
   510
(* outer syntax *)
berghofe@22313
   511
berghofe@22313
   512
local structure P = OuterParse and K = OuterKeyword in
berghofe@22313
   513
wenzelm@24867
   514
val _ = OuterSyntax.keywords ["avoids"];
wenzelm@24867
   515
wenzelm@24867
   516
val _ =
berghofe@22313
   517
  OuterSyntax.command "nominal_inductive"
berghofe@22530
   518
    "prove equivariance and strong induction theorem for inductive predicate involving nominal datatypes" K.thy_goal
berghofe@22530
   519
    (P.name -- Scan.optional (P.$$$ "avoids" |-- P.and_list1 (P.name --
berghofe@22530
   520
      (P.$$$ ":" |-- Scan.repeat1 P.name))) [] >> (fn (name, avoids) =>
berghofe@22730
   521
        Toplevel.print o Toplevel.theory_to_proof (prove_strong_ind name avoids)));
berghofe@22313
   522
wenzelm@24867
   523
val _ =
berghofe@22530
   524
  OuterSyntax.command "equivariance"
berghofe@22530
   525
    "prove equivariance for inductive predicate involving nominal datatypes" K.thy_decl
berghofe@22730
   526
    (P.name -- Scan.optional (P.$$$ "[" |-- P.list1 P.name --| P.$$$ "]") [] >>
berghofe@22730
   527
      (fn (name, atoms) => Toplevel.theory (prove_eqvt name atoms)));
berghofe@22530
   528
berghofe@22313
   529
end;
berghofe@22313
   530
berghofe@22313
   531
end