============================== Prover9 ===============================
Prover9 (32) version 2009-02A, February 2009.
Process 11137 was started by mccune on cleo,
Wed Feb 25 09:31:05 2009
The command was "/home/mccune/bin/prover9 -f cancel2.in".
============================== end of head ===========================

============================== INPUT =================================

% Reading from file cancel2.in

assign(max_seconds,30).

formulas(sos).
(x * e) * x = x.
x * (x * y) = y.
(x * y) * (z * u) = (x * z) * (y * u).
((x * x) * x) * x = e.
end_of_list.

formulas(goals).
x * y = z * y -> x = z.
end_of_list.

============================== end of input ==========================

============================== PROCESS NON-CLAUSAL FORMULAS ==========

% Formulas that are not ordinary clauses:
1 x * y = z * y -> x = z # label(non_clause) # label(goal).  [goal].

============================== end of process non-clausal formulas ===

============================== PROCESS INITIAL CLAUSES ===============

% Clauses before input processing:

formulas(usable).
end_of_list.

formulas(sos).
(x * e) * x = x.  [assumption].
x * (x * y) = y.  [assumption].
(x * y) * (z * u) = (x * z) * (y * u).  [assumption].
((x * x) * x) * x = e.  [assumption].
c3 * c2 = c1 * c2.  [deny(1)].
c3 != c1.  [deny(1)].
end_of_list.

formulas(demodulators).
end_of_list.

============================== PREDICATE ELIMINATION =================

No predicates eliminated.

============================== end predicate elimination =============

Auto_denials:  (no changes).

Term ordering decisions:
Predicate symbol precedence:  predicate_order([ = ]).
Function symbol precedence:  function_order([ e, c1, c2, c3, * ]).
After inverse_order:  (no changes).
Unfolding symbols: (none).

Auto_inference settings:
  % set(paramodulation).  % (positive equality literals)

Auto_process settings:  (no changes).

kept:      2 (x * e) * x = x.  [assumption].
kept:      3 x * (x * y) = y.  [assumption].
kept:      4 (x * y) * (z * u) = (x * z) * (y * u).  [assumption].
kept:      5 ((x * x) * x) * x = e.  [assumption].
kept:      6 c3 * c2 = c1 * c2.  [deny(1)].
kept:      7 c3 != c1.  [deny(1)].

============================== end of process initial clauses ========

============================== CLAUSES FOR SEARCH ====================

% Clauses after input processing:

formulas(usable).
end_of_list.

formulas(sos).
2 (x * e) * x = x.  [assumption].
3 x * (x * y) = y.  [assumption].
4 (x * y) * (z * u) = (x * z) * (y * u).  [assumption].
5 ((x * x) * x) * x = e.  [assumption].
6 c3 * c2 = c1 * c2.  [deny(1)].
7 c3 != c1.  [deny(1)].
end_of_list.

formulas(demodulators).
2 (x * e) * x = x.  [assumption].
3 x * (x * y) = y.  [assumption].
5 ((x * x) * x) * x = e.  [assumption].
6 c3 * c2 = c1 * c2.  [deny(1)].
end_of_list.

============================== end of clauses for search =============

============================== SEARCH ================================

% Starting search at 0.01 seconds.

given #1 (I,wt=7): 2 (x * e) * x = x.  [assumption].

given #2 (I,wt=7): 3 x * (x * y) = y.  [assumption].

given #3 (I,wt=15): 4 (x * y) * (z * u) = (x * z) * (y * u).  [assumption].

given #4 (I,wt=9): 5 ((x * x) * x) * x = e.  [assumption].

given #5 (I,wt=7): 6 c3 * c2 = c1 * c2.  [deny(1)].

given #6 (I,wt=3): 7 c3 != c1.  [deny(1)].

given #7 (A,wt=5): 8 e * e = e.  [para(2(a,1),2(a,1,1)),rewrite([3(5)]),flip(a)].

given #8 (T,wt=7): 23 c3 * (c1 * c2) = c2.  [para(6(a,1),3(a,1,2))].

given #9 (T,wt=9): 17 ((x * x) * x) * e = x.  [para(5(a,1),3(a,1,2))].

given #10 (T,wt=13): 9 ((x * y) * x) * (e * y) = x * y.  [para(4(a,1),2(a,1))].

given #11 (T,wt=11): 36 (x * y) * (e * (y * x)) = x.  [para(3(a,1),9(a,1,1,1)),rewrite([3(7)])].

given #12 (A,wt=15): 10 ((x * e) * y) * (x * z) = x * (y * z).  [para(2(a,1),4(a,1,1)),flip(a)].

given #13 (T,wt=9): 50 e * ((x * x) * e) = x.  [para(5(a,1),36(a,1,2,2)),rewrite([44(2),49(4),8(6),44(5)])].

given #14 (T,wt=9): 53 (x * x) * (e * x) = e.  [para(17(a,1),36(a,1,2,2)),rewrite([44(3),3(5)])].

given #15 (T,wt=9): 67 (e * (x * x)) * x = e.  [back_rewrite(5),rewrite([44(2)])].

given #16 (T,wt=9): 79 (x * x) * e = e * x.  [para(50(a,1),3(a,1,2)),flip(a)].

given #17 (A,wt=15): 11 (x * (y * e)) * (z * y) = (x * z) * y.  [para(2(a,1),4(a,1,2)),flip(a)].

given #18 (T,wt=9): 83 (x * e) * (x * x) = e.  [para(53(a,1),4(a,1)),flip(a)].

given #19 (T,wt=9): 123 (x * e) * e = x * x.  [para(83(a,1),3(a,1,2))].

given #20 (T,wt=11): 43 (c2 * c3) * (e * (c1 * c2)) = c2.  [para(23(a,1),9(a,1,1,1)),rewrite([23(14)])].

given #21 (T,wt=11): 44 (x * y) * x = e * (y * x).  [para(36(a,1),3(a,1,2))].

given #22 (A,wt=15): 12 (x * y) * ((x * z) * (y * u)) = z * u.  [para(4(a,1),3(a,1,2))].

given #23 (T,wt=11): 51 (c1 * c2) * (e * (c2 * c3)) = c3.  [para(6(a,1),36(a,1,1))].

given #24 (T,wt=7): 194 (c1 * e) * c3 = c3.  [para(51(a,1),4(a,1)),rewrite([3(9)]),flip(a)].

given #25 (T,wt=11): 85 (e * x) * (x * x) = x * x.  [para(53(a,1),36(a,1,1)),rewrite([3(8)])].

given #26 (T,wt=11): 114 (x * e) * (x * e) = e * x.  [para(11(a,2),79(a,1)),rewrite([8(3)])].

given #27 (A,wt=15): 13 (x * y) * ((x * z) * u) = z * (y * u).  [para(3(a,1),4(a,1,1)),flip(a)].

given #28 (T,wt=7): 359 c3 * (c1 * c1) = c3.  [back_rewrite(201),rewrite([257(9),249(6),3(7)])].

given #29 (T,wt=7): 361 c3 * c3 = c1 * c1.  [para(359(a,1),3(a,1,2))].

============================== PROOF =================================

% Proof 1 at 0.03 (+ 0.00) seconds.
% Length of proof is 26.
% Level of proof is 11.
% Maximum clause weight is 15.
% Given clauses 29.

1 x * y = z * y -> x = z # label(non_clause) # label(goal).  [goal].
2 (x * e) * x = x.  [assumption].
3 x * (x * y) = y.  [assumption].
4 (x * y) * (z * u) = (x * z) * (y * u).  [assumption].
5 ((x * x) * x) * x = e.  [assumption].
6 c3 * c2 = c1 * c2.  [deny(1)].
7 c3 != c1.  [deny(1)].
8 e * e = e.  [para(2(a,1),2(a,1,1)),rewrite([3(5)]),flip(a)].
9 ((x * y) * x) * (e * y) = x * y.  [para(4(a,1),2(a,1))].
13 (x * y) * ((x * z) * u) = z * (y * u).  [para(3(a,1),4(a,1,1)),flip(a)].
17 ((x * x) * x) * e = x.  [para(5(a,1),3(a,1,2))].
36 (x * y) * (e * (y * x)) = x.  [para(3(a,1),9(a,1,1,1)),rewrite([3(7)])].
44 (x * y) * x = e * (y * x).  [para(36(a,1),3(a,1,2))].
49 x * (e * (x * x)) = e * (x * x).  [para(5(a,1),36(a,1,1)),rewrite([44(4),3(8),44(6)])].
50 e * ((x * x) * e) = x.  [para(5(a,1),36(a,1,2,2)),rewrite([44(2),49(4),8(6),44(5)])].
51 (c1 * c2) * (e * (c2 * c3)) = c3.  [para(6(a,1),36(a,1,1))].
53 (x * x) * (e * x) = e.  [para(17(a,1),36(a,1,2,2)),rewrite([44(3),3(5)])].
79 (x * x) * e = e * x.  [para(50(a,1),3(a,1,2)),flip(a)].
194 (c1 * e) * c3 = c3.  [para(51(a,1),4(a,1)),rewrite([3(9)]),flip(a)].
201 (c3 * (c1 * e)) * (e * c3) = c3.  [para(194(a,1),36(a,1,2,2))].
249 (x * y) * e = x * (y * (e * x)).  [para(53(a,1),13(a,1,2))].
257 (x * y) * (e * x) = x * (y * e).  [para(79(a,1),13(a,1,2))].
359 c3 * (c1 * c1) = c3.  [back_rewrite(201),rewrite([257(9),249(6),3(7)])].
361 c3 * c3 = c1 * c1.  [para(359(a,1),3(a,1,2))].
375 c3 = c1.  [para(361(a,1),36(a,1,1)),rewrite([361(7),36(9)]),flip(a)].
376 $F.  [resolve(375,a,7,a)].

============================== end of proof ==========================

============================== STATISTICS ============================

Given=29. Generated=940. Kept=374. proofs=1.
Usable=18. Sos=263. Demods=157. Limbo=1, Disabled=97. Hints=0.
Kept_by_rule=0, Deleted_by_rule=0.
Forward_subsumed=566. Back_subsumed=2.
Sos_limit_deleted=0. Sos_displaced=0. Sos_removed=0.
New_demodulators=230 (0 lex), Back_demodulated=89. Back_unit_deleted=0.
Demod_attempts=11924. Demod_rewrites=1264.
Res_instance_prunes=0. Para_instance_prunes=0. Basic_paramod_prunes=0.
Nonunit_fsub_feature_tests=0. Nonunit_bsub_feature_tests=0.
Megabytes=0.35.
User_CPU=0.04, System_CPU=0.00, Wall_clock=0.

============================== end of statistics =====================

============================== end of search =========================

THEOREM PROVED

Exiting with 1 proof.

Process 11137 exit (max_proofs) Wed Feb 25 09:31:05 2009
