TSTP Solution File: SET072-6 by Z3---4.8.9.0

View Problem - Process Solution

%------------------------------------------------------------------------------
% File     : Z3---4.8.9.0
% Problem  : SET072-6 : TPTP v8.1.0. Bugfixed v2.1.0.
% Transfm  : none
% Format   : tptp
% Command  : z3_tptp -proof -model -t:%d -file:%s

% Computer : n022.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 : Tue Sep 20 05:05:22 EDT 2022

% Result   : Unsatisfiable 0.19s 0.41s
% Output   : Proof 0.19s
% Verified : 
% SZS Type : Refutation
%            Derivation depth      :   14
%            Number of leaves      :   41
% Syntax   : Number of formulae    :   95 (  24 unt;   8 typ;   0 def)
%            Number of atoms       :  304 ( 113 equ)
%            Maximal formula atoms :   12 (   3 avg)
%            Number of connectives :  355 ( 143   ~; 175   |;   0   &)
%                                         (  37 <=>;   0  =>;   0  <=;   0 <~>)
%            Maximal formula depth :   10 (   5 avg)
%            Maximal term depth    :    2 (   1 avg)
%            Number of FOOLs       :    5 (   5 fml;   0 var)
%            Number of types       :    2 (   0 usr)
%            Number of type conns  :    8 (   4   >;   4   *;   0   +;   0  <<)
%            Number of predicates  :    5 (   3 usr;   1 prp; 0-2 aty)
%            Number of functors    :    7 (   7 usr;   4 con; 0-2 aty)
%            Number of variables   :  213 ( 197   !;   0   ?; 213   :)

% Comments : 
%------------------------------------------------------------------------------
tff(z_type,type,
    z: $i ).

tff(y_type,type,
    y: $i ).

tff(x_type,type,
    x: $i ).

tff(member_type,type,
    member: ( $i * $i ) > $o ).

tff(unordered_pair_type,type,
    unordered_pair: ( $i * $i ) > $i ).

tff(universal_class_type,type,
    universal_class: $i ).

tff(cross_product_type,type,
    cross_product: ( $i * $i ) > $i ).

tff(ordered_pair_type,type,
    ordered_pair: ( $i * $i ) > $i ).

tff(1,plain,
    ( ( y = x )
  <=> ( x = y ) ),
    inference(commutativity,[status(thm)],]) ).

tff(2,plain,
    ( ( unordered_pair(x,z) = unordered_pair(y,z) )
  <=> ( unordered_pair(x,z) = unordered_pair(y,z) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(3,axiom,
    unordered_pair(x,z) = unordered_pair(y,z),
    file('/export/starexec/sandbox2/benchmark/theBenchmark.p',prove_right_cancellation_1) ).

tff(4,plain,
    unordered_pair(x,z) = unordered_pair(y,z),
    inference(modus_ponens,[status(thm)],[3,2]) ).

tff(5,plain,
    unordered_pair(y,z) = unordered_pair(x,z),
    inference(symmetry,[status(thm)],[4]) ).

tff(6,plain,
    ( member(x,unordered_pair(y,z))
  <=> member(x,unordered_pair(x,z)) ),
    inference(monotonicity,[status(thm)],[5]) ).

tff(7,plain,
    ( member(x,unordered_pair(x,z))
  <=> member(x,unordered_pair(y,z)) ),
    inference(symmetry,[status(thm)],[6]) ).

tff(8,plain,
    ( member(ordered_pair(x,y),cross_product(universal_class,universal_class))
  <=> member(ordered_pair(x,y),cross_product(universal_class,universal_class)) ),
    inference(rewrite,[status(thm)],]) ).

tff(9,axiom,
    member(ordered_pair(x,y),cross_product(universal_class,universal_class)),
    file('/export/starexec/sandbox2/benchmark/theBenchmark.p',prove_right_cancellation_2) ).

tff(10,plain,
    member(ordered_pair(x,y),cross_product(universal_class,universal_class)),
    inference(modus_ponens,[status(thm)],[9,8]) ).

tff(11,plain,
    ^ [V: $i,Y: $i,U: $i,X: $i] :
      refl(
        ( ( ~ member(ordered_pair(U,V),cross_product(X,Y))
          | member(U,X) )
      <=> ( ~ member(ordered_pair(U,V),cross_product(X,Y))
          | member(U,X) ) )),
    inference(bind,[status(th)],]) ).

tff(12,plain,
    ( ! [V: $i,Y: $i,U: $i,X: $i] :
        ( ~ member(ordered_pair(U,V),cross_product(X,Y))
        | member(U,X) )
  <=> ! [V: $i,Y: $i,U: $i,X: $i] :
        ( ~ member(ordered_pair(U,V),cross_product(X,Y))
        | member(U,X) ) ),
    inference(quant_intro,[status(thm)],[11]) ).

tff(13,plain,
    ( ! [V: $i,Y: $i,U: $i,X: $i] :
        ( ~ member(ordered_pair(U,V),cross_product(X,Y))
        | member(U,X) )
  <=> ! [V: $i,Y: $i,U: $i,X: $i] :
        ( ~ member(ordered_pair(U,V),cross_product(X,Y))
        | member(U,X) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(14,axiom,
    ! [V: $i,Y: $i,U: $i,X: $i] :
      ( ~ member(ordered_pair(U,V),cross_product(X,Y))
      | member(U,X) ),
    file('/export/starexec/sandbox2/benchmark/Axioms/SET004-0.ax',cartesian_product1) ).

tff(15,plain,
    ! [V: $i,Y: $i,U: $i,X: $i] :
      ( ~ member(ordered_pair(U,V),cross_product(X,Y))
      | member(U,X) ),
    inference(modus_ponens,[status(thm)],[14,13]) ).

tff(16,plain,
    ! [V: $i,Y: $i,U: $i,X: $i] :
      ( ~ member(ordered_pair(U,V),cross_product(X,Y))
      | member(U,X) ),
    inference(skolemize,[status(sab)],[15]) ).

tff(17,plain,
    ! [V: $i,Y: $i,U: $i,X: $i] :
      ( ~ member(ordered_pair(U,V),cross_product(X,Y))
      | member(U,X) ),
    inference(modus_ponens,[status(thm)],[16,12]) ).

tff(18,plain,
    ( ( ~ ! [V: $i,Y: $i,U: $i,X: $i] :
            ( ~ member(ordered_pair(U,V),cross_product(X,Y))
            | member(U,X) )
      | ~ member(ordered_pair(x,y),cross_product(universal_class,universal_class))
      | member(x,universal_class) )
  <=> ( ~ ! [V: $i,Y: $i,U: $i,X: $i] :
            ( ~ member(ordered_pair(U,V),cross_product(X,Y))
            | member(U,X) )
      | ~ member(ordered_pair(x,y),cross_product(universal_class,universal_class))
      | member(x,universal_class) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(19,plain,
    ( ~ ! [V: $i,Y: $i,U: $i,X: $i] :
          ( ~ member(ordered_pair(U,V),cross_product(X,Y))
          | member(U,X) )
    | ~ member(ordered_pair(x,y),cross_product(universal_class,universal_class))
    | member(x,universal_class) ),
    inference(quant_inst,[status(thm)],]) ).

tff(20,plain,
    ( ~ ! [V: $i,Y: $i,U: $i,X: $i] :
          ( ~ member(ordered_pair(U,V),cross_product(X,Y))
          | member(U,X) )
    | ~ member(ordered_pair(x,y),cross_product(universal_class,universal_class))
    | member(x,universal_class) ),
    inference(modus_ponens,[status(thm)],[19,18]) ).

tff(21,plain,
    member(x,universal_class),
    inference(unit_resolution,[status(thm)],[20,17,10]) ).

tff(22,plain,
    ^ [Y: $i,X: $i] :
      refl(
        ( ( ~ member(X,universal_class)
          | member(X,unordered_pair(X,Y)) )
      <=> ( ~ member(X,universal_class)
          | member(X,unordered_pair(X,Y)) ) )),
    inference(bind,[status(th)],]) ).

tff(23,plain,
    ( ! [Y: $i,X: $i] :
        ( ~ member(X,universal_class)
        | member(X,unordered_pair(X,Y)) )
  <=> ! [Y: $i,X: $i] :
        ( ~ member(X,universal_class)
        | member(X,unordered_pair(X,Y)) ) ),
    inference(quant_intro,[status(thm)],[22]) ).

tff(24,plain,
    ( ! [Y: $i,X: $i] :
        ( ~ member(X,universal_class)
        | member(X,unordered_pair(X,Y)) )
  <=> ! [Y: $i,X: $i] :
        ( ~ member(X,universal_class)
        | member(X,unordered_pair(X,Y)) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(25,axiom,
    ! [Y: $i,X: $i] :
      ( ~ member(X,universal_class)
      | member(X,unordered_pair(X,Y)) ),
    file('/export/starexec/sandbox2/benchmark/Axioms/SET004-0.ax',unordered_pair2) ).

tff(26,plain,
    ! [Y: $i,X: $i] :
      ( ~ member(X,universal_class)
      | member(X,unordered_pair(X,Y)) ),
    inference(modus_ponens,[status(thm)],[25,24]) ).

tff(27,plain,
    ! [Y: $i,X: $i] :
      ( ~ member(X,universal_class)
      | member(X,unordered_pair(X,Y)) ),
    inference(skolemize,[status(sab)],[26]) ).

tff(28,plain,
    ! [Y: $i,X: $i] :
      ( ~ member(X,universal_class)
      | member(X,unordered_pair(X,Y)) ),
    inference(modus_ponens,[status(thm)],[27,23]) ).

tff(29,plain,
    ( ( ~ ! [Y: $i,X: $i] :
            ( ~ member(X,universal_class)
            | member(X,unordered_pair(X,Y)) )
      | ~ member(x,universal_class)
      | member(x,unordered_pair(x,z)) )
  <=> ( ~ ! [Y: $i,X: $i] :
            ( ~ member(X,universal_class)
            | member(X,unordered_pair(X,Y)) )
      | ~ member(x,universal_class)
      | member(x,unordered_pair(x,z)) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(30,plain,
    ( ~ ! [Y: $i,X: $i] :
          ( ~ member(X,universal_class)
          | member(X,unordered_pair(X,Y)) )
    | ~ member(x,universal_class)
    | member(x,unordered_pair(x,z)) ),
    inference(quant_inst,[status(thm)],]) ).

tff(31,plain,
    ( ~ ! [Y: $i,X: $i] :
          ( ~ member(X,universal_class)
          | member(X,unordered_pair(X,Y)) )
    | ~ member(x,universal_class)
    | member(x,unordered_pair(x,z)) ),
    inference(modus_ponens,[status(thm)],[30,29]) ).

tff(32,plain,
    member(x,unordered_pair(x,z)),
    inference(unit_resolution,[status(thm)],[31,28,21]) ).

tff(33,plain,
    member(x,unordered_pair(y,z)),
    inference(modus_ponens,[status(thm)],[32,7]) ).

tff(34,plain,
    ( ( x != y )
  <=> ( x != y ) ),
    inference(rewrite,[status(thm)],]) ).

tff(35,axiom,
    x != y,
    file('/export/starexec/sandbox2/benchmark/theBenchmark.p',prove_right_cancellation_3) ).

tff(36,plain,
    x != y,
    inference(modus_ponens,[status(thm)],[35,34]) ).

tff(37,plain,
    ^ [Y: $i,U: $i,X: $i] :
      refl(
        ( ( ( U = Y )
          | ( U = X )
          | ~ member(U,unordered_pair(X,Y)) )
      <=> ( ( U = Y )
          | ( U = X )
          | ~ member(U,unordered_pair(X,Y)) ) )),
    inference(bind,[status(th)],]) ).

tff(38,plain,
    ( ! [Y: $i,U: $i,X: $i] :
        ( ( U = Y )
        | ( U = X )
        | ~ member(U,unordered_pair(X,Y)) )
  <=> ! [Y: $i,U: $i,X: $i] :
        ( ( U = Y )
        | ( U = X )
        | ~ member(U,unordered_pair(X,Y)) ) ),
    inference(quant_intro,[status(thm)],[37]) ).

tff(39,plain,
    ( ! [Y: $i,U: $i,X: $i] :
        ( ( U = Y )
        | ( U = X )
        | ~ member(U,unordered_pair(X,Y)) )
  <=> ! [Y: $i,U: $i,X: $i] :
        ( ( U = Y )
        | ( U = X )
        | ~ member(U,unordered_pair(X,Y)) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(40,plain,
    ^ [Y: $i,U: $i,X: $i] :
      rewrite(
        ( ( ~ member(U,unordered_pair(X,Y))
          | ( U = X )
          | ( U = Y ) )
      <=> ( ( U = Y )
          | ( U = X )
          | ~ member(U,unordered_pair(X,Y)) ) )),
    inference(bind,[status(th)],]) ).

tff(41,plain,
    ( ! [Y: $i,U: $i,X: $i] :
        ( ~ member(U,unordered_pair(X,Y))
        | ( U = X )
        | ( U = Y ) )
  <=> ! [Y: $i,U: $i,X: $i] :
        ( ( U = Y )
        | ( U = X )
        | ~ member(U,unordered_pair(X,Y)) ) ),
    inference(quant_intro,[status(thm)],[40]) ).

tff(42,axiom,
    ! [Y: $i,U: $i,X: $i] :
      ( ~ member(U,unordered_pair(X,Y))
      | ( U = X )
      | ( U = Y ) ),
    file('/export/starexec/sandbox2/benchmark/Axioms/SET004-0.ax',unordered_pair_member) ).

tff(43,plain,
    ! [Y: $i,U: $i,X: $i] :
      ( ( U = Y )
      | ( U = X )
      | ~ member(U,unordered_pair(X,Y)) ),
    inference(modus_ponens,[status(thm)],[42,41]) ).

tff(44,plain,
    ! [Y: $i,U: $i,X: $i] :
      ( ( U = Y )
      | ( U = X )
      | ~ member(U,unordered_pair(X,Y)) ),
    inference(modus_ponens,[status(thm)],[43,39]) ).

tff(45,plain,
    ! [Y: $i,U: $i,X: $i] :
      ( ( U = Y )
      | ( U = X )
      | ~ member(U,unordered_pair(X,Y)) ),
    inference(skolemize,[status(sab)],[44]) ).

tff(46,plain,
    ! [Y: $i,U: $i,X: $i] :
      ( ( U = Y )
      | ( U = X )
      | ~ member(U,unordered_pair(X,Y)) ),
    inference(modus_ponens,[status(thm)],[45,38]) ).

tff(47,plain,
    ( ( ~ ! [Y: $i,U: $i,X: $i] :
            ( ( U = Y )
            | ( U = X )
            | ~ member(U,unordered_pair(X,Y)) )
      | ( x = y )
      | ( x = z )
      | ~ member(x,unordered_pair(y,z)) )
  <=> ( ~ ! [Y: $i,U: $i,X: $i] :
            ( ( U = Y )
            | ( U = X )
            | ~ member(U,unordered_pair(X,Y)) )
      | ( x = y )
      | ( x = z )
      | ~ member(x,unordered_pair(y,z)) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(48,plain,
    ( ( ( x = z )
      | ( x = y )
      | ~ member(x,unordered_pair(y,z)) )
  <=> ( ( x = y )
      | ( x = z )
      | ~ member(x,unordered_pair(y,z)) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(49,plain,
    ( ( ~ ! [Y: $i,U: $i,X: $i] :
            ( ( U = Y )
            | ( U = X )
            | ~ member(U,unordered_pair(X,Y)) )
      | ( x = z )
      | ( x = y )
      | ~ member(x,unordered_pair(y,z)) )
  <=> ( ~ ! [Y: $i,U: $i,X: $i] :
            ( ( U = Y )
            | ( U = X )
            | ~ member(U,unordered_pair(X,Y)) )
      | ( x = y )
      | ( x = z )
      | ~ member(x,unordered_pair(y,z)) ) ),
    inference(monotonicity,[status(thm)],[48]) ).

tff(50,plain,
    ( ( ~ ! [Y: $i,U: $i,X: $i] :
            ( ( U = Y )
            | ( U = X )
            | ~ member(U,unordered_pair(X,Y)) )
      | ( x = z )
      | ( x = y )
      | ~ member(x,unordered_pair(y,z)) )
  <=> ( ~ ! [Y: $i,U: $i,X: $i] :
            ( ( U = Y )
            | ( U = X )
            | ~ member(U,unordered_pair(X,Y)) )
      | ( x = y )
      | ( x = z )
      | ~ member(x,unordered_pair(y,z)) ) ),
    inference(transitivity,[status(thm)],[49,47]) ).

tff(51,plain,
    ( ~ ! [Y: $i,U: $i,X: $i] :
          ( ( U = Y )
          | ( U = X )
          | ~ member(U,unordered_pair(X,Y)) )
    | ( x = z )
    | ( x = y )
    | ~ member(x,unordered_pair(y,z)) ),
    inference(quant_inst,[status(thm)],]) ).

tff(52,plain,
    ( ~ ! [Y: $i,U: $i,X: $i] :
          ( ( U = Y )
          | ( U = X )
          | ~ member(U,unordered_pair(X,Y)) )
    | ( x = y )
    | ( x = z )
    | ~ member(x,unordered_pair(y,z)) ),
    inference(modus_ponens,[status(thm)],[51,50]) ).

tff(53,plain,
    ( ( x = z )
    | ~ member(x,unordered_pair(y,z)) ),
    inference(unit_resolution,[status(thm)],[52,46,36]) ).

tff(54,plain,
    x = z,
    inference(unit_resolution,[status(thm)],[53,33]) ).

tff(55,plain,
    z = x,
    inference(symmetry,[status(thm)],[54]) ).

tff(56,plain,
    ( ( y = z )
  <=> ( y = x ) ),
    inference(monotonicity,[status(thm)],[55]) ).

tff(57,plain,
    ( ( y = z )
  <=> ( x = y ) ),
    inference(transitivity,[status(thm)],[56,1]) ).

tff(58,plain,
    ( ( x = y )
  <=> ( y = z ) ),
    inference(symmetry,[status(thm)],[57]) ).

tff(59,plain,
    ( ( x != y )
  <=> ( y != z ) ),
    inference(monotonicity,[status(thm)],[58]) ).

tff(60,plain,
    y != z,
    inference(modus_ponens,[status(thm)],[36,59]) ).

tff(61,plain,
    ( member(y,unordered_pair(x,z))
  <=> member(y,unordered_pair(y,z)) ),
    inference(monotonicity,[status(thm)],[4]) ).

tff(62,plain,
    ( member(y,unordered_pair(y,z))
  <=> member(y,unordered_pair(x,z)) ),
    inference(symmetry,[status(thm)],[61]) ).

tff(63,plain,
    ^ [V: $i,Y: $i,U: $i,X: $i] :
      refl(
        ( ( ~ member(ordered_pair(U,V),cross_product(X,Y))
          | member(V,Y) )
      <=> ( ~ member(ordered_pair(U,V),cross_product(X,Y))
          | member(V,Y) ) )),
    inference(bind,[status(th)],]) ).

tff(64,plain,
    ( ! [V: $i,Y: $i,U: $i,X: $i] :
        ( ~ member(ordered_pair(U,V),cross_product(X,Y))
        | member(V,Y) )
  <=> ! [V: $i,Y: $i,U: $i,X: $i] :
        ( ~ member(ordered_pair(U,V),cross_product(X,Y))
        | member(V,Y) ) ),
    inference(quant_intro,[status(thm)],[63]) ).

tff(65,plain,
    ( ! [V: $i,Y: $i,U: $i,X: $i] :
        ( ~ member(ordered_pair(U,V),cross_product(X,Y))
        | member(V,Y) )
  <=> ! [V: $i,Y: $i,U: $i,X: $i] :
        ( ~ member(ordered_pair(U,V),cross_product(X,Y))
        | member(V,Y) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(66,axiom,
    ! [V: $i,Y: $i,U: $i,X: $i] :
      ( ~ member(ordered_pair(U,V),cross_product(X,Y))
      | member(V,Y) ),
    file('/export/starexec/sandbox2/benchmark/Axioms/SET004-0.ax',cartesian_product2) ).

tff(67,plain,
    ! [V: $i,Y: $i,U: $i,X: $i] :
      ( ~ member(ordered_pair(U,V),cross_product(X,Y))
      | member(V,Y) ),
    inference(modus_ponens,[status(thm)],[66,65]) ).

tff(68,plain,
    ! [V: $i,Y: $i,U: $i,X: $i] :
      ( ~ member(ordered_pair(U,V),cross_product(X,Y))
      | member(V,Y) ),
    inference(skolemize,[status(sab)],[67]) ).

tff(69,plain,
    ! [V: $i,Y: $i,U: $i,X: $i] :
      ( ~ member(ordered_pair(U,V),cross_product(X,Y))
      | member(V,Y) ),
    inference(modus_ponens,[status(thm)],[68,64]) ).

tff(70,plain,
    ( ( ~ ! [V: $i,Y: $i,U: $i,X: $i] :
            ( ~ member(ordered_pair(U,V),cross_product(X,Y))
            | member(V,Y) )
      | ~ member(ordered_pair(x,y),cross_product(universal_class,universal_class))
      | member(y,universal_class) )
  <=> ( ~ ! [V: $i,Y: $i,U: $i,X: $i] :
            ( ~ member(ordered_pair(U,V),cross_product(X,Y))
            | member(V,Y) )
      | ~ member(ordered_pair(x,y),cross_product(universal_class,universal_class))
      | member(y,universal_class) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(71,plain,
    ( ~ ! [V: $i,Y: $i,U: $i,X: $i] :
          ( ~ member(ordered_pair(U,V),cross_product(X,Y))
          | member(V,Y) )
    | ~ member(ordered_pair(x,y),cross_product(universal_class,universal_class))
    | member(y,universal_class) ),
    inference(quant_inst,[status(thm)],]) ).

tff(72,plain,
    ( ~ ! [V: $i,Y: $i,U: $i,X: $i] :
          ( ~ member(ordered_pair(U,V),cross_product(X,Y))
          | member(V,Y) )
    | ~ member(ordered_pair(x,y),cross_product(universal_class,universal_class))
    | member(y,universal_class) ),
    inference(modus_ponens,[status(thm)],[71,70]) ).

tff(73,plain,
    member(y,universal_class),
    inference(unit_resolution,[status(thm)],[72,69,10]) ).

tff(74,plain,
    ( ( ~ ! [Y: $i,X: $i] :
            ( ~ member(X,universal_class)
            | member(X,unordered_pair(X,Y)) )
      | ~ member(y,universal_class)
      | member(y,unordered_pair(y,z)) )
  <=> ( ~ ! [Y: $i,X: $i] :
            ( ~ member(X,universal_class)
            | member(X,unordered_pair(X,Y)) )
      | ~ member(y,universal_class)
      | member(y,unordered_pair(y,z)) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(75,plain,
    ( ~ ! [Y: $i,X: $i] :
          ( ~ member(X,universal_class)
          | member(X,unordered_pair(X,Y)) )
    | ~ member(y,universal_class)
    | member(y,unordered_pair(y,z)) ),
    inference(quant_inst,[status(thm)],]) ).

tff(76,plain,
    ( ~ ! [Y: $i,X: $i] :
          ( ~ member(X,universal_class)
          | member(X,unordered_pair(X,Y)) )
    | ~ member(y,universal_class)
    | member(y,unordered_pair(y,z)) ),
    inference(modus_ponens,[status(thm)],[75,74]) ).

tff(77,plain,
    member(y,unordered_pair(y,z)),
    inference(unit_resolution,[status(thm)],[76,28,73]) ).

tff(78,plain,
    member(y,unordered_pair(x,z)),
    inference(modus_ponens,[status(thm)],[77,62]) ).

tff(79,plain,
    ( ( x = y )
  <=> ( y = x ) ),
    inference(symmetry,[status(thm)],[1]) ).

tff(80,plain,
    ( ( x != y )
  <=> ( y != x ) ),
    inference(monotonicity,[status(thm)],[79]) ).

tff(81,plain,
    y != x,
    inference(modus_ponens,[status(thm)],[36,80]) ).

tff(82,plain,
    ( ( ~ ! [Y: $i,U: $i,X: $i] :
            ( ( U = Y )
            | ( U = X )
            | ~ member(U,unordered_pair(X,Y)) )
      | ( y = z )
      | ( y = x )
      | ~ member(y,unordered_pair(x,z)) )
  <=> ( ~ ! [Y: $i,U: $i,X: $i] :
            ( ( U = Y )
            | ( U = X )
            | ~ member(U,unordered_pair(X,Y)) )
      | ( y = z )
      | ( y = x )
      | ~ member(y,unordered_pair(x,z)) ) ),
    inference(rewrite,[status(thm)],]) ).

tff(83,plain,
    ( ~ ! [Y: $i,U: $i,X: $i] :
          ( ( U = Y )
          | ( U = X )
          | ~ member(U,unordered_pair(X,Y)) )
    | ( y = z )
    | ( y = x )
    | ~ member(y,unordered_pair(x,z)) ),
    inference(quant_inst,[status(thm)],]) ).

tff(84,plain,
    ( ~ ! [Y: $i,U: $i,X: $i] :
          ( ( U = Y )
          | ( U = X )
          | ~ member(U,unordered_pair(X,Y)) )
    | ( y = z )
    | ( y = x )
    | ~ member(y,unordered_pair(x,z)) ),
    inference(modus_ponens,[status(thm)],[83,82]) ).

tff(85,plain,
    ( ( y = z )
    | ( y = x )
    | ~ member(y,unordered_pair(x,z)) ),
    inference(unit_resolution,[status(thm)],[84,46]) ).

tff(86,plain,
    y = z,
    inference(unit_resolution,[status(thm)],[85,81,78]) ).

tff(87,plain,
    $false,
    inference(unit_resolution,[status(thm)],[86,60]) ).

%------------------------------------------------------------------------------
%----ORIGINAL SYSTEM OUTPUT
% 0.03/0.12  % Problem  : SET072-6 : TPTP v8.1.0. Bugfixed v2.1.0.
% 0.03/0.12  % Command  : z3_tptp -proof -model -t:%d -file:%s
% 0.12/0.33  % Computer : n022.cluster.edu
% 0.12/0.33  % Model    : x86_64 x86_64
% 0.12/0.33  % CPU      : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
% 0.12/0.33  % Memory   : 8042.1875MB
% 0.12/0.33  % OS       : Linux 3.10.0-693.el7.x86_64
% 0.12/0.33  % CPULimit : 300
% 0.12/0.33  % WCLimit  : 300
% 0.12/0.33  % DateTime : Sat Sep  3 02:04:24 EDT 2022
% 0.12/0.33  % CPUTime  : 
% 0.12/0.34  Z3tptp [4.8.9.0] (c) 2006-20**. Microsoft Corp.
% 0.12/0.34  Usage: tptp [options] [-file:]file
% 0.12/0.34    -h, -?       prints this message.
% 0.12/0.34    -smt2        print SMT-LIB2 benchmark.
% 0.12/0.34    -m, -model   generate model.
% 0.12/0.34    -p, -proof   generate proof.
% 0.12/0.34    -c, -core    generate unsat core of named formulas.
% 0.12/0.34    -st, -statistics display statistics.
% 0.12/0.34    -t:timeout   set timeout (in second).
% 0.12/0.34    -smt2status  display status in smt2 format instead of SZS.
% 0.12/0.34    -check_status check the status produced by Z3 against annotation in benchmark.
% 0.12/0.34    -<param>:<value> configuration parameter and value.
% 0.12/0.34    -o:<output-file> file to place output in.
% 0.19/0.41  % SZS status Unsatisfiable
% 0.19/0.41  % SZS output start Proof
% See solution above
%------------------------------------------------------------------------------