%------------------------------------------------------------------------------
% File : Prover9---2026-6A
% Problem : PUZ020-1 : TPTP v9.3.1. Released v1.0.0.
% Transfm : none
% Format : tptp:raw
% Command : prover9 -casc 300 -f /export/starexec/sandbox/benchmark/theBenchmark.p
% Computer : n001.cluster.edu
% Model : x86_64 x86_64
% CPU : Intel(R) Xeon(R) CPU E5-2620 v4 2.10GHz
% Memory : 8046.5625MB
% OS : Linux 6.8.0-71-generic
% CPULimit : 300s
% WCLimit : 300s
% DateTime : Sun Sep 27 08:23:07 AM UTC 2026
% Result : Unsatisfiable 0.12s 0.37s
% Output : CNFRefutation 0.12s
% Verified :
% SZS Type : Refutation
% Derivation depth : 5
% Number of leaves : 5
% Syntax : Number of formulae : 15 ( 8 unt; 0 def)
% Number of atoms : 24 ( 0 equ)
% Maximal formula atoms : 3 ( 1 avg)
% Number of connectives : 20 ( 11 ~; 9 |; 0 &)
% ( 0 <=>; 0 =>; 0 <=; 0 <~>)
% Maximal formula depth : 5 ( 2 avg)
% Maximal term depth : 2 ( 1 avg)
% Number of predicates : 4 ( 3 usr; 1 prp; 0-1 aty)
% Number of functors : 3 ( 3 usr; 2 con; 0-1 aty)
% Number of variables : 2 ( 0 sgn 1 !; 0 ?)
% Comments :
%------------------------------------------------------------------------------
fof(husband,axiom,
person(husband),
file('theBenchmark.p',husband) ).
cnf(c_1,plain,
person(husband),
inference(clausify,[status(thm)],[husband]) ).
fof(knights_make_true_statements,axiom,
! [VAR_0] :
( knight(VAR_0)
| ~ a_truth(statement_by(VAR_0))
| ~ person(VAR_0) ),
file('theBenchmark.p',knights_make_true_statements) ).
cnf(c_3,plain,
( knight(A)
| ~ a_truth(statement_by(A))
| ~ person(A) ),
inference(clausify,[status(thm)],[knights_make_true_statements]) ).
fof(knight_wife_or_truthful_husband,axiom,
( knight(wife)
| a_truth(statement_by(husband)) ),
file('theBenchmark.p',knight_wife_or_truthful_husband) ).
cnf(c_21,plain,
( knight(wife)
| a_truth(statement_by(husband)) ),
inference(clausify,[status(thm)],[knight_wife_or_truthful_husband]) ).
fof(knight_wife_means_truthful_husband,axiom,
( a_truth(statement_by(husband))
| ~ knight(wife) ),
file('theBenchmark.p',knight_wife_means_truthful_husband) ).
cnf(c_22,plain,
( a_truth(statement_by(husband))
| ~ knight(wife) ),
inference(clausify,[status(thm)],[knight_wife_means_truthful_husband]) ).
fof(prove_knight_husband,axiom,
~ knight(husband),
file('theBenchmark.p',prove_knight_husband) ).
cnf(c_23,plain,
~ knight(husband),
inference(clausify,[status(thm)],[prove_knight_husband]) ).
cnf(c_25,plain,
( knight(husband)
| ~ a_truth(statement_by(husband)) ),
inference(resolve,[status(thm)],[c_1,c_3]) ).
cnf(c_26,plain,
~ a_truth(statement_by(husband)),
inference(resolve,[status(thm)],[c_23,c_25]) ).
cnf(c_37,plain,
~ knight(wife),
inference(resolve,[status(thm)],[c_26,c_22]) ).
cnf(c_39,plain,
knight(wife),
inference(resolve,[status(thm)],[c_26,c_21]) ).
cnf(c_38,plain,
$false,
inference(resolve,[status(thm)],[c_37,c_39]) ).
%------------------------------------------------------------------------------
%----ORIGINAL SYSTEM OUTPUT
% 0.00/0.02 % Problem : PUZ020-1 : TPTP v9.3.1. Released v1.0.0.
% 0.00/0.04 % Command : prover9 -casc 300 -f /export/starexec/sandbox/benchmark/theBenchmark.p
% 0.08/0.35 % Computer : n001.cluster.edu
% 0.08/0.35 % Model : x86_64 x86_64
% 0.08/0.35 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
% 0.08/0.35 % Memory : 8046.5625MB
% 0.08/0.35 % OS : Linux 6.8.0-71-generic
% 0.08/0.35 % CPULimit : 300
% 0.08/0.35 % WCLimit : 300
% 0.08/0.35 % DateTime : Sat Sep 26 05:11:12 UTC 2026
% 0.08/0.35 % CPUTime :
% 0.08/0.36 % Prover9 (64) version 2026-6A, July 2026, CASC-J13.
% 0.08/0.36 % Process 968428 was started by sandbox on n001,
% 0.08/0.36 % Sat Sep 26 05:11:12 2026
% 0.08/0.36 % The command was "/export/starexec/sandbox/solver/bin/prover9 -casc 300 -f /export/starexec/sandbox/benchmark/theBenchmark.p".
% 0.12/0.36
% 0.12/0.36 % From the command line: assign(max_seconds, 300).
% 0.12/0.37
% 0.12/0.37 % SZS status Unsatisfiable for theBenchmark
% 0.12/0.37
% 0.12/0.37 % Proof 1 at 0.00 (+ 0.00) seconds.
% 0.12/0.37 % Length of proof is 9.
% 0.12/0.37 % Level of proof is 4.
% 0.12/0.37 % Maximum clause weight is 5.000.
% 0.12/0.37 % Given clauses 0.
% 0.12/0.37
% 0.12/0.37 % SZS output start CNFRefutation for theBenchmark
% See solution above
%------------------------------------------------------------------------------