1 (* ====================================================== *)
2 (* Squolem proof reconstruction *)
3 (* (c) Copyright, Ondřej Kunčar 2010-11 *)
4 (* ====================================================== *)
9 let show_progress = ref false;;
10 let show_timing = ref false;;
11 let delete_qbf_tempfiles = ref true;;
13 type quantifier = Existential of term | Universal of term;;
15 let make_variable index =
16 if index <= 0 then failwith "Variable of index 0 or lesser is not allowed"
17 else mk_var ("v_"^(string_of_int index), bool_ty)
20 let make_literal index =
21 if index < 0 then mk_neg (make_variable (-index))
22 else make_variable index
25 let destroy_variable var =
26 let var_string = string_of_term var in
27 int_of_string (String.sub var_string 2 (String.length var_string -2))
30 let destroy_literal lit =
32 true -> - destroy_variable (dest_neg lit)
33 | false -> destroy_variable lit
36 let get_quant_var quantifier =
43 Pervasives.(||) (is_exists tm) (is_forall tm)
47 if is_exists tm then dest_exists tm
51 module type Qbfcontextsig =
53 type variables = (int,unit) Hashtbl.t;;
54 type extensions = (int,term) Hashtbl.t;;
56 type quantifiers = quantifier list;;
57 type aux_variables = int list;;
58 type q_levels = int array;;
60 (** all variables, i.e, variables in a formula and auxiliary variables from extensions *)
62 extensions:extensions;
63 mutable aux_variables:aux_variables;
64 (** quantifiers prefix in bottom-up ordering *)
65 mutable quantifiers:quantifiers;
66 mutable q_levels:q_levels;
67 mutable q_ordered_levels:q_levels };;
69 val create_context : int -> context
70 (** quantifiers must be in bottom-up ordering *)
71 val set_quantifiers : context -> quantifiers -> unit
72 val check_variable : context -> int -> unit
73 val check_fresh_variable : context -> int -> unit
74 val add_universal_variable : context -> int -> unit
75 val add_existential_variable : context -> int -> unit
76 val add_extension : context -> int -> term -> unit
77 val add_conclusion_eq : context -> int -> term -> unit
78 val get_extensions : context -> (term * term) list
79 val get_extension : context -> int -> term
80 val get_quantifiers : context -> quantifiers
81 val get_aux_variables : context -> aux_variables
82 val make_quantifiers_levels : context -> unit
83 val make_ordered_quantifiers_levels : context -> unit
84 val lt_levels : context -> int -> int -> bool
85 val lt_ordered_levels : context -> int -> int -> bool
88 module Qbfcontext : Qbfcontextsig =
90 type variables = (int,unit) Hashtbl.t;;
91 type extensions = (int,term) Hashtbl.t;;
93 type quantifiers = quantifier list;;
94 type aux_variables = int list;;
95 type q_levels = int array;;
98 extensions:extensions;
99 mutable aux_variables:aux_variables;
100 mutable quantifiers:quantifiers;
101 mutable q_levels:q_levels;
102 mutable q_ordered_levels:q_levels
105 let create_context var_count =
106 { variables = Hashtbl.create (2*var_count);
107 extensions = Hashtbl.create var_count;
110 q_levels = Array.make 0 0;
111 q_ordered_levels = Array.make 0 0 }
114 let set_quantifiers context quants =
115 context.quantifiers <- quants
118 let check_variable context var_index =
119 if not (Hashtbl.mem context.variables var_index) then failwith ((string_of_int var_index)^" is undefined variable")
122 let check_fresh_variable context var_index =
123 if Hashtbl.mem context.variables var_index then failwith ((string_of_int var_index)^" is not a fresh variable")
126 let add_universal_variable context var_index =
127 check_fresh_variable context var_index;
128 Hashtbl.add context.variables var_index ()
131 let add_existential_variable context var_index =
132 check_fresh_variable context var_index;
133 Hashtbl.add context.variables var_index ();
134 Hashtbl.add context.extensions var_index `T`
137 let add_aux_variable context var_index =
138 check_fresh_variable context var_index;
139 Hashtbl.add context.variables var_index ();
140 context.aux_variables <- var_index::context.aux_variables
143 let add_aux_quantifier context var_index free_variables =
144 let quantifier = Existential (make_variable var_index) in
145 let rec remove_from_list l ls =
148 | l'::ls' when l'=l -> ls'
149 | l'::ls'-> l'::remove_from_list l ls'
151 let rec insert_quantifier quantifiers free_variables =
152 match free_variables with
153 [] -> quantifier::quantifiers
154 | _ -> match quantifiers with
155 q::qs -> q::(insert_quantifier qs (remove_from_list (get_quant_var q) free_variables))
156 | [] -> failwith "add_aux_quantifier: logic error"
158 context.quantifiers <- List.rev ((insert_quantifier (List.rev context.quantifiers) free_variables))
161 let add_extension context var_index formula =
162 add_aux_variable context var_index;
163 add_aux_quantifier context var_index (variables formula);
164 Hashtbl.add context.extensions var_index formula
167 let add_conclusion_eq context var_index formula =
168 Hashtbl.replace context.extensions var_index formula
171 let get_extension context var_index =
172 Hashtbl.find context.extensions var_index
175 let get_extensions context =
176 Hashtbl.fold (fun f s l -> (make_variable f,s)::l) context.extensions []
179 let get_quantifiers context =
183 let get_aux_variables context =
184 context.aux_variables
187 let make_quantifiers_levels_inter context =
188 let quantifiers = context.quantifiers in
189 let rec loop arr quants level =
193 arr.(((destroy_variable o get_quant_var) q) - 1) <- level;
194 loop arr qs (level - 1)
196 let arr = Array.make (List.length quantifiers) 0 in
197 let arr' = loop arr quantifiers (List.length quantifiers) in
201 let make_quantifiers_levels context =
202 context.q_levels <- make_quantifiers_levels_inter context
205 let make_ordered_quantifiers_levels context =
206 context.q_ordered_levels <- make_quantifiers_levels_inter context
209 let lt_levels context v1 v2 =
210 context.q_levels.(v1-1) < context.q_levels.(v2-1)
213 let lt_ordered_levels context v1 v2 =
214 context.q_ordered_levels.(v1-1) < context.q_ordered_levels.(v2-1)
221 let rec strip_quantifiers tm =
223 let (var,tm') = dest_forall tm in
224 let (q',body) = (strip_quantifiers tm') in
225 ((Universal var)::q',body)
226 else if is_exists tm then
227 let (var,tm') = dest_exists tm in
228 let (q',body) = (strip_quantifiers tm') in
229 ((Existential var)::q',body)
233 (** strip quantifiers in bottom-up ordering *)
234 let strip_quantifiers_r tm =
235 let rec loop tm acc =
237 let (var,tm') = dest_forall tm in
238 loop tm' ((Universal var)::acc)
239 else if is_exists tm then
240 let (var,tm') = dest_exists tm in
241 loop tm' ((Existential var)::acc)
246 (** strip quantifiers in bottom-up ordering *)
247 let strip_quantifiers_rx tm =
248 let rec loop tm acc =
250 let (var,tm') = dest_forall tm in
251 loop tm' ((true, var)::acc)
252 else if is_exists tm then
253 let (var,tm') = dest_exists tm in
254 loop tm' ((false, var)::acc)
259 let quantifiers_fold_left exist_fn universal_fn thm quantifiers =
260 let quant_fn thm quantifier =
261 match quantifier with
262 Universal var -> universal_fn var thm
263 | Existential var -> exist_fn var thm
265 List.fold_left quant_fn thm quantifiers
268 let is_negated lit_ind = lit_ind < 0;;
270 let read_index token_stream =
271 let index_token = Stream.next token_stream in
272 match index_token with
273 Genlex.Int index -> index
274 | _ -> failwith "Bad index of variable"
279 let read_extension_ite context new_var_index token_stream =
280 let x_v_i = read_index token_stream in
281 let y_v_i = read_index token_stream in
282 let z_v_i = read_index token_stream in
283 check_variable context (var x_v_i);
284 check_variable context (var y_v_i);
285 check_variable context (var z_v_i);
286 let x_v = make_literal x_v_i in
287 let y_v = make_literal y_v_i in
288 let z_v = make_literal z_v_i in
289 let formula = mk_disj (mk_conj (x_v,y_v),mk_conj(mk_neg x_v,z_v)) in
290 add_extension context new_var_index formula;
293 let read_extension_and context new_var_index token_stream =
294 let rec read_conjucts context token_stream =
295 let lit_ind = read_index token_stream in
296 if lit_ind = 0 then []
299 check_variable context (var lit_ind);
300 (make_literal lit_ind)::(read_conjucts context token_stream)
303 let conjucts = read_conjucts context token_stream in
304 let conjucts' = match conjucts with
306 | _ -> list_mk_conj conjucts
308 add_extension context new_var_index conjucts';
311 let read_extension_line context token_stream =
312 let new_var_index = read_index token_stream in
313 let extension_type = Stream.next token_stream in
314 match extension_type with
315 Genlex.Kwd "I" -> read_extension_ite context new_var_index token_stream
316 | Genlex.Kwd "A" -> read_extension_and context new_var_index token_stream
317 | _ -> failwith "Unknown type of extension line"
320 let read_header context token_stream =
321 match Stream.next token_stream with
322 Genlex.Kwd "QBCertificate" -> ()
323 | _ -> failwith "Missing header"
326 let read_resolution_line context token_stream =
327 failwith "Resolution line: not yet implemented!";
331 let rec read_equalities context token_stream =
333 let exist_var_i = read_index token_stream in
334 check_variable context exist_var_i;
335 let extension_var_i = read_index token_stream in
336 check_variable context (var extension_var_i);
337 let extension_var = make_literal extension_var_i in
338 add_conclusion_eq context exist_var_i extension_var;
339 read_equalities context token_stream
340 with Stream.Failure -> ()
343 let read_conlude_line context token_stream =
344 match Stream.next token_stream with
345 Genlex.Kwd "VALID" -> read_equalities context token_stream
346 | Genlex.Kwd "INVALID" -> failwith "INVALID formula: not yet implemted!"
347 | _ -> failwith "Unknown type of conclusion"
350 let read_certificate context token_stream =
351 read_header context token_stream;
352 let rec read_line context token_stream =
353 match Stream.next token_stream with
354 Genlex.Kwd "E" -> read_extension_line context token_stream; read_line context token_stream
355 | Genlex.Kwd "R" -> read_resolution_line context token_stream; read_line context token_stream
356 | Genlex.Kwd "CONCLUDE" -> read_conlude_line context token_stream
357 | _ -> failwith "Unknown type of line"
359 read_line context token_stream
362 let PROPAGATE_FORALL =
363 let MONO_FORALL_B = (UNDISCH o prove)
364 (`(!x:bool. A x ==> B x) ==> (!) A ==> (!) B`,
366 GEN_REWRITE_TAC (BINOP_CONV o RAND_CONV) [GSYM ETA_AX] THEN
368 let a_tm = rand(lhand(concl MONO_FORALL_B))
369 and b_tm = rand(rand(concl MONO_FORALL_B))
370 and h_tm = hd(hyp MONO_FORALL_B) in
372 let ath = GEN_ALPHA_CONV v1 h_tm in
373 let atm = rand(concl ath) in
374 let pth = PROVE_HYP (EQ_MP (SYM ath) (ASSUME atm)) MONO_FORALL_B in
376 let tm = concl thm in
377 let ip,q = dest_comb tm in
378 let i,p = dest_comb ip in
379 let pabs = mk_abs(v1,p)
380 and qabs = mk_abs(v1,q) in
381 let th1 = AP_TERM i (BETA(mk_comb(pabs,v1))) in
382 let th2 = MK_COMB(th1,BETA(mk_comb(qabs,v1))) in
383 let th3 = GEN v1 (EQ_MP (SYM th2) thm) in
384 let th4 = INST [pabs,a_tm; qabs,b_tm] pth in
387 let PROPAGATE_RIGHT =
388 let MONO_EXISTS_RIGHT_B = (UNDISCH o prove)
389 (`(A ==> B(x:bool)) ==> A ==> (?) B`,
390 ASM_CASES_TAC `A:bool` THEN ASM_REWRITE_TAC[] THEN
391 GEN_REWRITE_TAC (RAND_CONV o RAND_CONV) [GSYM ETA_AX] THEN
393 let a_tm = lhand(concl MONO_EXISTS_RIGHT_B)
394 and b_tm = rand(rand(concl MONO_EXISTS_RIGHT_B))
395 and h_tm = hd(hyp MONO_EXISTS_RIGHT_B) in
396 let x_tm = rand(rand h_tm) in
398 let tm = concl thm in
399 let ip,q = dest_comb tm in
400 let qabs = mk_abs(v,q) in
401 let th1 = AP_TERM ip (BETA(mk_comb(qabs,v))) in
402 let th2 = EQ_MP (SYM th1) thm in
403 let th3 = INST [rand ip,a_tm; qabs,b_tm; v,x_tm] MONO_EXISTS_RIGHT_B in
407 let MONO_EXISTS_LEFT_B = (UNDISCH o prove)
408 (`(!x:bool. A x ==> B) ==> (?) A ==> B`,
409 ASM_CASES_TAC `B:bool` THEN ASM_REWRITE_TAC[] THEN
410 GEN_REWRITE_TAC (funpow 3 RAND_CONV) [GSYM ETA_AX] THEN
412 let a_tm = rand(lhand(concl MONO_EXISTS_LEFT_B))
413 and b_tm = rand(concl MONO_EXISTS_LEFT_B)
414 and h_tm = hd(hyp MONO_EXISTS_LEFT_B) in
416 let ath = GEN_ALPHA_CONV v h_tm in
417 let atm = rand(concl ath) in
418 let pth = PROVE_HYP (EQ_MP (SYM ath) (ASSUME atm)) MONO_EXISTS_LEFT_B in
420 let tm = concl thm in
421 let ip,q = dest_comb tm in
422 let i,p = dest_comb ip in
423 let pabs = mk_abs(v,p) in
424 let th1 = AP_THM (AP_TERM i (BETA(mk_comb(pabs,v)))) q in
425 let th2 = GEN v (EQ_MP (SYM th1) thm) in
426 let th3 = INST [pabs,a_tm; q,b_tm] pth in
429 let PROPAGATE_QUANTIFIERS_R thm ext_quants quants =
430 let rec propagate_both thm ext_quants quants =
431 match (ext_quants,quants) with
432 | ((Universal v1)::ext_quantss,(Universal v2)::quantss) ->
433 propagate_both (PROPAGATE_FORALL v1 thm) ext_quantss quantss
434 | (_,_) -> (thm,ext_quants,quants)
436 let rec propagate_right thm quants =
438 | (Existential v)::quantss ->
439 propagate_right (PROPAGATE_RIGHT v thm) quantss
442 let rec propagate_left thm ext_quants =
443 match ext_quants with
444 | (Existential v)::ext_quantss ->
445 propagate_left (PROPAGATE_LEFT v thm) ext_quantss
446 | _ -> (thm,ext_quants)
448 let rec propagate thm ext_quants quants =
449 match (ext_quants,quants) with
451 | (_,((Existential _)::_)) ->
452 let (thm',quants') = propagate_right thm quants in
453 let (thm'',ext_quants') = propagate_left thm' ext_quants in
454 propagate thm'' ext_quants' quants'
455 | (((Existential _)::_),_) ->
456 let (thm',ext_quants') = propagate_left thm ext_quants in
457 propagate thm' ext_quants' quants
458 | ((Universal _)::_,(Universal _)::_) ->
459 let (thm',ext_quants',quants') = propagate_both thm ext_quants quants in
460 propagate thm' ext_quants' quants'
461 | _ -> failwith "PROPAGATE_QUANTIFIERS_R: logic error"
463 propagate thm ext_quants quants
466 let order_quantifiers context =
467 let add_var vertices graph var_index =
468 Gr.add_vertex graph (make_vertex var_index);
469 let extension_vars = variables (get_extension context var_index) in
470 let add_ext_var ext_var =
471 let ext_var_index = destroy_variable ext_var in
472 if Hashtbl.mem vertices ext_var_index then
473 Gr.add_edge graph (make_vertex ext_var_index) (make_vertex var_index)
475 List.iter add_ext_var extension_vars
477 let rec is_sorted var_index_list =
478 let is_sorted_var var_index =
479 let extension_vars = variables (get_extension context var_index) in
480 List.fold_left (fun ret var -> ret && lt_levels context (destroy_variable var) var_index) true extension_vars
482 match var_index_list with
484 | var::vars -> if is_sorted_var var then is_sorted vars
487 (** exists is in up-bottom ordering *)
488 let rec order_exists quantifiers exists =
489 let order_exists' tail =
490 if is_sorted exists then
491 List.fold_left (fun tail var_index -> (Existential (make_variable var_index))::tail) tail exists
493 let graph = Gr.create () in
494 let vertices = Hashtbl.create (List.length exists) in
495 List.iter (fun var -> Hashtbl.add vertices var ()) exists;
496 List.iter (fun var -> add_var vertices graph var) exists;
497 Topo.fold (fun vertex tail -> (Existential (make_variable (dest_vertex vertex)))::tail) graph tail
499 match quantifiers with
500 [] -> order_exists' []
501 | (Universal v)::qs -> order_exists' ((Universal v)::order qs)
502 | (Existential v)::qs ->
503 order_exists qs ((destroy_variable v)::exists)
506 match quantifiers with
508 | (Universal v)::qs -> (Universal v)::order qs
509 | (Existential v)::qs ->
510 order_exists ((Existential v)::qs) []
512 set_quantifiers context (order (get_quantifiers context));
513 make_ordered_quantifiers_levels context
516 let match_time = ref 0.0;;
517 let lift_time = ref 0.0;;
518 let gen_time = ref 0.0;;
519 let test_time = ref 0.0;;
522 let timex label f x =
523 if not (!show_timing) then f x else
524 let start_time = Sys.time() in
525 try let result = f x in
526 let finish_time = Sys.time() in
527 report("CPU time (user): "^(string_of_float(finish_time -. start_time))^" ("^label^")");
530 let finish_time = Sys.time() in
531 Format.print_string("Failed after (user) CPU time of "^
532 (string_of_float(finish_time -. start_time))^" ("^label^")"^": ");
535 let my_time f x time_var =
536 if not (!show_timing) then f x else
537 let start_time = Sys.time() in
538 try let result = f x in
539 let finish_time = Sys.time() in
540 time_var := !time_var +. (finish_time -. start_time);
543 let finish_time = Sys.time() in
544 time_var := !time_var +. (finish_time -. start_time);
547 let report_time label time_var =
549 report("CPU time (user): "^(string_of_float(!time_var))^" ("^label^")");
552 let FORALL_SIMP2 = prove
556 let ADD_MISSING_UNIVERSALS th quants =
557 let rec add_u quants tm =
562 | Existential _ -> BINDER_CONV (add_u qs) tm
564 if Pervasives.(||) (not (has_quant tm)) (Pervasives.compare ((fst o dest_quant) tm) v != 0) then
565 let renamed_rewr = EQ_MP (ONCE_DEPTH_CONV (ALPHA_CONV v) (concl FORALL_SIMP2)) FORALL_SIMP2 in
566 (PURE_ONCE_REWRITE_CONV [renamed_rewr] THENC BINDER_CONV (add_u qs)) tm
568 BINDER_CONV (add_u qs) tm
570 EQ_MP (add_u (rev quants) (concl th)) th
573 let AX_UXU = (UNDISCH o prove)
574 (`(!x:bool. p x /\ q ==> r x) ==> (!) p /\ q ==> (!) r`,
575 let AX_UXU = MESON [] `(!x:bool. ((A x /\ B)==>C x))==>(((!x:bool. A x) /\ B)==> !x:bool. C x)` in
576 DISCH_THEN(MP_TAC o MATCH_MP AX_UXU) THEN REWRITE_TAC[ETA_AX])
577 and AX_EXE = (UNDISCH o prove)
578 (`(!x:bool. p x /\ q ==> r x) ==> (?) p /\ q ==> (?) r`,
579 let AX_EXE = MESON [] `(!x:bool. ((A x /\ B)==>C x))==>(((?x:bool. A x) /\ B)==> ?x:bool. C x)` in
580 DISCH_THEN(MP_TAC o MATCH_MP AX_EXE) THEN REWRITE_TAC[ETA_AX]);;
583 let p_tm = rand(lhand(lhand(concl ax)))
584 and q_tm = rand(lhand(concl ax))
585 and r_tm = rand(rand(concl ax))
586 and h_tm = hd(hyp ax) in
588 let ath = GEN_ALPHA_CONV var h_tm in
589 let atm = rand(concl ath) in
590 let ax' = PROVE_HYP (EQ_MP (SYM ath) (ASSUME atm)) ax in
593 let ipq,r = dest_comb tm in
594 let i,pq = dest_comb ipq in
595 let ap,q = dest_comb pq in
596 let a,p = dest_comb ap in
597 let pabs = mk_abs(var,p)
598 and rabs = mk_abs(var,r) in
599 let th1 = AP_THM (AP_TERM a (BETA(mk_comb(pabs,var)))) q in
600 let th2 = MK_COMB(AP_TERM i th1,BETA(mk_comb(rabs,var))) in
601 let th3 = GEN var (EQ_MP (SYM th2) th) in
602 let th4 = INST [pabs,p_tm; q,q_tm; rabs,r_tm] ax' in
605 let AX_XUU = (UNDISCH o prove)
606 (`(!x:bool. p /\ q x ==> r x) ==> p /\ (!) q ==> (!) r`,
607 let AX_XUU = MESON [] `(!x:bool. ((A /\ B x)==>C x))==>((A /\ !x:bool. B x)==> !x:bool. C x)` in
608 DISCH_THEN(MP_TAC o MATCH_MP AX_XUU) THEN REWRITE_TAC[ETA_AX])
609 and AX_XEE = (UNDISCH o prove)
610 (`(!x:bool. p /\ q x ==> r x) ==> p /\ (?) q ==> (?) r`,
611 let AX_XEE = MESON [] `(!x:bool. ((A /\ B x)==>C x))==>((A /\ ?x:bool. B x)==> ?x:bool. C x)` in
612 DISCH_THEN(MP_TAC o MATCH_MP AX_XEE) THEN REWRITE_TAC[ETA_AX]);;
615 let p_tm = lhand(lhand(concl ax))
616 and q_tm = rand(rand(lhand(concl ax)))
617 and r_tm = rand(rand(concl ax))
618 and h_tm = hd(hyp ax) in
620 let ath = GEN_ALPHA_CONV var h_tm in
621 let atm = rand(concl ath) in
622 let ax' = PROVE_HYP (EQ_MP (SYM ath) (ASSUME atm)) ax in
625 let ipq,r = dest_comb tm in
626 let i,pq = dest_comb ipq in
627 let ap,q = dest_comb pq in
628 let a,p = dest_comb ap in
629 let qabs = mk_abs(var,q)
630 and rabs = mk_abs(var,r) in
631 let th1 = AP_TERM ap (BETA(mk_comb(qabs,var))) in
632 let th2 = MK_COMB(AP_TERM i th1,BETA(mk_comb(rabs,var))) in
633 let th3 = GEN var (EQ_MP (SYM th2) th) in
634 let th4 = INST [p,p_tm; qabs,q_tm; rabs,r_tm] ax' in
637 let AX_UUU = (UNDISCH o prove)
638 (`(!x:bool. p x /\ q x ==> r x) ==> (!) p /\ (!) q ==> (!) r`,
639 let AX_UUU = MESON [] `(!x:bool. ((A x /\ B x)==>C x))==>(((!x:bool. A x) /\ !x:bool. B x)==> !x:bool. C x)` in
640 DISCH_THEN(MP_TAC o MATCH_MP AX_UUU) THEN REWRITE_TAC[ETA_AX])
641 and AX_EUE = (UNDISCH o prove)
642 (`(!x:bool. p x /\ q x ==> r x) ==> (?) p /\ (!) q ==> (?) r`,
643 let AX_EUE = MESON [] `(!x:bool. ((A x /\ B x)==>C x))==>(((?x:bool. A x) /\ !x:bool. B x)==> ?x:bool. C x)` in
644 DISCH_THEN(MP_TAC o MATCH_MP AX_EUE) THEN REWRITE_TAC[ETA_AX])
645 and AX_UEE = (UNDISCH o prove)
646 (`(!x:bool. p x /\ q x ==> r x) ==> (!) p /\ (?) q ==> (?) r`,
647 let AX_UEE = MESON [] `(!x:bool. ((A x /\ B x)==>C x))==>(((!x:bool. A x) /\ ?x:bool. B x)==> ?x:bool. C x)` in
648 DISCH_THEN(MP_TAC o MATCH_MP AX_UEE) THEN REWRITE_TAC[ETA_AX]);;
651 let p_tm = rand(lhand(lhand(concl ax)))
652 and q_tm = rand(rand(lhand(concl ax)))
653 and r_tm = rand(rand(concl ax))
654 and h_tm = hd(hyp ax) in
656 let ath = GEN_ALPHA_CONV var h_tm in
657 let atm = rand(concl ath) in
658 let ax' = PROVE_HYP (EQ_MP (SYM ath) (ASSUME atm)) ax in
661 let ipq,r = dest_comb tm in
662 let i,pq = dest_comb ipq in
663 let ap,q = dest_comb pq in
664 let a,p = dest_comb ap in
665 let pabs = mk_abs(var,p)
666 and qabs = mk_abs(var,q)
667 and rabs = mk_abs(var,r) in
668 let th0 = AP_TERM a (BETA(mk_comb(pabs,var))) in
669 let th1 = MK_COMB(th0,BETA(mk_comb(qabs,var))) in
670 let th2 = MK_COMB(AP_TERM i th1,BETA(mk_comb(rabs,var))) in
671 let th3 = GEN var (EQ_MP (SYM th2) th) in
672 let th4 = INST [pabs,p_tm; qabs,q_tm; rabs,r_tm] ax' in
675 let solve_quantifiers context conjuction =
676 let solve_right_quantifier thm quant2 =
678 | Universal v2 -> LIFT_RIGHT AX_XUU v2 thm
679 | Existential v2 -> LIFT_RIGHT AX_XEE v2 thm
681 let solve_left_quantifier thm quant1 =
683 | Universal v1 -> LIFT_LEFT AX_UXU v1 thm
684 | Existential v1 -> LIFT_LEFT AX_EXE v1 thm
686 let solve_both_quantifiers thm quant1 quant2 =
687 match (quant1,quant2) with
688 (Universal v1, Universal v2) -> LIFT_BOTH AX_UUU v1 thm
689 | (Existential v1, Universal v2) -> LIFT_BOTH AX_EUE v1 thm
690 | (Universal v1, Existential v2) -> LIFT_BOTH AX_UEE v1 thm
691 | _ -> failwith "Logic error in solve_quantifier"
693 let rec loop thm quants1 quants2 =
694 match (quants1,quants2) with
696 | (qs1,[]) -> List.fold_left solve_left_quantifier thm qs1
697 | ([],qs2) -> List.fold_left solve_right_quantifier thm qs2
698 | (quant1::qs1,quant2::qs2) ->
699 let quant_var1 = get_quant_var quant1 in
700 let quant_var2 = get_quant_var quant2 in
701 if quant_var1 = quant_var2 then
702 let thm' = solve_both_quantifiers thm quant1 quant2 in
705 if lt_ordered_levels context (destroy_variable quant_var1) (destroy_variable quant_var2) then
706 let thm' = solve_right_quantifier thm quant2 in
707 loop thm' (quant1::qs1) qs2
709 let thm' = solve_left_quantifier thm quant1 in
710 loop thm' qs1 (quant2::qs2)
712 let conclusion = concl conjuction in
713 let (conj1,conj2) = dest_conj conclusion in
714 let (quants1,body1) = strip_quantifiers_r conj1 in
715 let (quants2,body2) = strip_quantifiers_r conj2 in
717 let rew_thm = loop (DISCH_ALL (ASSUME (mk_conj (body1,body2)))) quants1 quants2 in
720 print_thm conjuction;
722 my_time (MP rew_thm) conjuction match_time
725 let make_quantified_model_equality =
726 let pth = MESON[] `?x:bool. x = t` in
727 let t_tm = rand(body(rand(concl pth))) in
728 fun quantifier_data (exist_var,right_side) ->
729 let free_vars = frees right_side in
730 let n = quantifier_data exist_var in
731 let quants = sort (decreasing quantifier_data)
732 (filter (fun v -> quantifier_data v > n) free_vars) in
733 let exist_eq_thm = INST[right_side,t_tm] (CONV_RULE(GEN_ALPHA_CONV exist_var) pth) in
734 let ret = GENL quants exist_eq_thm in
740 let construct_model context equalities =
741 match equalities with
743 | (eq::eqs) -> List.fold_left (C (curry mk_conj)) eq eqs
746 let construct_model_thm context equalities =
747 let eq_length = List.length equalities in
748 let progress = ref 1 in
749 let print_progress () =
750 print_endline ((string_of_int o int_of_float) (((float_of_int !progress)/.(float_of_int eq_length))*.100.0))
752 let construct model eq =
754 let ret = solve_quantifiers context (CONJ eq model) in
756 if !show_progress then
758 progress := !progress + 1;
763 let rec construct_recursively eqs =
765 [] -> failwith "Sanity check failure"
767 | [e1;e2] -> construct e1 e2
768 | _ -> let n = length eqs in
769 let eqs1,eqs2 = chop_list (length eqs / 2) eqs in
770 construct (construct_recursively eqs1) (construct_recursively eqs2)
772 if equalities = [] then quantifiers_fold_left SIMPLE_EXISTS GEN TRUTH (get_quantifiers context)
773 else PURE_REWRITE_RULE[GSYM CONJ_ASSOC] (construct_recursively equalities);;
775 let make_model context =
776 let model_equalities = get_extensions context in
777 let model = construct_model context (List.map mk_eq model_equalities) in
778 let quantifier_list = map (function Universal v -> v | Existential v -> v)
779 (get_quantifiers context) in
780 let quantifier_table = itlist2 (|->) quantifier_list (1--length quantifier_list) undefined in
781 let quantifier_data = apply quantifier_table in
782 let quantified_equalities = timex "make_quantified_equalities" (List.map (make_quantified_model_equality quantifier_data)) model_equalities in
788 print_endline ("Number of extensions: "^ (string_of_int (List.length model_equalities)));
789 let ret = timex "construct_model_thm" (construct_model_thm context) quantified_equalities in
790 report_time "lift" lift_time;
791 report_time "match" match_time;
792 report_time "gen" gen_time;
793 report_time "test" test_time;
796 (*let model_thm = construct_model_thm context (List.map (make_quantified_model_equality context) model_equalities) in*)
800 let check_and_preprocess context formula =
801 match frees formula with
802 [ _ ] -> failwith "Formula has free variables"
804 let nnf_thm = NNF_CONV formula in
805 let prenex_thm = TRANS nnf_thm (PRENEX_CONV (rhs (concl nnf_thm))) in
806 let cnf_thm = TRANS prenex_thm (CNF_CONV (rhs (concl prenex_thm))) in
808 let rec check_and_made_rename formula index rename =
809 let rename_quantifier constr destr add_fresh_variable =
810 let (var,destr_formula) = destr formula in
811 if type_of var <> bool_ty then failwith ((string_of_term var)^" is not of bool type");
812 add_fresh_variable context index;
813 let formula2 = check_and_made_rename destr_formula (index+1) ((make_variable index,var)::rename) in
814 constr (make_variable index,formula2)
816 if is_forall formula then rename_quantifier mk_forall dest_forall add_universal_variable
817 else if is_exists formula then rename_quantifier mk_exists dest_exists add_existential_variable
819 vsubst rename formula
821 let prenex_formula = rhs (concl cnf_thm) in
822 let ret = TRANS cnf_thm (ALPHA prenex_formula (check_and_made_rename prenex_formula 1 [])) in
823 let (quantifiers',_) = strip_quantifiers_r (rhs (concl ret)) in
824 set_quantifiers context quantifiers';
828 let get_temp_file () =
829 Filename.open_temp_file "qbf" ""
832 let split_disjuncts body =
834 (fun c d -> (disjuncts c) :: d)
838 let string_of_literal lit =
839 string_of_int (destroy_literal lit);
842 type prefix = Exists of term list | Forall of term list;;
844 let rec strip_quantifiers_as_prefix formula =
845 if is_forall formula then
846 let (quants,formula') = strip_forall formula in
847 let (quants',body) = strip_quantifiers_as_prefix formula' in
848 ((Forall quants)::quants',body)
849 else if is_exists formula then
850 let (quants,formula') = strip_exists formula in
851 let (quants',body) = strip_quantifiers_as_prefix formula' in
852 ((Exists quants)::quants',body)
857 let make_input context formula var_count =
858 let (file_name,file_stream) = get_temp_file () in
860 let (quantifiers_list, body) = strip_quantifiers_as_prefix formula in
861 let clause_count = length(conjuncts body) in
864 let disjuncts_list = split_disjuncts body in
866 let out s = output_string file_stream s in
867 let formula_string = Str.global_replace (Str.regexp_string "\n") "\nc " (string_of_term formula) in
868 out "c "; out formula_string;out "\n";
871 out (string_of_int var_count); out " ";
872 out (string_of_int clause_count); out "\n";
874 let print_quantifiers q =
876 List.iter (fun var -> (out(string_of_literal var); out " ")) q;
880 Exists vars -> out "e "; print_vars vars
881 | Forall vars -> out "a "; print_vars vars
885 (fun q -> print_quantifiers q)
889 (fun l -> (List.iter (fun lit ->
890 (out(string_of_literal lit); out " ")) l;
893 close_out file_stream;
896 close_out file_stream;
900 let execute_squolem input_file_name =
901 let exec_name = "squolem2 -c " ^ input_file_name in
902 let _ = Sys.command exec_name in
903 input_file_name ^ ".qbc"
906 let parse_certificate context certificate_file_name =
907 let file_channel = Pervasives.open_in certificate_file_name in
908 let token_stream = (Genlex.make_lexer ["I";"A";"QBCertificate";"VALID";"INVALID";"E";"R";"CONCLUDE"] (Stream.of_channel file_channel)) in
909 read_certificate context token_stream
911 let print_model context =
912 let (model, model_thm) = make_model context in
913 print_endline (string_of_term model);
914 print_endline (string_of_thm model_thm)
917 let print_quantifiers context =
918 let print_quantifier quant =
920 Existential v -> print_string "E "; print_term v; print_string " "
921 | Universal v -> print_string "F "; print_term v; print_string " "
923 List.iter print_quantifier (get_quantifiers context);
928 let ASSOC_EQ_CONV th =
929 let assoc_canon = ASSOC_CONV th in
930 fun tm -> let l,r = dest_eq tm in
931 TRANS (assoc_canon l) (SYM(assoc_canon r)) in
932 let opacs = [`\/`,ASSOC_EQ_CONV DISJ_ASSOC;
933 `/\`,ASSOC_EQ_CONV CONJ_ASSOC;
934 `<=>`,ASSOC_EQ_CONV(TAUT `(t1 <=> t2 <=> t3) <=> ((t1 <=> t2) <=> t3)`)] in
935 let rec ASSOC_BALANCE_CONV tm =
937 Comb(Comb(op,l),r) when can (assoc op) opacs ->
938 let tms = striplist (dest_binop op) tm in
939 let n = length tms in
940 if n <= 1 then failwith "sanity check failure" else
941 if n = 2 then BINOP_CONV ASSOC_BALANCE_CONV tm else
942 let tms1,tms2 = chop_list (n / 2) tms in
943 let tm1 = list_mk_binop op tms1
944 and tm2 = list_mk_binop op tms2 in
945 let th = assoc op opacs (mk_eq(tm,mk_binop op tm1 tm2)) in
946 CONV_RULE (RAND_CONV (BINOP_CONV ASSOC_BALANCE_CONV)) th
948 let conv = DEPTH_BINOP_CONV `(/\)` (NNFC_CONV THENC CNF_CONV) in
949 fun tm -> let th = COMB2_CONV (RAND_CONV conv) ASSOC_BALANCE_CONV tm in
950 let tm' = rand(concl th) in
951 EQ_MP (SYM th) (ZSAT_PROVE tm');;
953 let build_proof context prenex_thm =
954 let formula = rhs (concl prenex_thm) in
955 let (quants,formula_body) = strip_quantifiers_r formula in
956 timex "make_q_levels" make_quantifiers_levels context;
957 (*print_quantifiers context;*)
958 timex "order_qs" order_quantifiers context;
959 (*print_quantifiers context;*)
960 let (model, model_thm) = timex "make_model" make_model context in
961 let sat_formula = mk_imp (model,formula_body) in
962 let proved_sat_formula = timex "sat" ZSAT_PROVE' sat_formula in
963 let q_propagated_formula = timex "propagate" (PROPAGATE_QUANTIFIERS_R proved_sat_formula (get_quantifiers context)) quants in
964 let (model_quantifiers,_) = strip_quantifiers_r (concl model_thm) in
966 if List.length model_quantifiers != List.length (get_quantifiers context) then
967 MP q_propagated_formula (timex "add_missing" (ADD_MISSING_UNIVERSALS model_thm) (get_quantifiers context))
969 (*MP q_propagated_formula model_thm*)
970 MP q_propagated_formula (timex "add_missing" (ADD_MISSING_UNIVERSALS model_thm) (get_quantifiers context))
972 EQ_MP (GSYM prenex_thm) proved_formula
975 let prove_qbf formula =
976 let var_count = length (variables formula) in
977 let context = create_context var_count in
978 let prenex_thm = timex "prep" (check_and_preprocess context) formula in
979 let input_file_name = timex "make_input" (make_input context (rand (concl prenex_thm))) var_count in
980 let output_file_name = timex "ex_squolem" execute_squolem input_file_name in
981 let _ = timex "parse_cert" (parse_certificate context) output_file_name in
982 let thm = timex "build_proof" (build_proof context) prenex_thm in
983 (if !delete_qbf_tempfiles
984 then (Sys.remove input_file_name; Sys.remove output_file_name)
989 let prove_all_qbf dir =
990 let filter_array f a =
991 let l = Array.to_list a in
992 let ll = List.filter f l in
995 let raw_files = Sys.readdir dir in
996 let files = filter_array (fun name -> Filename.check_suffix name ".qdimacs") raw_files in
997 let run_prover file_name =
998 let name = Filename.chop_suffix file_name ".qdimacs" in
1000 let formula = readQDimacs (dir^"/"^file_name) in
1001 let formula_thm = prove_qbf formula in
1004 Array.map run_prover files