src/HOL/Library/Old_SMT/old_z3_proof_reconstruction.ML
changeset 58058 1a0b18176548
parent 58057 883f3c4c928e
child 58059 4e477dcd050a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/Old_SMT/old_z3_proof_reconstruction.ML	Thu Aug 28 00:40:38 2014 +0200
@@ -0,0 +1,888 @@
+(*  Title:      HOL/Library/Old_SMT/old_z3_proof_reconstruction.ML
+    Author:     Sascha Boehme, TU Muenchen
+
+Proof reconstruction for proofs found by Z3.
+*)
+
+signature OLD_Z3_PROOF_RECONSTRUCTION =
+sig
+  val add_z3_rule: thm -> Context.generic -> Context.generic
+  val reconstruct: Proof.context -> Old_SMT_Translate.recon -> string list -> int list * thm
+end
+
+structure Old_Z3_Proof_Reconstruction: OLD_Z3_PROOF_RECONSTRUCTION =
+struct
+
+
+fun z3_exn msg = raise Old_SMT_Failure.SMT (Old_SMT_Failure.Other_Failure
+  ("Z3 proof reconstruction: " ^ msg))
+
+
+
+(* net of schematic rules *)
+
+local
+  val description = "declaration of Z3 proof rules"
+
+  val eq = Thm.eq_thm
+
+  structure Old_Z3_Rules = Generic_Data
+  (
+    type T = thm Net.net
+    val empty = Net.empty
+    val extend = I
+    val merge = Net.merge eq
+  )
+
+  fun prep context =
+    `Thm.prop_of o rewrite_rule (Context.proof_of context) [Old_Z3_Proof_Literals.rewrite_true]
+
+  fun ins thm context =
+    context |> Old_Z3_Rules.map (fn net => Net.insert_term eq (prep context thm) net handle Net.INSERT => net)
+  fun rem thm context =
+    context |> Old_Z3_Rules.map (fn net => Net.delete_term eq (prep context thm) net handle Net.DELETE => net)
+
+  val add = Thm.declaration_attribute ins
+  val del = Thm.declaration_attribute rem
+in
+
+val add_z3_rule = ins
+
+fun by_schematic_rule ctxt ct =
+  the (Old_Z3_Proof_Tools.net_instance (Old_Z3_Rules.get (Context.Proof ctxt)) ct)
+
+val _ = Theory.setup
+ (Attrib.setup @{binding z3_rule} (Attrib.add_del add del) description #>
+  Global_Theory.add_thms_dynamic (@{binding z3_rule}, Net.content o Old_Z3_Rules.get))
+
+end
+
+
+
+(* proof tools *)
+
+fun named ctxt name prover ct =
+  let val _ = Old_SMT_Config.trace_msg ctxt I ("Z3: trying " ^ name ^ " ...")
+  in prover ct end
+
+fun NAMED ctxt name tac i st =
+  let val _ = Old_SMT_Config.trace_msg ctxt I ("Z3: trying " ^ name ^ " ...")
+  in tac i st end
+
+fun pretty_goal ctxt thms t =
+  [Pretty.block [Pretty.str "proposition: ", Syntax.pretty_term ctxt t]]
+  |> not (null thms) ? cons (Pretty.big_list "assumptions:"
+       (map (Display.pretty_thm ctxt) thms))
+
+fun try_apply ctxt thms =
+  let
+    fun try_apply_err ct = Pretty.string_of (Pretty.chunks [
+      Pretty.big_list ("Z3 found a proof," ^
+        " but proof reconstruction failed at the following subgoal:")
+        (pretty_goal ctxt thms (Thm.term_of ct)),
+      Pretty.str ("Declaring a rule as [z3_rule] might solve this problem.")])
+
+    fun apply [] ct = error (try_apply_err ct)
+      | apply (prover :: provers) ct =
+          (case try prover ct of
+            SOME thm => (Old_SMT_Config.trace_msg ctxt I "Z3: succeeded"; thm)
+          | NONE => apply provers ct)
+
+    fun schematic_label full = "schematic rules" |> full ? suffix " (full)"
+    fun schematic ctxt full ct =
+      ct
+      |> full ? fold_rev (curry Drule.mk_implies o Thm.cprop_of) thms
+      |> named ctxt (schematic_label full) (by_schematic_rule ctxt)
+      |> fold Thm.elim_implies thms
+
+  in apply o cons (schematic ctxt false) o cons (schematic ctxt true) end
+
+local
+  val rewr_if =
+    @{lemma "(if P then Q1 else Q2) = ((P --> Q1) & (~P --> Q2))" by simp}
+in
+
+fun HOL_fast_tac ctxt =
+  Classical.fast_tac (put_claset HOL_cs ctxt)
+
+fun simp_fast_tac ctxt =
+  Simplifier.simp_tac (put_simpset HOL_ss ctxt addsimps [rewr_if])
+  THEN_ALL_NEW HOL_fast_tac ctxt
+
+end
+
+
+
+(* theorems and proofs *)
+
+(** theorem incarnations **)
+
+datatype theorem =
+  Thm of thm | (* theorem without special features *)
+  MetaEq of thm | (* meta equality "t == s" *)
+  Literals of thm * Old_Z3_Proof_Literals.littab
+    (* "P1 & ... & Pn" and table of all literals P1, ..., Pn *)
+
+fun thm_of (Thm thm) = thm
+  | thm_of (MetaEq thm) = thm COMP @{thm meta_eq_to_obj_eq}
+  | thm_of (Literals (thm, _)) = thm
+
+fun meta_eq_of (MetaEq thm) = thm
+  | meta_eq_of p = mk_meta_eq (thm_of p)
+
+fun literals_of (Literals (_, lits)) = lits
+  | literals_of p = Old_Z3_Proof_Literals.make_littab [thm_of p]
+
+
+
+(** core proof rules **)
+
+(* assumption *)
+
+local
+  val remove_trigger = mk_meta_eq @{thm trigger_def}
+  val remove_weight = mk_meta_eq @{thm weight_def}
+  val remove_fun_app = mk_meta_eq @{thm fun_app_def}
+
+  fun rewrite_conv _ [] = Conv.all_conv
+    | rewrite_conv ctxt eqs = Simplifier.full_rewrite (empty_simpset ctxt addsimps eqs)
+
+  val prep_rules = [@{thm Let_def}, remove_trigger, remove_weight,
+    remove_fun_app, Old_Z3_Proof_Literals.rewrite_true]
+
+  fun rewrite _ [] = I
+    | rewrite ctxt eqs = Conv.fconv_rule (rewrite_conv ctxt eqs)
+
+  fun lookup_assm assms_net ct =
+    Old_Z3_Proof_Tools.net_instances assms_net ct
+    |> map (fn ithm as (_, thm) => (ithm, Thm.cprop_of thm aconvc ct))
+in
+
+fun add_asserted outer_ctxt rewrite_rules assms asserted ctxt =
+  let
+    val eqs = map (rewrite ctxt [Old_Z3_Proof_Literals.rewrite_true]) rewrite_rules
+    val eqs' = union Thm.eq_thm eqs prep_rules
+
+    val assms_net =
+      assms
+      |> map (apsnd (rewrite ctxt eqs'))
+      |> map (apsnd (Conv.fconv_rule Thm.eta_conversion))
+      |> Old_Z3_Proof_Tools.thm_net_of snd 
+
+    fun revert_conv ctxt = rewrite_conv ctxt eqs' then_conv Thm.eta_conversion
+
+    fun assume thm ctxt =
+      let
+        val ct = Thm.cprem_of thm 1
+        val (thm', ctxt') = yield_singleton Assumption.add_assumes ct ctxt
+      in (Thm.implies_elim thm thm', ctxt') end
+
+    fun add1 idx thm1 ((i, th), exact) ((is, thms), (ctxt, ptab)) =
+      let
+        val (thm, ctxt') =
+          if exact then (Thm.implies_elim thm1 th, ctxt)
+          else assume thm1 ctxt
+        val thms' = if exact then thms else th :: thms
+      in 
+        ((insert (op =) i is, thms'),
+          (ctxt', Inttab.update (idx, Thm thm) ptab))
+      end
+
+    fun add (idx, ct) (cx as ((is, thms), (ctxt, ptab))) =
+      let
+        val thm1 = 
+          Thm.trivial ct
+          |> Conv.fconv_rule (Conv.arg1_conv (revert_conv outer_ctxt))
+        val thm2 = singleton (Variable.export ctxt outer_ctxt) thm1
+      in
+        (case lookup_assm assms_net (Thm.cprem_of thm2 1) of
+          [] =>
+            let val (thm, ctxt') = assume thm1 ctxt
+            in ((is, thms), (ctxt', Inttab.update (idx, Thm thm) ptab)) end
+        | ithms => fold (add1 idx thm1) ithms cx)
+      end
+  in fold add asserted (([], []), (ctxt, Inttab.empty)) end
+
+end
+
+
+(* P = Q ==> P ==> Q   or   P --> Q ==> P ==> Q *)
+local
+  val precomp = Old_Z3_Proof_Tools.precompose2
+  val comp = Old_Z3_Proof_Tools.compose
+
+  val meta_iffD1 = @{lemma "P == Q ==> P ==> (Q::bool)" by simp}
+  val meta_iffD1_c = precomp Thm.dest_binop meta_iffD1
+
+  val iffD1_c = precomp (Thm.dest_binop o Thm.dest_arg) @{thm iffD1}
+  val mp_c = precomp (Thm.dest_binop o Thm.dest_arg) @{thm mp}
+in
+fun mp (MetaEq thm) p = Thm (Thm.implies_elim (comp meta_iffD1_c thm) p)
+  | mp p_q p = 
+      let
+        val pq = thm_of p_q
+        val thm = comp iffD1_c pq handle THM _ => comp mp_c pq
+      in Thm (Thm.implies_elim thm p) end
+end
+
+
+(* and_elim:     P1 & ... & Pn ==> Pi *)
+(* not_or_elim:  ~(P1 | ... | Pn) ==> ~Pi *)
+local
+  fun is_sublit conj t = Old_Z3_Proof_Literals.exists_lit conj (fn u => u aconv t)
+
+  fun derive conj t lits idx ptab =
+    let
+      val lit = the (Old_Z3_Proof_Literals.get_first_lit (is_sublit conj t) lits)
+      val ls = Old_Z3_Proof_Literals.explode conj false false [t] lit
+      val lits' = fold Old_Z3_Proof_Literals.insert_lit ls
+        (Old_Z3_Proof_Literals.delete_lit lit lits)
+
+      fun upd thm = Literals (thm_of thm, lits')
+      val ptab' = Inttab.map_entry idx upd ptab
+    in (the (Old_Z3_Proof_Literals.lookup_lit lits' t), ptab') end
+
+  fun lit_elim conj (p, idx) ct ptab =
+    let val lits = literals_of p
+    in
+      (case Old_Z3_Proof_Literals.lookup_lit lits (Old_SMT_Utils.term_of ct) of
+        SOME lit => (Thm lit, ptab)
+      | NONE => apfst Thm (derive conj (Old_SMT_Utils.term_of ct) lits idx ptab))
+    end
+in
+val and_elim = lit_elim true
+val not_or_elim = lit_elim false
+end
+
+
+(* P1, ..., Pn |- False ==> |- ~P1 | ... | ~Pn *)
+local
+  fun step lit thm =
+    Thm.implies_elim (Thm.implies_intr (Thm.cprop_of lit) thm) lit
+  val explode_disj = Old_Z3_Proof_Literals.explode false false false
+  fun intro hyps thm th = fold step (explode_disj hyps th) thm
+
+  fun dest_ccontr ct = [Thm.dest_arg (Thm.dest_arg (Thm.dest_arg1 ct))]
+  val ccontr = Old_Z3_Proof_Tools.precompose dest_ccontr @{thm ccontr}
+in
+fun lemma thm ct =
+  let
+    val cu = Old_Z3_Proof_Literals.negate (Thm.dest_arg ct)
+    val hyps = map_filter (try HOLogic.dest_Trueprop) (Thm.hyps_of thm)
+    val th = Old_Z3_Proof_Tools.under_assumption (intro hyps thm) cu
+  in Thm (Old_Z3_Proof_Tools.compose ccontr th) end
+end
+
+
+(* \/{P1, ..., Pn, Q1, ..., Qn}, ~P1, ..., ~Pn ==> \/{Q1, ..., Qn} *)
+local
+  val explode_disj = Old_Z3_Proof_Literals.explode false true false
+  val join_disj = Old_Z3_Proof_Literals.join false
+  fun unit thm thms th =
+    let
+      val t = @{const Not} $ Old_SMT_Utils.prop_of thm
+      val ts = map Old_SMT_Utils.prop_of thms
+    in
+      join_disj (Old_Z3_Proof_Literals.make_littab (thms @ explode_disj ts th)) t
+    end
+
+  fun dest_arg2 ct = Thm.dest_arg (Thm.dest_arg ct)
+  fun dest ct = pairself dest_arg2 (Thm.dest_binop ct)
+  val contrapos =
+    Old_Z3_Proof_Tools.precompose2 dest @{lemma "(~P ==> ~Q) ==> Q ==> P" by fast}
+in
+fun unit_resolution thm thms ct =
+  Old_Z3_Proof_Literals.negate (Thm.dest_arg ct)
+  |> Old_Z3_Proof_Tools.under_assumption (unit thm thms)
+  |> Thm o Old_Z3_Proof_Tools.discharge thm o Old_Z3_Proof_Tools.compose contrapos
+end
+
+
+(* P ==> P == True   or   P ==> P == False *)
+local
+  val iff1 = @{lemma "P ==> P == (~ False)" by simp}
+  val iff2 = @{lemma "~P ==> P == False" by simp}
+in
+fun iff_true thm = MetaEq (thm COMP iff1)
+fun iff_false thm = MetaEq (thm COMP iff2)
+end
+
+
+(* distributivity of | over & *)
+fun distributivity ctxt = Thm o try_apply ctxt [] [
+  named ctxt "fast" (Old_Z3_Proof_Tools.by_tac ctxt (HOL_fast_tac ctxt))]
+    (* FIXME: not very well tested *)
+
+
+(* Tseitin-like axioms *)
+local
+  val disjI1 = @{lemma "(P ==> Q) ==> ~P | Q" by fast}
+  val disjI2 = @{lemma "(~P ==> Q) ==> P | Q" by fast}
+  val disjI3 = @{lemma "(~Q ==> P) ==> P | Q" by fast}
+  val disjI4 = @{lemma "(Q ==> P) ==> P | ~Q" by fast}
+
+  fun prove' conj1 conj2 ct2 thm =
+    let
+      val littab =
+        Old_Z3_Proof_Literals.explode conj1 true (conj1 <> conj2) [] thm
+        |> cons Old_Z3_Proof_Literals.true_thm
+        |> Old_Z3_Proof_Literals.make_littab
+    in Old_Z3_Proof_Literals.join conj2 littab (Thm.term_of ct2) end
+
+  fun prove rule (ct1, conj1) (ct2, conj2) =
+    Old_Z3_Proof_Tools.under_assumption (prove' conj1 conj2 ct2) ct1 COMP rule
+
+  fun prove_def_axiom ct =
+    let val (ct1, ct2) = Thm.dest_binop (Thm.dest_arg ct)
+    in
+      (case Thm.term_of ct1 of
+        @{const Not} $ (@{const HOL.conj} $ _ $ _) =>
+          prove disjI1 (Thm.dest_arg ct1, true) (ct2, true)
+      | @{const HOL.conj} $ _ $ _ =>
+          prove disjI3 (Old_Z3_Proof_Literals.negate ct2, false) (ct1, true)
+      | @{const Not} $ (@{const HOL.disj} $ _ $ _) =>
+          prove disjI3 (Old_Z3_Proof_Literals.negate ct2, false) (ct1, false)
+      | @{const HOL.disj} $ _ $ _ =>
+          prove disjI2 (Old_Z3_Proof_Literals.negate ct1, false) (ct2, true)
+      | Const (@{const_name distinct}, _) $ _ =>
+          let
+            fun dis_conv cv = Conv.arg_conv (Conv.arg1_conv cv)
+            val unfold_dis_conv = dis_conv Old_Z3_Proof_Tools.unfold_distinct_conv
+            fun prv cu =
+              let val (cu1, cu2) = Thm.dest_binop (Thm.dest_arg cu)
+              in prove disjI4 (Thm.dest_arg cu2, true) (cu1, true) end
+          in Old_Z3_Proof_Tools.with_conv unfold_dis_conv prv ct end
+      | @{const Not} $ (Const (@{const_name distinct}, _) $ _) =>
+          let
+            fun dis_conv cv = Conv.arg_conv (Conv.arg1_conv (Conv.arg_conv cv))
+            val unfold_dis_conv = dis_conv Old_Z3_Proof_Tools.unfold_distinct_conv
+            fun prv cu =
+              let val (cu1, cu2) = Thm.dest_binop (Thm.dest_arg cu)
+              in prove disjI1 (Thm.dest_arg cu1, true) (cu2, true) end
+          in Old_Z3_Proof_Tools.with_conv unfold_dis_conv prv ct end
+      | _ => raise CTERM ("prove_def_axiom", [ct]))
+    end
+in
+fun def_axiom ctxt = Thm o try_apply ctxt [] [
+  named ctxt "conj/disj/distinct" prove_def_axiom,
+  Old_Z3_Proof_Tools.by_abstraction 0 (true, false) ctxt [] (fn ctxt' =>
+    named ctxt' "simp+fast" (Old_Z3_Proof_Tools.by_tac ctxt (simp_fast_tac ctxt')))]
+end
+
+
+(* local definitions *)
+local
+  val intro_rules = [
+    @{lemma "n == P ==> (~n | P) & (n | ~P)" by simp},
+    @{lemma "n == (if P then s else t) ==> (~P | n = s) & (P | n = t)"
+      by simp},
+    @{lemma "n == P ==> n = P" by (rule meta_eq_to_obj_eq)} ]
+
+  val apply_rules = [
+    @{lemma "(~n | P) & (n | ~P) ==> P == n" by (atomize(full)) fast},
+    @{lemma "(~P | n = s) & (P | n = t) ==> (if P then s else t) == n"
+      by (atomize(full)) fastforce} ]
+
+  val inst_rule = Old_Z3_Proof_Tools.match_instantiate Thm.dest_arg
+
+  fun apply_rule ct =
+    (case get_first (try (inst_rule ct)) intro_rules of
+      SOME thm => thm
+    | NONE => raise CTERM ("intro_def", [ct]))
+in
+fun intro_def ct = Old_Z3_Proof_Tools.make_hyp_def (apply_rule ct) #>> Thm
+
+fun apply_def thm =
+  get_first (try (fn rule => MetaEq (thm COMP rule))) apply_rules
+  |> the_default (Thm thm)
+end
+
+
+(* negation normal form *)
+local
+  val quant_rules1 = ([
+    @{lemma "(!!x. P x == Q) ==> ALL x. P x == Q" by simp},
+    @{lemma "(!!x. P x == Q) ==> EX x. P x == Q" by simp}], [
+    @{lemma "(!!x. P x == Q x) ==> ALL x. P x == ALL x. Q x" by simp},
+    @{lemma "(!!x. P x == Q x) ==> EX x. P x == EX x. Q x" by simp}])
+
+  val quant_rules2 = ([
+    @{lemma "(!!x. ~P x == Q) ==> ~(ALL x. P x) == Q" by simp},
+    @{lemma "(!!x. ~P x == Q) ==> ~(EX x. P x) == Q" by simp}], [
+    @{lemma "(!!x. ~P x == Q x) ==> ~(ALL x. P x) == EX x. Q x" by simp},
+    @{lemma "(!!x. ~P x == Q x) ==> ~(EX x. P x) == ALL x. Q x" by simp}])
+
+  fun nnf_quant_tac thm (qs as (qs1, qs2)) i st = (
+    rtac thm ORELSE'
+    (match_tac qs1 THEN' nnf_quant_tac thm qs) ORELSE'
+    (match_tac qs2 THEN' nnf_quant_tac thm qs)) i st
+
+  fun nnf_quant_tac_varified vars eq =
+    nnf_quant_tac (Old_Z3_Proof_Tools.varify vars eq)
+
+  fun nnf_quant ctxt vars qs p ct =
+    Old_Z3_Proof_Tools.as_meta_eq ct
+    |> Old_Z3_Proof_Tools.by_tac ctxt (nnf_quant_tac_varified vars (meta_eq_of p) qs)
+
+  fun prove_nnf ctxt = try_apply ctxt [] [
+    named ctxt "conj/disj" Old_Z3_Proof_Literals.prove_conj_disj_eq,
+    Old_Z3_Proof_Tools.by_abstraction 0 (true, false) ctxt [] (fn ctxt' =>
+      named ctxt' "simp+fast" (Old_Z3_Proof_Tools.by_tac ctxt' (simp_fast_tac ctxt')))]
+in
+fun nnf ctxt vars ps ct =
+  (case Old_SMT_Utils.term_of ct of
+    _ $ (l as Const _ $ Abs _) $ (r as Const _ $ Abs _) =>
+      if l aconv r
+      then MetaEq (Thm.reflexive (Thm.dest_arg (Thm.dest_arg ct)))
+      else MetaEq (nnf_quant ctxt vars quant_rules1 (hd ps) ct)
+  | _ $ (@{const Not} $ (Const _ $ Abs _)) $ (Const _ $ Abs _) =>
+      MetaEq (nnf_quant ctxt vars quant_rules2 (hd ps) ct)
+  | _ =>
+      let
+        val nnf_rewr_conv = Conv.arg_conv (Conv.arg_conv
+          (Old_Z3_Proof_Tools.unfold_eqs ctxt
+            (map (Thm.symmetric o meta_eq_of) ps)))
+      in Thm (Old_Z3_Proof_Tools.with_conv nnf_rewr_conv (prove_nnf ctxt) ct) end)
+end
+
+
+
+(** equality proof rules **)
+
+(* |- t = t *)
+fun refl ct = MetaEq (Thm.reflexive (Thm.dest_arg (Thm.dest_arg ct)))
+
+
+(* s = t ==> t = s *)
+local
+  val symm_rule = @{lemma "s = t ==> t == s" by simp}
+in
+fun symm (MetaEq thm) = MetaEq (Thm.symmetric thm)
+  | symm p = MetaEq (thm_of p COMP symm_rule)
+end
+
+
+(* s = t ==> t = u ==> s = u *)
+local
+  val trans1 = @{lemma "s == t ==> t =  u ==> s == u" by simp}
+  val trans2 = @{lemma "s =  t ==> t == u ==> s == u" by simp}
+  val trans3 = @{lemma "s =  t ==> t =  u ==> s == u" by simp}
+in
+fun trans (MetaEq thm1) (MetaEq thm2) = MetaEq (Thm.transitive thm1 thm2)
+  | trans (MetaEq thm) q = MetaEq (thm_of q COMP (thm COMP trans1))
+  | trans p (MetaEq thm) = MetaEq (thm COMP (thm_of p COMP trans2))
+  | trans p q = MetaEq (thm_of q COMP (thm_of p COMP trans3))
+end
+
+
+(* t1 = s1 ==> ... ==> tn = sn ==> f t1 ... tn = f s1 .. sn
+   (reflexive antecendents are droppped) *)
+local
+  exception MONO
+
+  fun prove_refl (ct, _) = Thm.reflexive ct
+  fun prove_comb f g cp =
+    let val ((ct1, ct2), (cu1, cu2)) = pairself Thm.dest_comb cp
+    in Thm.combination (f (ct1, cu1)) (g (ct2, cu2)) end
+  fun prove_arg f = prove_comb prove_refl f
+
+  fun prove f cp = prove_comb (prove f) f cp handle CTERM _ => prove_refl cp
+
+  fun prove_nary is_comb f =
+    let
+      fun prove (cp as (ct, _)) = f cp handle MONO =>
+        if is_comb (Thm.term_of ct)
+        then prove_comb (prove_arg prove) prove cp
+        else prove_refl cp
+    in prove end
+
+  fun prove_list f n cp =
+    if n = 0 then prove_refl cp
+    else prove_comb (prove_arg f) (prove_list f (n-1)) cp
+
+  fun with_length f (cp as (cl, _)) =
+    f (length (HOLogic.dest_list (Thm.term_of cl))) cp
+
+  fun prove_distinct f = prove_arg (with_length (prove_list f))
+
+  fun prove_eq exn lookup cp =
+    (case lookup (Logic.mk_equals (pairself Thm.term_of cp)) of
+      SOME eq => eq
+    | NONE => if exn then raise MONO else prove_refl cp)
+  
+  val prove_exn = prove_eq true
+  and prove_safe = prove_eq false
+
+  fun mono f (cp as (cl, _)) =
+    (case Term.head_of (Thm.term_of cl) of
+      @{const HOL.conj} => prove_nary Old_Z3_Proof_Literals.is_conj (prove_exn f)
+    | @{const HOL.disj} => prove_nary Old_Z3_Proof_Literals.is_disj (prove_exn f)
+    | Const (@{const_name distinct}, _) => prove_distinct (prove_safe f)
+    | _ => prove (prove_safe f)) cp
+in
+fun monotonicity eqs ct =
+  let
+    fun and_symmetric (t, thm) = [(t, thm), (t, Thm.symmetric thm)]
+    val teqs = maps (and_symmetric o `Thm.prop_of o meta_eq_of) eqs
+    val lookup = AList.lookup (op aconv) teqs
+    val cp = Thm.dest_binop (Thm.dest_arg ct)
+  in MetaEq (prove_exn lookup cp handle MONO => mono lookup cp) end
+end
+
+
+(* |- f a b = f b a (where f is equality) *)
+local
+  val rule = @{lemma "a = b == b = a" by (atomize(full)) (rule eq_commute)}
+in
+fun commutativity ct =
+  MetaEq (Old_Z3_Proof_Tools.match_instantiate I
+    (Old_Z3_Proof_Tools.as_meta_eq ct) rule)
+end
+
+
+
+(** quantifier proof rules **)
+
+(* P ?x = Q ?x ==> (ALL x. P x) = (ALL x. Q x)
+   P ?x = Q ?x ==> (EX x. P x) = (EX x. Q x)    *)
+local
+  val rules = [
+    @{lemma "(!!x. P x == Q x) ==> (ALL x. P x) == (ALL x. Q x)" by simp},
+    @{lemma "(!!x. P x == Q x) ==> (EX x. P x) == (EX x. Q x)" by simp}]
+in
+fun quant_intro ctxt vars p ct =
+  let
+    val thm = meta_eq_of p
+    val rules' = Old_Z3_Proof_Tools.varify vars thm :: rules
+    val cu = Old_Z3_Proof_Tools.as_meta_eq ct
+    val tac = REPEAT_ALL_NEW (match_tac rules')
+  in MetaEq (Old_Z3_Proof_Tools.by_tac ctxt tac cu) end
+end
+
+
+(* |- ((ALL x. P x) | Q) = (ALL x. P x | Q) *)
+fun pull_quant ctxt = Thm o try_apply ctxt [] [
+  named ctxt "fast" (Old_Z3_Proof_Tools.by_tac ctxt (HOL_fast_tac ctxt))]
+    (* FIXME: not very well tested *)
+
+
+(* |- (ALL x. P x & Q x) = ((ALL x. P x) & (ALL x. Q x)) *)
+fun push_quant ctxt = Thm o try_apply ctxt [] [
+  named ctxt "fast" (Old_Z3_Proof_Tools.by_tac ctxt (HOL_fast_tac ctxt))]
+    (* FIXME: not very well tested *)
+
+
+(* |- (ALL x1 ... xn y1 ... yn. P x1 ... xn) = (ALL x1 ... xn. P x1 ... xn) *)
+local
+  val elim_all = @{lemma "P = Q ==> (ALL x. P) = Q" by fast}
+  val elim_ex = @{lemma "P = Q ==> (EX x. P) = Q" by fast}
+
+  fun elim_unused_tac i st = (
+    match_tac [@{thm refl}]
+    ORELSE' (match_tac [elim_all, elim_ex] THEN' elim_unused_tac)
+    ORELSE' (
+      match_tac [@{thm iff_allI}, @{thm iff_exI}]
+      THEN' elim_unused_tac)) i st
+in
+
+fun elim_unused_vars ctxt = Thm o Old_Z3_Proof_Tools.by_tac ctxt elim_unused_tac
+
+end
+
+
+(* |- (ALL x1 ... xn. ~(x1 = t1 & ... xn = tn) | P x1 ... xn) = P t1 ... tn *)
+fun dest_eq_res ctxt = Thm o try_apply ctxt [] [
+  named ctxt "fast" (Old_Z3_Proof_Tools.by_tac ctxt (HOL_fast_tac ctxt))]
+    (* FIXME: not very well tested *)
+
+
+(* |- ~(ALL x1...xn. P x1...xn) | P a1...an *)
+local
+  val rule = @{lemma "~ P x | Q ==> ~(ALL x. P x) | Q" by fast}
+in
+fun quant_inst ctxt = Thm o Old_Z3_Proof_Tools.by_tac ctxt (
+  REPEAT_ALL_NEW (match_tac [rule])
+  THEN' rtac @{thm excluded_middle})
+end
+
+
+(* |- (EX x. P x) = P c     |- ~(ALL x. P x) = ~ P c *)
+local
+  val forall =
+    Old_SMT_Utils.mk_const_pat @{theory} @{const_name Pure.all}
+      (Old_SMT_Utils.destT1 o Old_SMT_Utils.destT1)
+  fun mk_forall cv ct =
+    Thm.apply (Old_SMT_Utils.instT' cv forall) (Thm.lambda cv ct)
+
+  fun get_vars f mk pred ctxt t =
+    Term.fold_aterms f t []
+    |> map_filter (fn v =>
+         if pred v then SOME (Old_SMT_Utils.certify ctxt (mk v)) else NONE)
+
+  fun close vars f ct ctxt =
+    let
+      val frees_of = get_vars Term.add_frees Free (member (op =) vars o fst)
+      val vs = frees_of ctxt (Thm.term_of ct)
+      val (thm, ctxt') = f (fold_rev mk_forall vs ct) ctxt
+      val vars_of = get_vars Term.add_vars Var (K true) ctxt'
+    in (Thm.instantiate ([], vars_of (Thm.prop_of thm) ~~ vs) thm, ctxt') end
+
+  val sk_rules = @{lemma
+    "c = (SOME x. P x) ==> (EX x. P x) = P c"
+    "c = (SOME x. ~P x) ==> (~(ALL x. P x)) = (~P c)"
+    by (metis someI_ex)+}
+in
+
+fun skolemize vars =
+  apfst Thm oo close vars (yield_singleton Assumption.add_assumes)
+
+fun discharge_sk_tac i st = (
+  rtac @{thm trans} i
+  THEN resolve_tac sk_rules i
+  THEN (rtac @{thm refl} ORELSE' discharge_sk_tac) (i+1)
+  THEN rtac @{thm refl} i) st
+
+end
+
+
+
+(** theory proof rules **)
+
+(* theory lemmas: linear arithmetic, arrays *)
+fun th_lemma ctxt simpset thms = Thm o try_apply ctxt thms [
+  Old_Z3_Proof_Tools.by_abstraction 0 (false, true) ctxt thms (fn ctxt' =>
+    Old_Z3_Proof_Tools.by_tac ctxt' (
+      NAMED ctxt' "arith" (Arith_Data.arith_tac ctxt')
+      ORELSE' NAMED ctxt' "simp+arith" (
+        Simplifier.asm_full_simp_tac (put_simpset simpset ctxt')
+        THEN_ALL_NEW Arith_Data.arith_tac ctxt')))]
+
+
+(* rewriting: prove equalities:
+     * ACI of conjunction/disjunction
+     * contradiction, excluded middle
+     * logical rewriting rules (for negation, implication, equivalence,
+         distinct)
+     * normal forms for polynoms (integer/real arithmetic)
+     * quantifier elimination over linear arithmetic
+     * ... ? **)
+local
+  fun spec_meta_eq_of thm =
+    (case try (fn th => th RS @{thm spec}) thm of
+      SOME thm' => spec_meta_eq_of thm'
+    | NONE => mk_meta_eq thm)
+
+  fun prep (Thm thm) = spec_meta_eq_of thm
+    | prep (MetaEq thm) = thm
+    | prep (Literals (thm, _)) = spec_meta_eq_of thm
+
+  fun unfold_conv ctxt ths =
+    Conv.arg_conv (Conv.binop_conv (Old_Z3_Proof_Tools.unfold_eqs ctxt
+      (map prep ths)))
+
+  fun with_conv _ [] prv = prv
+    | with_conv ctxt ths prv =
+        Old_Z3_Proof_Tools.with_conv (unfold_conv ctxt ths) prv
+
+  val unfold_conv =
+    Conv.arg_conv (Conv.binop_conv
+      (Conv.try_conv Old_Z3_Proof_Tools.unfold_distinct_conv))
+  val prove_conj_disj_eq =
+    Old_Z3_Proof_Tools.with_conv unfold_conv Old_Z3_Proof_Literals.prove_conj_disj_eq
+
+  fun declare_hyps ctxt thm =
+    (thm, snd (Assumption.add_assumes (#hyps (Thm.crep_thm thm)) ctxt))
+in
+
+val abstraction_depth = 3
+  (*
+    This value was chosen large enough to potentially catch exceptions,
+    yet small enough to not cause too much harm.  The value might be
+    increased in the future, if reconstructing 'rewrite' fails on problems
+    that get too much abstracted to be reconstructable.
+  *)
+
+fun rewrite simpset ths ct ctxt =
+  apfst Thm (declare_hyps ctxt (with_conv ctxt ths (try_apply ctxt [] [
+    named ctxt "conj/disj/distinct" prove_conj_disj_eq,
+    named ctxt "pull-ite" Old_Z3_Proof_Methods.prove_ite ctxt,
+    Old_Z3_Proof_Tools.by_abstraction 0 (true, false) ctxt [] (fn ctxt' =>
+      Old_Z3_Proof_Tools.by_tac ctxt' (
+        NAMED ctxt' "simp (logic)" (Simplifier.simp_tac (put_simpset simpset ctxt'))
+        THEN_ALL_NEW NAMED ctxt' "fast (logic)" (fast_tac ctxt'))),
+    Old_Z3_Proof_Tools.by_abstraction 0 (false, true) ctxt [] (fn ctxt' =>
+      Old_Z3_Proof_Tools.by_tac ctxt' (
+        (rtac @{thm iff_allI} ORELSE' K all_tac)
+        THEN' NAMED ctxt' "simp (theory)" (Simplifier.simp_tac (put_simpset simpset ctxt'))
+        THEN_ALL_NEW (
+          NAMED ctxt' "fast (theory)" (HOL_fast_tac ctxt')
+          ORELSE' NAMED ctxt' "arith (theory)" (Arith_Data.arith_tac ctxt')))),
+    Old_Z3_Proof_Tools.by_abstraction 0 (true, true) ctxt [] (fn ctxt' =>
+      Old_Z3_Proof_Tools.by_tac ctxt' (
+        (rtac @{thm iff_allI} ORELSE' K all_tac)
+        THEN' NAMED ctxt' "simp (full)" (Simplifier.simp_tac (put_simpset simpset ctxt'))
+        THEN_ALL_NEW (
+          NAMED ctxt' "fast (full)" (HOL_fast_tac ctxt')
+          ORELSE' NAMED ctxt' "arith (full)" (Arith_Data.arith_tac ctxt')))),
+    named ctxt "injectivity" (Old_Z3_Proof_Methods.prove_injectivity ctxt),
+    Old_Z3_Proof_Tools.by_abstraction abstraction_depth (true, true) ctxt []
+      (fn ctxt' =>
+        Old_Z3_Proof_Tools.by_tac ctxt' (
+          (rtac @{thm iff_allI} ORELSE' K all_tac)
+          THEN' NAMED ctxt' "simp (deepen)" (Simplifier.simp_tac (put_simpset simpset ctxt'))
+          THEN_ALL_NEW (
+            NAMED ctxt' "fast (deepen)" (HOL_fast_tac ctxt')
+            ORELSE' NAMED ctxt' "arith (deepen)" (Arith_Data.arith_tac
+              ctxt'))))]) ct))
+
+end
+
+
+
+(* proof reconstruction *)
+
+(** tracing and checking **)
+
+fun trace_before ctxt idx = Old_SMT_Config.trace_msg ctxt (fn r =>
+  "Z3: #" ^ string_of_int idx ^ ": " ^ Old_Z3_Proof_Parser.string_of_rule r)
+
+fun check_after idx r ps ct (p, (ctxt, _)) =
+  if not (Config.get ctxt Old_SMT_Config.trace) then ()
+  else
+    let val thm = thm_of p |> tap (Thm.join_proofs o single)
+    in
+      if (Thm.cprop_of thm) aconvc ct then ()
+      else
+        z3_exn (Pretty.string_of (Pretty.big_list
+          ("proof step failed: " ^ quote (Old_Z3_Proof_Parser.string_of_rule r) ^
+            " (#" ^ string_of_int idx ^ ")")
+          (pretty_goal ctxt (map (thm_of o fst) ps) (Thm.prop_of thm) @
+            [Pretty.block [Pretty.str "expected: ",
+              Syntax.pretty_term ctxt (Thm.term_of ct)]])))
+    end
+
+
+(** overall reconstruction procedure **)
+
+local
+  fun not_supported r = raise Fail ("Z3: proof rule not implemented: " ^
+    quote (Old_Z3_Proof_Parser.string_of_rule r))
+
+  fun prove_step simpset vars r ps ct (cxp as (cx, ptab)) =
+    (case (r, ps) of
+      (* core rules *)
+      (Old_Z3_Proof_Parser.True_Axiom, _) => (Thm Old_Z3_Proof_Literals.true_thm, cxp)
+    | (Old_Z3_Proof_Parser.Asserted, _) => raise Fail "bad assertion"
+    | (Old_Z3_Proof_Parser.Goal, _) => raise Fail "bad assertion"
+    | (Old_Z3_Proof_Parser.Modus_Ponens, [(p, _), (q, _)]) =>
+        (mp q (thm_of p), cxp)
+    | (Old_Z3_Proof_Parser.Modus_Ponens_Oeq, [(p, _), (q, _)]) =>
+        (mp q (thm_of p), cxp)
+    | (Old_Z3_Proof_Parser.And_Elim, [(p, i)]) =>
+        and_elim (p, i) ct ptab ||> pair cx
+    | (Old_Z3_Proof_Parser.Not_Or_Elim, [(p, i)]) =>
+        not_or_elim (p, i) ct ptab ||> pair cx
+    | (Old_Z3_Proof_Parser.Hypothesis, _) => (Thm (Thm.assume ct), cxp)
+    | (Old_Z3_Proof_Parser.Lemma, [(p, _)]) => (lemma (thm_of p) ct, cxp)
+    | (Old_Z3_Proof_Parser.Unit_Resolution, (p, _) :: ps) =>
+        (unit_resolution (thm_of p) (map (thm_of o fst) ps) ct, cxp)
+    | (Old_Z3_Proof_Parser.Iff_True, [(p, _)]) => (iff_true (thm_of p), cxp)
+    | (Old_Z3_Proof_Parser.Iff_False, [(p, _)]) => (iff_false (thm_of p), cxp)
+    | (Old_Z3_Proof_Parser.Distributivity, _) => (distributivity cx ct, cxp)
+    | (Old_Z3_Proof_Parser.Def_Axiom, _) => (def_axiom cx ct, cxp)
+    | (Old_Z3_Proof_Parser.Intro_Def, _) => intro_def ct cx ||> rpair ptab
+    | (Old_Z3_Proof_Parser.Apply_Def, [(p, _)]) => (apply_def (thm_of p), cxp)
+    | (Old_Z3_Proof_Parser.Iff_Oeq, [(p, _)]) => (p, cxp)
+    | (Old_Z3_Proof_Parser.Nnf_Pos, _) => (nnf cx vars (map fst ps) ct, cxp)
+    | (Old_Z3_Proof_Parser.Nnf_Neg, _) => (nnf cx vars (map fst ps) ct, cxp)
+
+      (* equality rules *)
+    | (Old_Z3_Proof_Parser.Reflexivity, _) => (refl ct, cxp)
+    | (Old_Z3_Proof_Parser.Symmetry, [(p, _)]) => (symm p, cxp)
+    | (Old_Z3_Proof_Parser.Transitivity, [(p, _), (q, _)]) => (trans p q, cxp)
+    | (Old_Z3_Proof_Parser.Monotonicity, _) => (monotonicity (map fst ps) ct, cxp)
+    | (Old_Z3_Proof_Parser.Commutativity, _) => (commutativity ct, cxp)
+
+      (* quantifier rules *)
+    | (Old_Z3_Proof_Parser.Quant_Intro, [(p, _)]) => (quant_intro cx vars p ct, cxp)
+    | (Old_Z3_Proof_Parser.Pull_Quant, _) => (pull_quant cx ct, cxp)
+    | (Old_Z3_Proof_Parser.Push_Quant, _) => (push_quant cx ct, cxp)
+    | (Old_Z3_Proof_Parser.Elim_Unused_Vars, _) => (elim_unused_vars cx ct, cxp)
+    | (Old_Z3_Proof_Parser.Dest_Eq_Res, _) => (dest_eq_res cx ct, cxp)
+    | (Old_Z3_Proof_Parser.Quant_Inst, _) => (quant_inst cx ct, cxp)
+    | (Old_Z3_Proof_Parser.Skolemize, _) => skolemize vars ct cx ||> rpair ptab
+
+      (* theory rules *)
+    | (Old_Z3_Proof_Parser.Th_Lemma _, _) =>  (* FIXME: use arguments *)
+        (th_lemma cx simpset (map (thm_of o fst) ps) ct, cxp)
+    | (Old_Z3_Proof_Parser.Rewrite, _) => rewrite simpset [] ct cx ||> rpair ptab
+    | (Old_Z3_Proof_Parser.Rewrite_Star, ps) =>
+        rewrite simpset (map fst ps) ct cx ||> rpair ptab
+
+    | (Old_Z3_Proof_Parser.Nnf_Star, _) => not_supported r
+    | (Old_Z3_Proof_Parser.Cnf_Star, _) => not_supported r
+    | (Old_Z3_Proof_Parser.Transitivity_Star, _) => not_supported r
+    | (Old_Z3_Proof_Parser.Pull_Quant_Star, _) => not_supported r
+
+    | _ => raise Fail ("Z3: proof rule " ^
+        quote (Old_Z3_Proof_Parser.string_of_rule r) ^
+        " has an unexpected number of arguments."))
+
+  fun lookup_proof ptab idx =
+    (case Inttab.lookup ptab idx of
+      SOME p => (p, idx)
+    | NONE => z3_exn ("unknown proof id: " ^ quote (string_of_int idx)))
+
+  fun prove simpset vars (idx, step) (_, cxp as (ctxt, ptab)) =
+    let
+      val Old_Z3_Proof_Parser.Proof_Step {rule=r, prems, prop, ...} = step
+      val ps = map (lookup_proof ptab) prems
+      val _ = trace_before ctxt idx r
+      val (thm, (ctxt', ptab')) =
+        cxp
+        |> prove_step simpset vars r ps prop
+        |> tap (check_after idx r ps prop)
+    in (thm, (ctxt', Inttab.update (idx, thm) ptab')) end
+
+  fun make_discharge_rules rules = rules @ [@{thm allI}, @{thm refl},
+    @{thm reflexive}, Old_Z3_Proof_Literals.true_thm]
+
+  fun discharge_assms_tac rules =
+    REPEAT (HEADGOAL (resolve_tac rules ORELSE' SOLVED' discharge_sk_tac))
+    
+  fun discharge_assms ctxt rules thm =
+    if Thm.nprems_of thm = 0 then Goal.norm_result ctxt thm
+    else
+      (case Seq.pull (discharge_assms_tac rules thm) of
+        SOME (thm', _) => Goal.norm_result ctxt thm'
+      | NONE => raise THM ("failed to discharge premise", 1, [thm]))
+
+  fun discharge rules outer_ctxt (p, (inner_ctxt, _)) =
+    thm_of p
+    |> singleton (Proof_Context.export inner_ctxt outer_ctxt)
+    |> discharge_assms outer_ctxt (make_discharge_rules rules)
+in
+
+fun reconstruct outer_ctxt recon output =
+  let
+    val {context=ctxt, typs, terms, rewrite_rules, assms} = recon
+    val (asserted, steps, vars, ctxt1) =
+      Old_Z3_Proof_Parser.parse ctxt typs terms output
+
+    val simpset =
+      Old_Z3_Proof_Tools.make_simpset ctxt1 (Named_Theorems.get ctxt1 @{named_theorems z3_simp})
+
+    val ((is, rules), cxp as (ctxt2, _)) =
+      add_asserted outer_ctxt rewrite_rules assms asserted ctxt1
+  in
+    if Config.get ctxt2 Old_SMT_Config.filter_only_facts then (is, @{thm TrueI})
+    else
+      (Thm @{thm TrueI}, cxp)
+      |> fold (prove simpset vars) steps 
+      |> discharge rules outer_ctxt
+      |> pair []
+  end
+
+end
+
+end