%------------------------------------------------------------------------------
% File : DT2H2X---1.9.5
% Problem : PUZ083^1 : TPTP v9.2.1. Released v3.6.0.
% Transfm : none
% Format : tptp:raw
% Command : /export/starexec/sandbox/solver/bin/run_DT2H2X /export/starexec/sandbox/benchmark/theBenchmark.p 300
% Computer : n007.cluster.edu
% Model : x86_64 x86_64
% CPU : Intel(R) Xeon(R) CPU E5-2620 v4 2.10GHz
% Memory : 8042.1875MB
% OS : Linux 3.10.0-693.el7.x86_64
% CPULimit : 300s
% WCLimit : 300s
% DateTime : Wed Feb 25 09:28:26 AM UTC 2026
% Result : Theorem 1.67s 1.41s
% Output : Refutation 1.67s
% Verified :
% SZS Type : Refutation
% Derivation depth : 21
% Number of leaves : 2
% Syntax : Number of formulae : 28 ( 14 unt; 0 typ; 0 def)
% Number of atoms : 133 ( 31 equ; 0 cnn)
% Maximal formula atoms : 4 ( 4 avg)
% Number of connectives : 120 ( 24 ~; 7 |; 0 &; 66 @)
% ( 0 <=>; 17 =>; 0 <=; 0 <~>)
% Maximal formula depth : 7 ( 3 avg)
% Number of types : 2 ( 0 usr)
% Number of type conns : 0 ( 0 >; 0 *; 0 +; 0 <<)
% Number of symbols : 8 ( 4 usr; 5 con; 0-2 aty)
% ( 6 !!; 0 ??; 0 @@+; 0 @@-)
% Number of variables : 21 ( 8 ^; 13 !; 0 ?; 21 :)
% Comments :
%------------------------------------------------------------------------------
thf(func_def_1,type,
says: $i > $o > $o ).
thf(func_def_11,type,
ph1:
!>[X0: $tType] : X0 ).
thf(f44,plain,
$false,
inference(trivial_inequality_removal,[status(thm)],[f43]) ).
thf(f43,plain,
$true = $false,
inference(superposition,[status(thm)],[f27,f40]) ).
thf(f40,plain,
$false = sK2,
inference(trivial_inequality_removal,[status(thm)],[f35]) ).
thf(f35,plain,
( ( $false = sK2 )
| ( $true = $false ) ),
inference(superposition,[status(thm)],[f26,f18]) ).
thf(f18,plain,
! [X1: $o] :
( ( $false
= ( says @ peter @ X1 ) )
| ( $false = X1 ) ),
inference(not_proxy_clausification,[status(thm)],[f17]) ).
thf(f17,plain,
! [X1: $o] :
( ( $true = ( ~ X1 ) )
| ( $false
= ( says @ peter @ X1 ) ) ),
inference(binary_proxy_clausification,[status(thm)],[f16]) ).
thf(f16,plain,
! [X1: $o] :
( $true
= ( ( says @ peter @ X1 )
=> ~ X1 ) ),
inference(beta_eta_normalization,[status(thm)],[f15]) ).
thf(f15,plain,
! [X1: $o] :
( $true
= ( ^ [Y0: $o] :
( ( says @ peter @ Y0 )
=> ~ Y0 )
@ X1 ) ),
inference(pi_clausification,[status(thm)],[f14]) ).
thf(f14,plain,
( ( !! @ $o
@ ^ [Y0: $o] :
( ( says @ peter @ Y0 )
=> ~ Y0 ) )
= $true ),
inference(trivial_inequality_removal,[status(thm)],[f13]) ).
thf(f13,plain,
( ( $true != $true )
| ( ( !! @ $o
@ ^ [Y0: $o] :
( ( says @ peter @ Y0 )
=> ~ Y0 ) )
= $true ) ),
inference(superposition,[status(thm)],[f11,f12]) ).
thf(f12,plain,
( $true
= ( says @ peter
@ ( !! @ $o
@ ^ [Y0: $o] :
( ( says @ peter @ Y0 )
=> ~ Y0 ) ) ) ),
inference(cnf_transformation,[status(thm)],[f6]) ).
thf(f6,plain,
( $true
= ( says @ peter
@ ( !! @ $o
@ ^ [Y0: $o] :
( ( says @ peter @ Y0 )
=> ~ Y0 ) ) ) ),
inference(fool_elimination,[status(thm)],[f5]) ).
thf(f5,plain,
( says @ peter
@ ! [X0: $o] :
( ( says @ peter @ X0 )
=> ~ X0 ) ),
inference(rectify,[status(thm)],[f1]) ).
thf(f1,axiom,
( says @ peter
@ ! [X0: $o] :
( ( says @ peter @ X0 )
=> ~ X0 ) ),
file('/export/starexec/sandbox/tmp/tmp.0boEcsDAkr/DTF2THF_19723.p',ax1) ).
thf(f11,plain,
! [X0: $o] :
( ( ( says @ peter @ X0 )
!= $true )
| ( $true = X0 ) ),
inference(cnf_transformation,[status(thm)],[f10]) ).
thf(f10,plain,
! [X0: $o] :
( ( $true = X0 )
| ( ( says @ peter @ X0 )
!= $true ) ),
inference(ennf_transformation,[status(thm)],[f9]) ).
thf(f9,plain,
! [X0: $o] :
( ( ( says @ peter @ X0 )
= $true )
=> ( $true = X0 ) ),
inference(flattening,[status(thm)],[f8]) ).
thf(f8,plain,
~ ~ ! [X0: $o] :
( ( ( says @ peter @ X0 )
= $true )
=> ( $true = X0 ) ),
inference(fool_elimination,[status(thm)],[f7]) ).
thf(f7,plain,
~ ~ ! [X0: $o] :
( ( says @ peter @ X0 )
=> X0 ),
inference(rectify,[status(thm)],[f3]) ).
thf(f3,negated_conjecture,
~ ~ ! [X0: $o] :
( ( says @ peter @ X0 )
=> X0 ),
inference(negated_conjecture,[status(cth)],[f2]) ).
thf(f2,conjecture,
~ ! [X0: $o] :
( ( says @ peter @ X0 )
=> X0 ),
file('/export/starexec/sandbox/tmp/tmp.0boEcsDAkr/DTF2THF_19723.p',thm) ).
thf(f26,plain,
( $true
= ( says @ peter @ sK2 ) ),
inference(binary_proxy_clausification,[status(thm)],[f24]) ).
thf(f24,plain,
( ( ( says @ peter @ sK2 )
=> ~ sK2 )
= $false ),
inference(beta_eta_normalization,[status(thm)],[f23]) ).
thf(f23,plain,
( $false
= ( ^ [Y0: $o] :
( ( says @ peter @ Y0 )
=> ~ Y0 )
@ sK2 ) ),
inference(sigma_clausification,[status(thm)],[f22]) ).
thf(f22,plain,
( ( !! @ $o
@ ^ [Y0: $o] :
( ( says @ peter @ Y0 )
=> ~ Y0 ) )
= $false ),
inference(trivial_inequality_removal,[status(thm)],[f21]) ).
thf(f21,plain,
( ( ( !! @ $o
@ ^ [Y0: $o] :
( ( says @ peter @ Y0 )
=> ~ Y0 ) )
= $false )
| ( $true = $false ) ),
inference(superposition,[status(thm)],[f12,f18]) ).
thf(f27,plain,
$true = sK2,
inference(not_proxy_clausification,[status(thm)],[f25]) ).
thf(f25,plain,
( $false = ( ~ sK2 ) ),
inference(binary_proxy_clausification,[status(thm)],[f24]) ).
%------------------------------------------------------------------------------
%----ORIGINAL SYSTEM OUTPUT
% 0.00/0.11 % Problem : PUZ083^1 : TPTP v9.2.1. Released v3.6.0.
% 0.12/0.13 % Command : /export/starexec/sandbox/solver/bin/run_DT2H2X /export/starexec/sandbox/benchmark/theBenchmark.p 300
% 0.16/0.33 % Computer : n007.cluster.edu
% 0.16/0.33 % Model : x86_64 x86_64
% 0.16/0.33 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
% 0.16/0.33 % Memory : 8042.1875MB
% 0.16/0.33 % OS : Linux 3.10.0-693.el7.x86_64
% 0.16/0.33 % CPULimit : 300
% 0.16/0.33 % WCLimit : 300
% 0.16/0.33 % DateTime : Tue Feb 24 11:32:08 EST 2026
% 0.16/0.33 % CPUTime :
% 0.16/0.33 Running /export/starexec/sandbox/solver/bin/run_DT2H2X /export/starexec/sandbox/benchmark/theBenchmark.p 300
% 0.22/0.44 ---- Original DTF file ---
% 0.22/0.44 thf(spec,logic,$$dhol).
% 0.22/0.44 %------------------------------------------------------------------------------
% 0.22/0.44 % File : PUZ083^1 : TPTP v9.2.1. Released v3.6.0.
% 0.22/0.44 % Domain : Puzzles
% 0.22/0.44 % Problem : Peter the untruthful
% 0.22/0.44 % Version : Especial.
% 0.22/0.44 % English : Peter says that everything he says is false. Show that not
% 0.22/0.44 % everything Peter says is true.
% 0.22/0.44
% 0.22/0.44 % Refs : [Ben08] Benzmueller (2008), Email to G. Sutcliffe
% 0.22/0.44 % Source : [Ben08]
% 0.22/0.44 % Names :
% 0.22/0.44
% 0.22/0.44 % Status : Theorem
% 0.22/0.44 % Rating : 0.17 v9.1.0, 0.12 v9.0.0, 0.17 v8.2.0, 0.18 v8.1.0, 0.08 v7.4.0, 0.11 v7.3.0, 0.10 v7.2.0, 0.12 v7.1.0, 0.14 v7.0.0, 0.12 v6.4.0, 0.14 v6.3.0, 0.17 v6.2.0, 0.00 v5.4.0, 0.25 v5.3.0, 0.50 v5.2.0, 0.25 v5.1.0, 0.50 v4.1.0, 0.67 v3.7.0
% 0.22/0.44 % Syntax : Number of formulae : 4 ( 1 unt; 2 typ; 0 def)
% 0.22/0.44 % Number of atoms : 3 ( 0 equ; 0 cnn)
% 0.22/0.44 % Maximal formula atoms : 2 ( 1 avg)
% 0.22/0.44 % Number of connectives : 10 ( 2 ~; 0 |; 0 &; 6 @)
% 0.22/0.44 % ( 0 <=>; 2 =>; 0 <=; 0 <~>)
% 0.22/0.44 % Maximal formula depth : 6 ( 6 avg)
% 0.22/0.44 % Number of types : 2 ( 0 usr)
% 0.22/0.44 % Number of type conns : 2 ( 2 >; 0 *; 0 +; 0 <<)
% 0.22/0.44 % Number of symbols : 2 ( 2 usr; 1 con; 0-2 aty)
% 0.22/0.44 % Number of variables : 2 ( 0 ^; 2 !; 0 ?; 2 :)
% 0.22/0.44 % SPC : TH0_THM_NEQ_NAR
% 0.22/0.44
% 0.22/0.44 % Comments : Isabelle solves this with blast and import of HOL (not Main)
% 0.22/0.44 %------------------------------------------------------------------------------
% 0.22/0.44 %----Signature
% 0.22/0.44 thf(peter,type,
% 0.22/0.44 peter: $i ).
% 0.22/0.44
% 0.22/0.44 thf(says,type,
% 0.22/0.44 says: $i > $o > $o ).
% 0.22/0.44
% 0.22/0.44 %----Axioms
% 0.22/0.44 thf(ax1,axiom,
% 0.22/0.44 ( says @ peter
% 0.22/0.44 @ ! [X: $o] :
% 0.22/0.44 ( ( says @ peter @ X )
% 0.22/0.44 => ~ X ) ) ).
% 0.22/0.44
% 0.22/0.44 thf(thm,conjecture,
% 0.22/0.44 ~ ! [X: $o] :
% 0.22/0.44 ( ( says @ peter @ X )
% 0.22/0.44 => X ) ).
% 0.22/0.44
% 0.22/0.44 %------------------------------------------------------------------------------
% 0.22/0.44 ------------------------
% 1.49/1.38 ---- Embedded in THF ---
% 1.49/1.38 %%% This output was generated by embedproblem, version 1.9.5 (library version 1.9).
% 1.49/1.38 %%% Generated on Tue Feb 24 11:32:09 EST 2026
% 1.49/1.38 %%% using '$$dhol' embedding, version 1.3.0.
% 1.49/1.38 %%% Logic specification used:
% 1.49/1.38 %%% thf(spec, logic, $$dhol).
% 1.49/1.38
% 1.49/1.38 % SZS output start ListOfTHF for /export/starexec/sandbox/tmp/tmp.0boEcsDAkr/DTF2DTF19723.p
% See solution above
% 1.49/1.38 ------------------------
% 1.49/1.38 ---- Cleaned THF ---
% 1.49/1.39 thf(peter,type,
% 1.49/1.39 peter: $i ).
% 1.49/1.39
% 1.49/1.39 thf(says,type,
% 1.49/1.39 says: $i > $o > $o ).
% 1.49/1.39
% 1.49/1.39 thf(ax1,axiom,
% 1.49/1.39 ( says @ peter
% 1.49/1.39 @ ! [X: $o] :
% 1.49/1.39 ( ( says @ peter @ X )
% 1.49/1.39 => ~ X ) ) ).
% 1.49/1.39
% 1.49/1.39 thf(thm,conjecture,
% 1.49/1.39 ~ ! [X: $o] :
% 1.49/1.39 ( ( says @ peter @ X )
% 1.49/1.39 => X ) ).
% 1.49/1.39 ------------------------
% 1.67/1.40 % (19822)lrs+10_1:1_c=on:cnfonf=conj_eager:fd=off:fe=off:kws=frequency:spb=intro:i=4:si=on:rtra=on_0 on DTF2THF_19723 for (3000ds/4Mi)
% 1.67/1.40 % (19821)lrs+1002_1:8_bd=off:fd=off:hud=10:tnu=1:i=183:si=on:rtra=on_0 on DTF2THF_19723 for (3000ds/183Mi)
% 1.67/1.40 % (19824)lrs+10_1:1_au=on:inj=on:i=2:si=on:rtra=on_0 on DTF2THF_19723 for (3000ds/2Mi)
% 1.67/1.40 % (19825)lrs+1002_1:128_aac=none:au=on:cnfonf=lazy_not_gen_be_off:sos=all:i=2:si=on:rtra=on_0 on DTF2THF_19723 for (3000ds/2Mi)
% 1.67/1.40 % (19826)lrs+1002_1:1_au=on:bd=off:e2e=on:sd=2:sos=on:ss=axioms:i=275:si=on:rtra=on_0 on DTF2THF_19723 for (3000ds/275Mi)
% 1.67/1.41 % (19827)lrs+1004_1:128_cond=on:e2e=on:sp=weighted_frequency:i=18:si=on:rtra=on_0 on DTF2THF_19723 for (3000ds/18Mi)
% 1.67/1.41 % (19823)dis+1010_1:1_au=on:cbe=off:chr=on:fsr=off:hfsq=on:nm=64:sos=theory:sp=weighted_frequency:i=27:si=on:rtra=on_0 on DTF2THF_19723 for (3000ds/27Mi)
% 1.67/1.41 % (19826)Refutation not found, incomplete strategy
% 1.67/1.41 % (19826)------------------------------
% 1.67/1.41 % (19826)Version: Vampire 4.8 (commit 7b44b1c2f on 2025-07-15 09:50:17 +0100)
% 1.67/1.41 % (19826)Termination reason: Refutation not found, incomplete strategy
% 1.67/1.41
% 1.67/1.41
% 1.67/1.41 % (19826)Memory used [KB]: 5373
% 1.67/1.41 % (19826)Time elapsed: 0.002 s
% 1.67/1.41 % (19826)Instructions burned: 1 (million)
% 1.67/1.41 % (19826)------------------------------
% 1.67/1.41 % (19826)------------------------------
% 1.67/1.41 % (19824)Instruction limit reached!
% 1.67/1.41 % (19824)------------------------------
% 1.67/1.41 % (19824)Version: Vampire 4.8 (commit 7b44b1c2f on 2025-07-15 09:50:17 +0100)
% 1.67/1.41 % (19824)Termination reason: Unknown
% 1.67/1.41 % (19824)Termination phase: Saturation
% 1.67/1.41 % (19825)Instruction limit reached!
% 1.67/1.41 % (19825)------------------------------
% 1.67/1.41 % (19825)Version: Vampire 4.8 (commit 7b44b1c2f on 2025-07-15 09:50:17 +0100)
% 1.67/1.41 % (19825)Termination reason: Unknown
% 1.67/1.41 % (19825)Termination phase: Saturation
% 1.67/1.41
% 1.67/1.41 % (19825)Memory used [KB]: 5500
% 1.67/1.41 % (19825)Time elapsed: 0.003 s
% 1.67/1.41 % (19825)Instructions burned: 2 (million)
% 1.67/1.41 % (19825)------------------------------
% 1.67/1.41 % (19825)------------------------------
% 1.67/1.41
% 1.67/1.41 % (19824)Memory used [KB]: 5500
% 1.67/1.41 % (19824)Time elapsed: 0.003 s
% 1.67/1.41 % (19824)Instructions burned: 2 (million)
% 1.67/1.41 % (19824)------------------------------
% 1.67/1.41 % (19824)------------------------------
% 1.67/1.41 % (19821)First to succeed.
% 1.67/1.41 % (19827)Also succeeded, but the first one will report.
% 1.67/1.41 % (19822)Instruction limit reached!
% 1.67/1.41 % (19822)------------------------------
% 1.67/1.41 % (19822)Version: Vampire 4.8 (commit 7b44b1c2f on 2025-07-15 09:50:17 +0100)
% 1.67/1.41 % (19822)Termination reason: Unknown
% 1.67/1.41 % (19822)Termination phase: Saturation
% 1.67/1.41
% 1.67/1.41 % (19822)Memory used [KB]: 5500
% 1.67/1.41 % (19822)Time elapsed: 0.005 s
% 1.67/1.41 % (19822)Instructions burned: 5 (million)
% 1.67/1.41 % (19822)------------------------------
% 1.67/1.41 % (19822)------------------------------
% 1.67/1.41 % (19821)Refutation found. Thanks to Tanya!
% 1.67/1.41 % SZS status Theorem for DTF2THF_19723
% 1.67/1.41 % SZS output start Proof for DTF2THF_19723
% 1.67/1.41 thf(func_def_1, type, says: $i > $o > $o).
% 1.67/1.41 thf(func_def_11, type, ph1: !>[X0: $tType]:(X0)).
% 1.67/1.41 thf(f44,plain,(
% 1.67/1.41 $false),
% 1.67/1.41 inference(trivial_inequality_removal,[status(thm)],[f43])).
% 1.67/1.41 thf(f43,plain,(
% 1.67/1.41 ($true = $false)),
% 1.67/1.41 inference(superposition,[status(thm)],[f27,f40])).
% 1.67/1.41 thf(f40,plain,(
% 1.67/1.41 ($false = sK2)),
% 1.67/1.41 inference(trivial_inequality_removal,[status(thm)],[f35])).
% 1.67/1.41 thf(f35,plain,(
% 1.67/1.41 ($false = sK2) | ($true = $false)),
% 1.67/1.41 inference(superposition,[status(thm)],[f26,f18])).
% 1.67/1.41 thf(f18,plain,(
% 1.67/1.41 ( ! [X1 : $o] : (($false = (says @ peter @ X1)) | ($false = X1)) )),
% 1.67/1.41 inference(not_proxy_clausification,[status(thm)],[f17])).
% 1.67/1.41 thf(f17,plain,(
% 1.67/1.41 ( ! [X1 : $o] : (($true = (~ X1)) | ($false = (says @ peter @ X1))) )),
% 1.67/1.41 inference(binary_proxy_clausification,[status(thm)],[f16])).
% 1.67/1.41 thf(f16,plain,(
% 1.67/1.41 ( ! [X1 : $o] : (($true = ((says @ peter @ X1) => (~ X1)))) )),
% 1.67/1.41 inference(beta_eta_normalization,[status(thm)],[f15])).
% 1.67/1.41 thf(f15,plain,(
% 1.67/1.41 ( ! [X1 : $o] : (($true = ((^[Y0 : $o]: ((says @ peter @ Y0) => (~ Y0))) @ X1))) )),
% 1.67/1.41 inference(pi_clausification,[status(thm)],[f14])).
% 1.67/1.41 thf(f14,plain,(
% 1.67/1.41 ((!! @ $o @ (^[Y0 : $o]: ((says @ peter @ Y0) => (~ Y0)))) = $true)),
% 1.67/1.41 inference(trivial_inequality_removal,[status(thm)],[f13])).
% 1.67/1.41 thf(f13,plain,(
% 1.67/1.41 ($true != $true) | ((!! @ $o @ (^[Y0 : $o]: ((says @ peter @ Y0) => (~ Y0)))) = $true)),
% 1.67/1.41 inference(superposition,[status(thm)],[f11,f12])).
% 1.67/1.41 thf(f12,plain,(
% 1.67/1.41 ($true = (says @ peter @ (!! @ $o @ (^[Y0 : $o]: ((says @ peter @ Y0) => (~ Y0))))))),
% 1.67/1.41 inference(cnf_transformation,[status(thm)],[f6])).
% 1.67/1.41 thf(f6,plain,(
% 1.67/1.41 ($true = (says @ peter @ (!! @ $o @ (^[Y0 : $o]: ((says @ peter @ Y0) => (~ Y0))))))),
% 1.67/1.41 inference(fool_elimination,[status(thm)],[f5])).
% 1.67/1.41 thf(f5,plain,(
% 1.67/1.41 (says @ peter @ ! [X0 : $o] : ((says @ peter @ X0) => ~X0))),
% 1.67/1.41 inference(rectify,[status(thm)],[f1])).
% 1.67/1.41 thf(f1,axiom,(
% 1.67/1.41 (says @ peter @ ! [X0 : $o] : ((says @ peter @ X0) => ~X0))),
% 1.67/1.41 file('/export/starexec/sandbox/tmp/tmp.0boEcsDAkr/DTF2THF_19723.p',ax1)).
% 1.67/1.41 thf(f11,plain,(
% 1.67/1.41 ( ! [X0 : $o] : (((says @ peter @ X0) != $true) | ($true = X0)) )),
% 1.67/1.41 inference(cnf_transformation,[status(thm)],[f10])).
% 1.67/1.41 thf(f10,plain,(
% 1.67/1.41 ! [X0 : $o] : (($true = X0) | ((says @ peter @ X0) != $true))),
% 1.67/1.41 inference(ennf_transformation,[status(thm)],[f9])).
% 1.67/1.41 thf(f9,plain,(
% 1.67/1.41 ! [X0 : $o] : (((says @ peter @ X0) = $true) => ($true = X0))),
% 1.67/1.41 inference(flattening,[status(thm)],[f8])).
% 1.67/1.41 thf(f8,plain,(
% 1.67/1.41 ~~! [X0 : $o] : (((says @ peter @ X0) = $true) => ($true = X0))),
% 1.67/1.41 inference(fool_elimination,[status(thm)],[f7])).
% 1.67/1.41 thf(f7,plain,(
% 1.67/1.41 ~~! [X0 : $o] : ((says @ peter @ X0) => X0)),
% 1.67/1.41 inference(rectify,[status(thm)],[f3])).
% 1.67/1.41 thf(f3,negated_conjecture,(
% 1.67/1.41 ~~! [X0 : $o] : ((says @ peter @ X0) => X0)),
% 1.67/1.41 inference(negated_conjecture,[status(cth)],[f2])).
% 1.67/1.41 thf(f2,conjecture,(
% 1.67/1.41 ~! [X0 : $o] : ((says @ peter @ X0) => X0)),
% 1.67/1.41 file('/export/starexec/sandbox/tmp/tmp.0boEcsDAkr/DTF2THF_19723.p',thm)).
% 1.67/1.41 thf(f26,plain,(
% 1.67/1.41 ($true = (says @ peter @ sK2))),
% 1.67/1.41 inference(binary_proxy_clausification,[status(thm)],[f24])).
% 1.67/1.41 thf(f24,plain,(
% 1.67/1.41 (((says @ peter @ sK2) => (~ sK2)) = $false)),
% 1.67/1.41 inference(beta_eta_normalization,[status(thm)],[f23])).
% 1.67/1.41 thf(f23,plain,(
% 1.67/1.41 ($false = ((^[Y0 : $o]: ((says @ peter @ Y0) => (~ Y0))) @ sK2))),
% 1.67/1.41 inference(sigma_clausification,[status(thm)],[f22])).
% 1.67/1.41 thf(f22,plain,(
% 1.67/1.41 ((!! @ $o @ (^[Y0 : $o]: ((says @ peter @ Y0) => (~ Y0)))) = $false)),
% 1.67/1.41 inference(trivial_inequality_removal,[status(thm)],[f21])).
% 1.67/1.41 thf(f21,plain,(
% 1.67/1.41 ((!! @ $o @ (^[Y0 : $o]: ((says @ peter @ Y0) => (~ Y0)))) = $false) | ($true = $false)),
% 1.67/1.41 inference(superposition,[status(thm)],[f12,f18])).
% 1.67/1.41 thf(f27,plain,(
% 1.67/1.41 ($true = sK2)),
% 1.67/1.41 inference(not_proxy_clausification,[status(thm)],[f25])).
% 1.67/1.41 thf(f25,plain,(
% 1.67/1.41 ($false = (~ sK2))),
% 1.67/1.41 inference(binary_proxy_clausification,[status(thm)],[f24])).
% 1.67/1.41 % SZS output end Proof for DTF2THF_19723
% 1.67/1.41 % (19821)------------------------------
% 1.67/1.41 % (19821)Version: Vampire 4.8 (commit 7b44b1c2f on 2025-07-15 09:50:17 +0100)
% 1.67/1.41 % (19821)Termination reason: Refutation
% 1.67/1.41
% 1.67/1.41 % (19821)Memory used [KB]: 5500
% 1.67/1.41 % (19821)Time elapsed: 0.004 s
% 1.67/1.41 % (19821)Instructions burned: 3 (million)
% 1.67/1.41 % (19821)------------------------------
% 1.67/1.41 % (19821)------------------------------
% 1.67/1.41 % (19820)Success in time 0.018 s
%------------------------------------------------------------------------------