%------------------------------------------------------------------------------
% File : Prover9---2026-6A
% Problem : PUZ008-1 : 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 : n020.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 08:22:43 AM UTC 2026
% Result : Unsatisfiable 0.11s 0.39s
% Output : CNFRefutation 0.11s
% Verified :
% SZS Type : Refutation
% Derivation depth : 3
% Number of leaves : 3
% Syntax : Number of formulae : 8 ( 6 unt; 0 def)
% Number of atoms : 10 ( 0 equ)
% Maximal formula atoms : 2 ( 1 avg)
% Number of connectives : 6 ( 4 ~; 2 |; 0 &)
% ( 0 <=>; 0 =>; 0 <=; 0 <~>)
% Maximal formula depth : 7 ( 3 avg)
% Maximal term depth : 6 ( 2 avg)
% Number of predicates : 2 ( 1 usr; 1 prp; 0-3 aty)
% Number of functors : 8 ( 8 usr; 3 con; 0-2 aty)
% Number of variables : 21 ( 6 sgn 9 !; 0 ?)
% Comments :
%------------------------------------------------------------------------------
fof(missionary_west_to_east,axiom,
! [VAR_0,VAR_1,VAR_2,VAR_3] :
( achievable(west(m(VAR_0),c(VAR_1)),boatoneast,east(m(s(VAR_2)),c(VAR_3)))
| ~ achievable(west(m(s(VAR_0)),c(VAR_1)),boatonwest,east(m(VAR_2),c(VAR_3))) ),
file('theBenchmark.p',missionary_west_to_east) ).
cnf(c_5,plain,
( achievable(west(m(A),c(B)),boatoneast,east(m(s(C)),c(D)))
| ~ achievable(west(m(s(A)),c(B)),boatonwest,east(m(C),c(D))) ),
inference(clausify,[status(thm)],[missionary_west_to_east]) ).
fof(extra_cannibal_meal_on_east_bank,axiom,
! [VAR_0,VAR_1,VAR_2,VAR_3] : achievable(west(VAR_0,VAR_1),VAR_2,east(m(s(VAR_3)),c(s(s(VAR_3))))),
file('theBenchmark.p',extra_cannibal_meal_on_east_bank) ).
cnf(c_13,plain,
achievable(west(A,B),C,east(m(s(D)),c(s(s(D))))),
inference(clausify,[status(thm)],[extra_cannibal_meal_on_east_bank]) ).
fof(prove_can_get_to_east_bank,axiom,
! [VAR_0] : ~ achievable(west(m(n0),c(n0)),VAR_0,east(m(s(s(s(n0)))),c(s(s(s(n0)))))),
file('theBenchmark.p',prove_can_get_to_east_bank) ).
cnf(c_16,plain,
~ achievable(west(m(n0),c(n0)),A,east(m(s(s(s(n0)))),c(s(s(s(n0)))))),
inference(clausify,[status(thm)],[prove_can_get_to_east_bank]) ).
cnf(c_32,plain,
achievable(west(m(A),c(B)),boatoneast,east(m(s(s(C))),c(s(s(C))))),
inference(resolve,[status(thm)],[c_5,c_13]) ).
cnf(c_33,plain,
$false,
inference(resolve,[status(thm)],[c_32,c_16]) ).
%------------------------------------------------------------------------------
%----ORIGINAL SYSTEM OUTPUT
% 0.00/0.03 % Problem : PUZ008-1 : TPTP v9.3.1. Released v1.0.0.
% 0.00/0.04 % Command : prover9 -casc 300 -f /export/starexec/sandbox/benchmark/theBenchmark.p
% 0.11/0.37 % Computer : n020.cluster.edu
% 0.11/0.37 % Model : x86_64 x86_64
% 0.11/0.37 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
% 0.11/0.37 % Memory : 8046.5625MB
% 0.11/0.37 % OS : Linux 6.8.0-71-generic
% 0.11/0.37 % CPULimit : 300
% 0.11/0.37 % WCLimit : 300
% 0.11/0.37 % DateTime : Sat Sep 26 05:04:03 UTC 2026
% 0.11/0.37 % CPUTime :
% 0.11/0.37 % Prover9 (64) version 2026-6A, July 2026, CASC-J13.
% 0.11/0.37 % Process 667264 was started by sandbox on n020,
% 0.11/0.37 % Sat Sep 26 05:04:03 2026
% 0.11/0.37 % The command was "/export/starexec/sandbox/solver/bin/prover9 -casc 300 -f /export/starexec/sandbox/benchmark/theBenchmark.p".
% 0.11/0.38
% 0.11/0.38 % From the command line: assign(max_seconds, 300).
% 0.11/0.39
% 0.11/0.39 % SZS status Unsatisfiable for theBenchmark
% 0.11/0.39
% 0.11/0.39 % Proof 1 at 0.00 (+ 0.00) seconds.
% 0.11/0.39 % Length of proof is 5.
% 0.11/0.39 % Level of proof is 2.
% 0.11/0.39 % Maximum clause weight is 26.000.
% 0.11/0.39 % Given clauses 13.
% 0.11/0.39
% 0.11/0.39 % SZS output start CNFRefutation for theBenchmark
% See solution above
%------------------------------------------------------------------------------