TSTP Solution File: LCL096-10 by Bliksem---1.12

View Problem - Process Solution

%------------------------------------------------------------------------------
% File     : Bliksem---1.12
% Problem  : LCL096-10 : TPTP v8.1.0. Released v7.3.0.
% Transfm  : none
% Format   : tptp:raw
% Command  : bliksem %s

% Computer : n025.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  : 0s
% DateTime : Sun Jul 17 07:50:16 EDT 2022

% Result   : Unsatisfiable 2.10s 2.49s
% Output   : Refutation 2.10s
% Verified : 
% SZS Type : -

% Comments : 
%------------------------------------------------------------------------------
%----WARNING: Could not form TPTP format derivation
%------------------------------------------------------------------------------
%----ORIGINAL SYSTEM OUTPUT
% 0.07/0.12  % Problem  : LCL096-10 : TPTP v8.1.0. Released v7.3.0.
% 0.07/0.13  % Command  : bliksem %s
% 0.13/0.34  % Computer : n025.cluster.edu
% 0.13/0.34  % Model    : x86_64 x86_64
% 0.13/0.34  % CPU      : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
% 0.13/0.34  % Memory   : 8042.1875MB
% 0.13/0.34  % OS       : Linux 3.10.0-693.el7.x86_64
% 0.13/0.34  % CPULimit : 300
% 0.13/0.34  % DateTime : Mon Jul  4 05:14:56 EDT 2022
% 0.13/0.34  % CPUTime  : 
% 2.10/2.49  *** allocated 10000 integers for termspace/termends
% 2.10/2.49  *** allocated 10000 integers for clauses
% 2.10/2.49  *** allocated 10000 integers for justifications
% 2.10/2.49  Bliksem 1.12
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  Automatic Strategy Selection
% 2.10/2.49  
% 2.10/2.49  Clauses:
% 2.10/2.49  [
% 2.10/2.49     [ =( ifeq( X, X, Y, Z ), Y ) ],
% 2.10/2.49     [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49    ,
% 2.10/2.49     [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), T ), T )
% 2.10/2.49     ), true ) ],
% 2.10/2.49     [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( 
% 2.10/2.49    equivalent( Y, Z ), T ) ), U ), U ) ), true ) ],
% 2.10/2.49     [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( equivalent( X, 
% 2.10/2.49    Y ), Z ), T ), equivalent( equivalent( equivalent( X, U ), Z ), 
% 2.10/2.49    equivalent( equivalent( Y, U ), T ) ) ) ), true ) ],
% 2.10/2.49     [ ~( =( 'is_a_theorem'( equivalent( equivalent( equivalent( a, 
% 2.10/2.49    equivalent( equivalent( b, b ), a ) ), c ), c ) ), true ) ) ]
% 2.10/2.49  ] .
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  percentage equality = 1.000000, percentage horn = 1.000000
% 2.10/2.49  This is a pure equality problem
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  Options Used:
% 2.10/2.49  
% 2.10/2.49  useres =            1
% 2.10/2.49  useparamod =        1
% 2.10/2.49  useeqrefl =         1
% 2.10/2.49  useeqfact =         1
% 2.10/2.49  usefactor =         1
% 2.10/2.49  usesimpsplitting =  0
% 2.10/2.49  usesimpdemod =      5
% 2.10/2.49  usesimpres =        3
% 2.10/2.49  
% 2.10/2.49  resimpinuse      =  1000
% 2.10/2.49  resimpclauses =     20000
% 2.10/2.49  substype =          eqrewr
% 2.10/2.49  backwardsubs =      1
% 2.10/2.49  selectoldest =      5
% 2.10/2.49  
% 2.10/2.49  litorderings [0] =  split
% 2.10/2.49  litorderings [1] =  extend the termordering, first sorting on arguments
% 2.10/2.49  
% 2.10/2.49  termordering =      kbo
% 2.10/2.49  
% 2.10/2.49  litapriori =        0
% 2.10/2.49  termapriori =       1
% 2.10/2.49  litaposteriori =    0
% 2.10/2.49  termaposteriori =   0
% 2.10/2.49  demodaposteriori =  0
% 2.10/2.49  ordereqreflfact =   0
% 2.10/2.49  
% 2.10/2.49  litselect =         negord
% 2.10/2.49  
% 2.10/2.49  maxweight =         15
% 2.10/2.49  maxdepth =          30000
% 2.10/2.49  maxlength =         115
% 2.10/2.49  maxnrvars =         195
% 2.10/2.49  excuselevel =       1
% 2.10/2.49  increasemaxweight = 1
% 2.10/2.49  
% 2.10/2.49  maxselected =       10000000
% 2.10/2.49  maxnrclauses =      10000000
% 2.10/2.49  
% 2.10/2.49  showgenerated =    0
% 2.10/2.49  showkept =         0
% 2.10/2.49  showselected =     0
% 2.10/2.49  showdeleted =      0
% 2.10/2.49  showresimp =       1
% 2.10/2.49  showstatus =       2000
% 2.10/2.49  
% 2.10/2.49  prologoutput =     1
% 2.10/2.49  nrgoals =          5000000
% 2.10/2.49  totalproof =       1
% 2.10/2.49  
% 2.10/2.49  Symbols occurring in the translation:
% 2.10/2.49  
% 2.10/2.49  {}  [0, 0]      (w:1, o:2, a:1, s:1, b:0), 
% 2.10/2.49  .  [1, 2]      (w:1, o:27, a:1, s:1, b:0), 
% 2.10/2.49  !  [4, 1]      (w:0, o:21, a:1, s:1, b:0), 
% 2.10/2.49  =  [13, 2]      (w:1, o:0, a:0, s:1, b:0), 
% 2.10/2.49  ==>  [14, 2]      (w:1, o:0, a:0, s:1, b:0), 
% 2.10/2.49  ifeq  [42, 4]      (w:1, o:53, a:1, s:1, b:0), 
% 2.10/2.49  equivalent  [45, 2]      (w:1, o:52, a:1, s:1, b:0), 
% 2.10/2.49  'is_a_theorem'  [46, 1]      (w:1, o:26, a:1, s:1, b:0), 
% 2.10/2.49  true  [47, 0]      (w:1, o:14, a:1, s:1, b:0), 
% 2.10/2.49  a  [51, 0]      (w:1, o:18, a:1, s:1, b:0), 
% 2.10/2.49  b  [52, 0]      (w:1, o:19, a:1, s:1, b:0), 
% 2.10/2.49  c  [53, 0]      (w:1, o:20, a:1, s:1, b:0).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  Starting Search:
% 2.10/2.49  
% 2.10/2.49  Resimplifying inuse:
% 2.10/2.49  Done
% 2.10/2.49  
% 2.10/2.49  Failed to find proof!
% 2.10/2.49  maxweight =   15
% 2.10/2.49  maxnrclauses = 10000000
% 2.10/2.49  Generated: 270
% 2.10/2.49  Kept: 25
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  The strategy used was not complete!
% 2.10/2.49  
% 2.10/2.49  Increased maxweight to 16
% 2.10/2.49  
% 2.10/2.49  Starting Search:
% 2.10/2.49  
% 2.10/2.49  Resimplifying inuse:
% 2.10/2.49  Done
% 2.10/2.49  
% 2.10/2.49  Failed to find proof!
% 2.10/2.49  maxweight =   16
% 2.10/2.49  maxnrclauses = 10000000
% 2.10/2.49  Generated: 270
% 2.10/2.49  Kept: 25
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  The strategy used was not complete!
% 2.10/2.49  
% 2.10/2.49  Increased maxweight to 17
% 2.10/2.49  
% 2.10/2.49  Starting Search:
% 2.10/2.49  
% 2.10/2.49  Resimplifying inuse:
% 2.10/2.49  Done
% 2.10/2.49  
% 2.10/2.49  Failed to find proof!
% 2.10/2.49  maxweight =   17
% 2.10/2.49  maxnrclauses = 10000000
% 2.10/2.49  Generated: 459
% 2.10/2.49  Kept: 33
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  The strategy used was not complete!
% 2.10/2.49  
% 2.10/2.49  Increased maxweight to 18
% 2.10/2.49  
% 2.10/2.49  Starting Search:
% 2.10/2.49  
% 2.10/2.49  Resimplifying inuse:
% 2.10/2.49  Done
% 2.10/2.49  
% 2.10/2.49  Failed to find proof!
% 2.10/2.49  maxweight =   18
% 2.10/2.49  maxnrclauses = 10000000
% 2.10/2.49  Generated: 13111
% 2.10/2.49  Kept: 187
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  The strategy used was not complete!
% 2.10/2.49  
% 2.10/2.49  Increased maxweight to 19
% 2.10/2.49  
% 2.10/2.49  Starting Search:
% 2.10/2.49  
% 2.10/2.49  Resimplifying inuse:
% 2.10/2.49  Done
% 2.10/2.49  
% 2.10/2.49  Failed to find proof!
% 2.10/2.49  maxweight =   19
% 2.10/2.49  maxnrclauses = 10000000
% 2.10/2.49  Generated: 13111
% 2.10/2.49  Kept: 187
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  The strategy used was not complete!
% 2.10/2.49  
% 2.10/2.49  Increased maxweight to 20
% 2.10/2.49  
% 2.10/2.49  Starting Search:
% 2.10/2.49  
% 2.10/2.49  Resimplifying inuse:
% 2.10/2.49  Done
% 2.10/2.49  
% 2.10/2.49  Failed to find proof!
% 2.10/2.49  maxweight =   20
% 2.10/2.49  maxnrclauses = 10000000
% 2.10/2.49  Generated: 13111
% 2.10/2.49  Kept: 187
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  The strategy used was not complete!
% 2.10/2.49  
% 2.10/2.49  Increased maxweight to 21
% 2.10/2.49  
% 2.10/2.49  Starting Search:
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  Bliksems!, er is een bewijs:
% 2.10/2.49  % SZS status Unsatisfiable
% 2.10/2.49  % SZS output start Refutation
% 2.10/2.49  
% 2.10/2.49  clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  .
% 2.10/2.49  clause( 2, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ), T ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 3, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ), U ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 4, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), Z ), T ), equivalent( equivalent( equivalent( X, U )
% 2.10/2.49    , Z ), equivalent( equivalent( Y, U ), T ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 5, [ ~( =( 'is_a_theorem'( equivalent( equivalent( equivalent( a, 
% 2.10/2.49    equivalent( equivalent( b, b ), a ) ), c ), c ) ), true ) ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 6, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), T ) ), 
% 2.10/2.49    true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 7, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.49    equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), true )
% 2.10/2.49    , true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 9, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( 
% 2.10/2.49    equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), true ), true
% 2.10/2.49     ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 12, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, T )
% 2.10/2.49    , equivalent( X, Z ) ), equivalent( equivalent( Y, T ), equivalent( Y, Z
% 2.10/2.49     ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 16, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( T, 
% 2.10/2.49    Y ), equivalent( T, Z ) ) ), true ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 17, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( X, 
% 2.10/2.49    Z ) ), equivalent( T, equivalent( X, Z ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 18, [ =( 'is_a_theorem'( equivalent( equivalent( U, T ), equivalent( 
% 2.10/2.49    U, equivalent( equivalent( Y, Y ), T ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 19, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y )
% 2.10/2.49    , equivalent( X, Z ) ), equivalent( Y, Z ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 22, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Z ), equivalent( 
% 2.10/2.49    Y, Z ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 26, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), true
% 2.10/2.49     ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 28, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ), 
% 2.10/2.49    true ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 30, [ =( 'is_a_theorem'( equivalent( Y, equivalent( equivalent( Z, 
% 2.10/2.49    Z ), Y ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 31, [ =( 'is_a_theorem'( equivalent( Y, Y ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 36, [ =( ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( Y, Y ), X ) ), true ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 39, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( equivalent( Y
% 2.10/2.49    , Z ), T ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 40, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Z )
% 2.10/2.49    , T ), equivalent( equivalent( Y, Z ), equivalent( equivalent( X, Y ), T
% 2.10/2.49     ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 43, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Y ), equivalent( 
% 2.10/2.49    X, X ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 45, [ =( 'is_a_theorem'( equivalent( equivalent( Z, Z ), equivalent( 
% 2.10/2.49    equivalent( X, X ), equivalent( Y, Y ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 51, [ =( 'is_a_theorem'( equivalent( equivalent( Z, equivalent( X, 
% 2.10/2.49    X ) ), equivalent( Z, equivalent( Y, Y ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 54, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), 
% 2.10/2.49    equivalent( T, T ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 101, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Z ), 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 104, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( equivalent( T, T ), equivalent( equivalent( Z, X ), 
% 2.10/2.49    equivalent( Z, Y ) ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 106, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ) ), equivalent( T, equivalent( Y
% 2.10/2.49    , Z ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 107, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ), 
% 2.10/2.49    true ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 112, [ =( 'is_a_theorem'( equivalent( Y, equivalent( equivalent( Z
% 2.10/2.49    , equivalent( X, X ) ), equivalent( Z, Y ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 118, [ =( 'is_a_theorem'( equivalent( Z, equivalent( X, equivalent( 
% 2.10/2.49    equivalent( X, equivalent( Y, Y ) ), Z ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 129, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.49    equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ), 
% 2.10/2.49    T ) ), true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 138, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( Y, Z
% 2.10/2.49     ), T ), equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) )
% 2.10/2.49    , T ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 152, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( X
% 2.10/2.49    , Z ) ), equivalent( equivalent( equivalent( X, Y ), T ), equivalent( Y, 
% 2.10/2.49    Z ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 230, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.49    equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 'is_a_theorem'( 
% 2.10/2.49    equivalent( X, equivalent( Z, T ) ) ), true ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 345, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( Y, T
% 2.10/2.49     ), X ), equivalent( T, equivalent( equivalent( Y, equivalent( Z, Z ) ), 
% 2.10/2.49    X ) ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 367, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( equivalent( Z, X ), T ) ), equivalent( equivalent( Z, Y )
% 2.10/2.49    , T ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 376, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.49    equivalent( X, X ), Z ) ), equivalent( T, Z ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 454, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.49    equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( equivalent( X, Z ) ), 
% 2.10/2.49    true ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 489, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( equivalent( Y, X ), Z ) ), Z ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 522, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( equivalent( Y, X ), Z ) ) ), equivalent( 
% 2.10/2.49    T, Z ) ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 641, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.49    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( X, T ) ), true ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 818, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.49    equivalent( equivalent( Y, Y ), X ) ), Z ), Z ) ), true ) ] )
% 2.10/2.49  .
% 2.10/2.49  clause( 820, [] )
% 2.10/2.49  .
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  % SZS output end Refutation
% 2.10/2.49  found a proof!
% 2.10/2.49  
% 2.10/2.49  % ABCDEFGHIJKLMNOPQRSTUVWXYZ
% 2.10/2.49  
% 2.10/2.49  initialclauses(
% 2.10/2.49  [ clause( 822, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , clause( 823, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  , clause( 824, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ), T ) ), true ) ] )
% 2.10/2.49  , clause( 825, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ), U ) ), true ) ] )
% 2.10/2.49  , clause( 826, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), Z ), T ), equivalent( equivalent( equivalent( X, U )
% 2.10/2.49    , Z ), equivalent( equivalent( Y, U ), T ) ) ) ), true ) ] )
% 2.10/2.49  , clause( 827, [ ~( =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    a, equivalent( equivalent( b, b ), a ) ), c ), c ) ), true ) ) ] )
% 2.10/2.49  ] ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , clause( 822, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  , clause( 823, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y )] ), permutation( 0, [ ==>( 0, 0
% 2.10/2.49     )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 2, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ), T ) ), true ) ] )
% 2.10/2.49  , clause( 824, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ), T ) ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 3, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ), U ) ), true ) ] )
% 2.10/2.49  , clause( 825, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ), U ) ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), :=( U
% 2.10/2.49    , U )] ), permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 4, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), Z ), T ), equivalent( equivalent( equivalent( X, U )
% 2.10/2.49    , Z ), equivalent( equivalent( Y, U ), T ) ) ) ), true ) ] )
% 2.10/2.49  , clause( 826, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), Z ), T ), equivalent( equivalent( equivalent( X, U )
% 2.10/2.49    , Z ), equivalent( equivalent( Y, U ), T ) ) ) ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), :=( U
% 2.10/2.49    , U )] ), permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 5, [ ~( =( 'is_a_theorem'( equivalent( equivalent( equivalent( a, 
% 2.10/2.49    equivalent( equivalent( b, b ), a ) ), c ), c ) ), true ) ) ] )
% 2.10/2.49  , clause( 827, [ ~( =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    a, equivalent( equivalent( b, b ), a ) ), c ), c ) ), true ) ) ] )
% 2.10/2.49  , substitution( 0, [] ), permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 850, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.49     )
% 2.10/2.49  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 852, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.49    equivalent( Y, Z ) ), T ) ), true, 'is_a_theorem'( T ), true ), true ) )
% 2.10/2.49     ] )
% 2.10/2.49  , clause( 2, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ), T ) ), true ) ] )
% 2.10/2.49  , 0, clause( 850, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.49    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.49     ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.49    , substitution( 1, [ :=( X, equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), T ) ), 
% 2.10/2.49    :=( Y, T )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 857, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 852, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), equivalent( Y, Z ) ), T ) ), true, 'is_a_theorem'( T ), true ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), equivalent( Y, Z ) ), T ) ), true, 'is_a_theorem'( T ), true ) ), 
% 2.10/2.49    :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), 
% 2.10/2.49    :=( T, T )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 858, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), T ) ), 
% 2.10/2.49    true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.49  , clause( 857, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.49    ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 6, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), T ) ), 
% 2.10/2.49    true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.49  , clause( 858, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ) ), true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 860, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.49     )
% 2.10/2.49  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 863, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), equivalent( Y, Z ) ), T ), T ), U ) ), true, ifeq( true, true, 
% 2.10/2.49    'is_a_theorem'( U ), true ), true ) ) ] )
% 2.10/2.49  , clause( 2, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ), T ) ), true ) ] )
% 2.10/2.49  , 0, clause( 860, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.49    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.49     ) ) ] )
% 2.10/2.49  , 0, 23, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.49    , substitution( 1, [ :=( X, equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ), T ) ), :=( Y, U )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 865, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 863, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), equivalent( Y, Z ) ), T ), T ), U ) ), true, ifeq( true, true, 
% 2.10/2.49    'is_a_theorem'( U ), true ), true ) ) ] )
% 2.10/2.49  , 0, 22, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( U ) ), 
% 2.10/2.49    :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), 
% 2.10/2.49    :=( T, T ), :=( U, U )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 866, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.49    equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), true )
% 2.10/2.49    , true ) ] )
% 2.10/2.49  , clause( 865, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), 
% 2.10/2.49    :=( U, U )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 7, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.49    equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), true )
% 2.10/2.49    , true ) ] )
% 2.10/2.49  , clause( 866, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.49    true ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), :=( U
% 2.10/2.49    , U )] ), permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 868, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.49     )
% 2.10/2.49  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 870, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), T ), equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 
% 2.10/2.49    'is_a_theorem'( U ), true ), true ) ) ] )
% 2.10/2.49  , clause( 3, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ), U ) ), true ) ] )
% 2.10/2.49  , 0, clause( 868, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.49    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.49     ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), 
% 2.10/2.49    :=( U, U )] ), substitution( 1, [ :=( X, equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ) ), :=( Y, U )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 875, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 870, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ), T ), equivalent( equivalent( Y, Z ), T ) ), U ) ), 
% 2.10/2.49    true, 'is_a_theorem'( U ), true ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ), T ), equivalent( equivalent( Y, Z ), T ) ), U ) ), 
% 2.10/2.49    true, 'is_a_theorem'( U ), true ) ), :=( Z, true )] ), substitution( 1, [
% 2.10/2.49     :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), :=( U, U )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 876, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( 
% 2.10/2.49    equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), true ), true
% 2.10/2.49     ) ] )
% 2.10/2.49  , clause( 875, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), 
% 2.10/2.49    :=( U, U )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 9, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( 
% 2.10/2.49    equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), true ), true
% 2.10/2.49     ) ] )
% 2.10/2.49  , clause( 876, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.49    true ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), :=( U
% 2.10/2.49    , U )] ), permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 878, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.49  , clause( 6, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), T ) ), 
% 2.10/2.49    true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.49    ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 880, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, T ), equivalent( X, Z ) ), equivalent( 
% 2.10/2.49    equivalent( Y, T ), equivalent( Y, Z ) ) ) ), true ) ) ] )
% 2.10/2.49  , clause( 4, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), Z ), T ), equivalent( equivalent( equivalent( X, U )
% 2.10/2.49    , Z ), equivalent( equivalent( Y, U ), T ) ) ) ), true ) ] )
% 2.10/2.49  , 0, clause( 878, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, equivalent( X, Z
% 2.10/2.49     ) ), :=( T, equivalent( Y, Z ) ), :=( U, T )] ), substitution( 1, [ :=( 
% 2.10/2.49    X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, equivalent( equivalent( equivalent( 
% 2.10/2.49    X, T ), equivalent( X, Z ) ), equivalent( equivalent( Y, T ), equivalent( 
% 2.10/2.49    Y, Z ) ) ) )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 882, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    X, Y ), equivalent( X, Z ) ), equivalent( equivalent( T, Y ), equivalent( 
% 2.10/2.49    T, Z ) ) ) ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 880, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, T ), equivalent( X, Z ) ), equivalent( 
% 2.10/2.49    equivalent( Y, T ), equivalent( Y, Z ) ) ) ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( 
% 2.10/2.49    equivalent( T, Y ), equivalent( T, Z ) ) ) ) ), :=( Z, true )] ), 
% 2.10/2.49    substitution( 1, [ :=( X, X ), :=( Y, T ), :=( Z, Z ), :=( T, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 883, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( X, Z ) ), equivalent( equivalent( T, Y ), equivalent( T, 
% 2.10/2.49    Z ) ) ) ), true ) ] )
% 2.10/2.49  , clause( 882, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( equivalent( T, Y )
% 2.10/2.49    , equivalent( T, Z ) ) ) ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.49    ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 12, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, T )
% 2.10/2.49    , equivalent( X, Z ) ), equivalent( equivalent( Y, T ), equivalent( Y, Z
% 2.10/2.49     ) ) ) ), true ) ] )
% 2.10/2.49  , clause( 883, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.49    Y ), equivalent( X, Z ) ), equivalent( equivalent( T, Y ), equivalent( T
% 2.10/2.49    , Z ) ) ) ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, T ), :=( Z, Z ), :=( T, Y )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 885, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.49     )
% 2.10/2.49  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 887, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( T, Y ), equivalent( T, Z ) ) ), true ), true ) )
% 2.10/2.49     ] )
% 2.10/2.49  , clause( 12, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, T
% 2.10/2.49     ), equivalent( X, Z ) ), equivalent( equivalent( Y, T ), equivalent( Y, 
% 2.10/2.49    Z ) ) ) ), true ) ] )
% 2.10/2.49  , 0, clause( 885, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.49    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.49     ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, T ), :=( Z, Z ), :=( T, Y )] )
% 2.10/2.49    , substitution( 1, [ :=( X, equivalent( equivalent( X, Y ), equivalent( X
% 2.10/2.49    , Z ) ) ), :=( Y, equivalent( equivalent( T, Y ), equivalent( T, Z ) ) )] )
% 2.10/2.49    ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 892, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 887, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( equivalent( T, Y ), equivalent( T, Z ) ) ), 
% 2.10/2.49    true ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( equivalent( T, Y ), equivalent( T, Z ) ) ), 
% 2.10/2.49    true ) ), :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), 
% 2.10/2.49    :=( Z, Z ), :=( T, T )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 893, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( T, 
% 2.10/2.49    Y ), equivalent( T, Z ) ) ), true ), true ) ] )
% 2.10/2.49  , clause( 892, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.49    Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.49    ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 16, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( T, 
% 2.10/2.49    Y ), equivalent( T, Z ) ) ), true ), true ) ] )
% 2.10/2.49  , clause( 893, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( T, 
% 2.10/2.49    Y ), equivalent( T, Z ) ) ), true ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 895, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.49  , clause( 16, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( T, 
% 2.10/2.49    Y ), equivalent( T, Z ) ) ), true ), true ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.49    ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 897, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( T, equivalent( X, Z ) ), equivalent( T, equivalent( X, Z ) )
% 2.10/2.49     ) ), true ) ) ] )
% 2.10/2.49  , clause( 12, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, T
% 2.10/2.49     ), equivalent( X, Z ) ), equivalent( equivalent( Y, T ), equivalent( Y, 
% 2.10/2.49    Z ) ) ) ), true ) ] )
% 2.10/2.49  , 0, clause( 895, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, X ), :=( Z, Z ), :=( T, Y )] )
% 2.10/2.49    , substitution( 1, [ :=( X, equivalent( X, Y ) ), :=( Y, equivalent( X, Z
% 2.10/2.49     ) ), :=( Z, equivalent( X, Z ) ), :=( T, T )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 899, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.49    equivalent( Y, Z ) ), equivalent( X, equivalent( Y, Z ) ) ) ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 897, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( T, equivalent( X, Z ) ), equivalent( T, equivalent( X, Z ) )
% 2.10/2.49     ) ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( X, equivalent( Y, Z ) ), equivalent( X, equivalent( Y, Z ) )
% 2.10/2.49     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, Y ), :=( Y, T ), :=( 
% 2.10/2.49    Z, Z ), :=( T, X )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 900, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( Y
% 2.10/2.49    , Z ) ), equivalent( X, equivalent( Y, Z ) ) ) ), true ) ] )
% 2.10/2.49  , clause( 899, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.49    equivalent( Y, Z ) ), equivalent( X, equivalent( Y, Z ) ) ) ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 17, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( X, 
% 2.10/2.49    Z ) ), equivalent( T, equivalent( X, Z ) ) ) ), true ) ] )
% 2.10/2.49  , clause( 900, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( 
% 2.10/2.49    Y, Z ) ), equivalent( X, equivalent( Y, Z ) ) ) ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, T ), :=( Y, X ), :=( Z, Z )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 902, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.49  , clause( 16, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( T, 
% 2.10/2.49    Y ), equivalent( T, Z ) ) ), true ), true ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.49    ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 904, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( U, T ), equivalent( U, equivalent( equivalent( Y, Y ), T ) )
% 2.10/2.49     ) ), true ) ) ] )
% 2.10/2.49  , clause( 4, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), Z ), T ), equivalent( equivalent( equivalent( X, U )
% 2.10/2.49    , Z ), equivalent( equivalent( Y, U ), T ) ) ) ), true ) ] )
% 2.10/2.49  , 0, clause( 902, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), 
% 2.10/2.49    :=( U, Y )] ), substitution( 1, [ :=( X, equivalent( equivalent( X, Y ), 
% 2.10/2.49    Z ) ), :=( Y, T ), :=( Z, equivalent( equivalent( Y, Y ), T ) ), :=( T, U
% 2.10/2.49     )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 906, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ) ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 904, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( U, T ), equivalent( U, equivalent( equivalent( Y, Y ), T ) )
% 2.10/2.49     ) ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, equivalent( equivalent( Z, Z ), Y ) )
% 2.10/2.49     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, T ), :=( Y, Z ), :=( 
% 2.10/2.49    Z, U ), :=( T, Y ), :=( U, X )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 907, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ) ), true ) ] )
% 2.10/2.49  , clause( 906, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ) ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 18, [ =( 'is_a_theorem'( equivalent( equivalent( U, T ), equivalent( 
% 2.10/2.49    U, equivalent( equivalent( Y, Y ), T ) ) ) ), true ) ] )
% 2.10/2.49  , clause( 907, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ) ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, U ), :=( Y, T ), :=( Z, Y )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 909, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.49  , clause( 6, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), T ) ), 
% 2.10/2.49    true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.49    ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 911, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ) ), true ) ) ] )
% 2.10/2.49  , clause( 17, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( X
% 2.10/2.49    , Z ) ), equivalent( T, equivalent( X, Z ) ) ) ), true ) ] )
% 2.10/2.49  , 0, clause( 909, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, Y ), :=( Y, T ), :=( Z, Z ), :=( T, 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) )] ), substitution( 
% 2.10/2.49    1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ) )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 913, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ) ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 911, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ) ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.49     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( 
% 2.10/2.49    Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 914, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( X, Z ) ), equivalent( Y, Z ) ) ), true ) ] )
% 2.10/2.49  , clause( 913, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ) ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 19, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y )
% 2.10/2.49    , equivalent( X, Z ) ), equivalent( Y, Z ) ) ), true ) ] )
% 2.10/2.49  , clause( 914, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.49    Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ) ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 916, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , clause( 7, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.49    equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), true )
% 2.10/2.49    , true ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), 
% 2.10/2.49    :=( U, U )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 918, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( Y, Z ), equivalent( Y, Z ) ) ), true ) ) ] )
% 2.10/2.49  , clause( 3, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.49    equivalent( equivalent( Y, Z ), T ) ), U ), U ) ), true ) ] )
% 2.10/2.49  , 0, clause( 916, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.49     ) ), equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, 
% 2.10/2.49    equivalent( Y, Z ) ), :=( U, equivalent( equivalent( Y, Z ), equivalent( 
% 2.10/2.49    Y, Z ) ) )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), 
% 2.10/2.49    :=( T, equivalent( equivalent( Y, Z ), equivalent( Y, Z ) ) ), :=( U, 
% 2.10/2.49    equivalent( equivalent( Y, Z ), equivalent( Y, Z ) ) )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 920, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Y ) ) ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 918, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( Y, Z ), equivalent( Y, Z ) ) ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Y ) ) ) ), :=( Z, true )] ), 
% 2.10/2.49    substitution( 1, [ :=( X, Z ), :=( Y, X ), :=( Z, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 921, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Y ) ) ), true ) ] )
% 2.10/2.49  , clause( 920, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Y ) ) ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 22, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Z ), equivalent( 
% 2.10/2.49    Y, Z ) ) ), true ) ] )
% 2.10/2.49  , clause( 921, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Y ) ) ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, Y ), :=( Y, Z )] ), permutation( 0, [ ==>( 0, 0
% 2.10/2.49     )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 923, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.49     )
% 2.10/2.49  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 925, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( equivalent( 
% 2.10/2.49    equivalent( X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( 
% 2.10/2.49    equivalent( Y, Z ) ), true ), true ) ) ] )
% 2.10/2.49  , clause( 19, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( X, Z ) ), equivalent( Y, Z ) ) ), true ) ] )
% 2.10/2.49  , 0, clause( 923, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.49    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.49     ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.49    substitution( 1, [ :=( X, equivalent( equivalent( X, Y ), equivalent( X, 
% 2.10/2.49    Z ) ) ), :=( Y, equivalent( Y, Z ) )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 930, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 925, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( Y, Z ) ), true ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( Y, Z ) ), true ) ), :=( Z, true )] ), 
% 2.10/2.49    substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 931, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), true
% 2.10/2.49     ), true ) ] )
% 2.10/2.49  , clause( 930, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.49    Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 26, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), true
% 2.10/2.49     ), true ) ] )
% 2.10/2.49  , clause( 931, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), true
% 2.10/2.49     ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 933, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.49     )
% 2.10/2.49  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.49    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.49     )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 935, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( equivalent( 
% 2.10/2.49    X, Y ) ), true, 'is_a_theorem'( equivalent( X, equivalent( equivalent( Z
% 2.10/2.49    , Z ), Y ) ) ), true ), true ) ) ] )
% 2.10/2.49  , clause( 18, [ =( 'is_a_theorem'( equivalent( equivalent( U, T ), 
% 2.10/2.49    equivalent( U, equivalent( equivalent( Y, Y ), T ) ) ) ), true ) ] )
% 2.10/2.49  , 0, clause( 933, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.49    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.49     ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, T ), :=( Y, Z ), :=( Z, U ), :=( T, Y ), 
% 2.10/2.49    :=( U, X )] ), substitution( 1, [ :=( X, equivalent( X, Y ) ), :=( Y, 
% 2.10/2.49    equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 940, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 935, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( X, Y ) ), true, 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.49    equivalent( Z, Z ), Y ) ) ), true ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( 
% 2.10/2.49    equivalent( X, Y ) ), true, 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.49    equivalent( Z, Z ), Y ) ) ), true ) ), :=( Z, true )] ), substitution( 1
% 2.10/2.49    , [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 941, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ), 
% 2.10/2.49    true ), true ) ] )
% 2.10/2.49  , clause( 940, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true
% 2.10/2.49    , 'is_a_theorem'( equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) )
% 2.10/2.49    , true ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 28, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ), 
% 2.10/2.49    true ), true ) ] )
% 2.10/2.49  , clause( 941, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.49    'is_a_theorem'( equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ), 
% 2.10/2.49    true ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.49    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 943, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , clause( 26, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), true
% 2.10/2.49     ), true ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 945, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( Y, 
% 2.10/2.49    equivalent( equivalent( Z, Z ), Y ) ) ), true ) ) ] )
% 2.10/2.49  , clause( 18, [ =( 'is_a_theorem'( equivalent( equivalent( U, T ), 
% 2.10/2.49    equivalent( U, equivalent( equivalent( Y, Y ), T ) ) ) ), true ) ] )
% 2.10/2.49  , 0, clause( 943, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z )
% 2.10/2.49     ), true ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, T ), :=( Y, Z ), :=( Z, U ), :=( T, Y ), 
% 2.10/2.49    :=( U, X )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, 
% 2.10/2.49    equivalent( equivalent( Z, Z ), Y ) )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 947, [ =( true, 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.49    equivalent( Y, Y ), X ) ) ) ) ] )
% 2.10/2.49  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.49  , 0, clause( 945, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.49    Y, equivalent( equivalent( Z, Z ), Y ) ) ), true ) ) ] )
% 2.10/2.49  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.49    X, equivalent( equivalent( Y, Y ), X ) ) ) ), :=( Z, true )] ), 
% 2.10/2.49    substitution( 1, [ :=( X, Z ), :=( Y, X ), :=( Z, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 948, [ =( 'is_a_theorem'( equivalent( X, equivalent( equivalent( Y
% 2.10/2.49    , Y ), X ) ) ), true ) ] )
% 2.10/2.49  , clause( 947, [ =( true, 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.49    equivalent( Y, Y ), X ) ) ) ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  subsumption(
% 2.10/2.49  clause( 30, [ =( 'is_a_theorem'( equivalent( Y, equivalent( equivalent( Z, 
% 2.10/2.49    Z ), Y ) ) ), true ) ] )
% 2.10/2.49  , clause( 948, [ =( 'is_a_theorem'( equivalent( X, equivalent( equivalent( 
% 2.10/2.49    Y, Y ), X ) ) ), true ) ] )
% 2.10/2.49  , substitution( 0, [ :=( X, Y ), :=( Y, Z )] ), permutation( 0, [ ==>( 0, 0
% 2.10/2.49     )] ) ).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  eqswap(
% 2.10/2.49  clause( 950, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.49     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), 
% 2.10/2.49    true ) ) ] )
% 2.10/2.49  , clause( 26, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.49    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), true
% 2.10/2.49     ), true ) ] )
% 2.10/2.49  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.49  
% 2.10/2.49  
% 2.10/2.49  paramod(
% 2.10/2.49  clause( 952, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( Y, Y
% 2.10/2.49     ) ), true ) ) ] )
% 2.10/2.49  , clause( 22, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Z ), 
% 2.10/2.49    equivalent( Y, Z ) ) ), true ) ] )
% 2.10/2.49  , 0, clause( 950, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.49    X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z )
% 2.10/2.49     ), true ) ) ] )
% 2.10/2.49  , 0, 3, substitution( 0, [ :=( X, Z ), :=( Y, X ), :=( Z, Y )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 956, [ =( true, 'is_a_theorem'( equivalent( X, X ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 952, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    Y, Y ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    X, X ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, Y ), :=( Y, X )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 957, [ =( 'is_a_theorem'( equivalent( X, X ) ), true ) ] )
% 2.10/2.50  , clause( 956, [ =( true, 'is_a_theorem'( equivalent( X, X ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 31, [ =( 'is_a_theorem'( equivalent( Y, Y ) ), true ) ] )
% 2.10/2.50  , clause( 957, [ =( 'is_a_theorem'( equivalent( X, X ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, Y )] ), permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 959, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.50     )
% 2.10/2.50  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.50    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.50     )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 961, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( X ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( equivalent( Y, Y ), X ) ), true ), true ) ) ]
% 2.10/2.50     )
% 2.10/2.50  , clause( 30, [ =( 'is_a_theorem'( equivalent( Y, equivalent( equivalent( Z
% 2.10/2.50    , Z ), Y ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 959, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.50    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.50     ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Z ), :=( Y, X ), :=( Z, Y )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, X ), :=( Y, equivalent( equivalent( Y, Y ), X )
% 2.10/2.50     )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 966, [ =( true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), true ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 961, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( X ), 
% 2.10/2.50    true, 'is_a_theorem'( equivalent( equivalent( Y, Y ), X ) ), true ), true
% 2.10/2.50     ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( X )
% 2.10/2.50    , true, 'is_a_theorem'( equivalent( equivalent( Y, Y ), X ) ), true ) ), 
% 2.10/2.50    :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 967, [ =( ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), true ), true ) ] )
% 2.10/2.50  , clause( 966, [ =( true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), true ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 36, [ =( ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), true ), true ) ] )
% 2.10/2.50  , clause( 967, [ =( ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), true ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y )] ), permutation( 0, [ ==>( 0, 0
% 2.10/2.50     )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 969, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 9, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( 
% 2.10/2.50    equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), true ), true
% 2.10/2.50     ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), 
% 2.10/2.50    :=( U, U )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 971, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 31, [ =( 'is_a_theorem'( equivalent( Y, Y ) ), true ) ] )
% 2.10/2.50  , 0, clause( 969, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, U ), :=( Y, equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( 
% 2.10/2.50    equivalent( Y, Z ), T ) ) )] ), substitution( 1, [ :=( X, X ), :=( Y, Y )
% 2.10/2.50    , :=( Z, Z ), :=( T, T ), :=( U, equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( equivalent( Y
% 2.10/2.50    , Z ), T ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 973, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( equivalent( Y
% 2.10/2.50    , Z ), T ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 971, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ) ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 974, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( equivalent( Y
% 2.10/2.50    , Z ), T ) ) ), true ) ] )
% 2.10/2.50  , clause( 973, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( 
% 2.10/2.50    equivalent( Y, Z ), T ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 39, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( equivalent( Y
% 2.10/2.50    , Z ), T ) ) ), true ) ] )
% 2.10/2.50  , clause( 974, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( equivalent( Y
% 2.10/2.50    , Z ), T ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 976, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 9, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( 
% 2.10/2.50    equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), true ), true
% 2.10/2.50     ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), 
% 2.10/2.50    :=( U, U )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 978, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Z ), T ), equivalent( equivalent( Y, Z ), 
% 2.10/2.50    equivalent( equivalent( X, Y ), T ) ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 3, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ), U ), U ) ), true ) ] )
% 2.10/2.50  , 0, clause( 976, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, 
% 2.10/2.50    equivalent( equivalent( X, Y ), T ) ), :=( U, equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Z ), T ), equivalent( equivalent( Y, Z ), equivalent( 
% 2.10/2.50    equivalent( X, Y ), T ) ) ) )] ), substitution( 1, [ :=( X, equivalent( X
% 2.10/2.50    , Y ) ), :=( Y, equivalent( X, Z ) ), :=( Z, T ), :=( T, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( X, Y ), T ) ) ), :=( U, 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Z ), T ), equivalent( equivalent( 
% 2.10/2.50    Y, Z ), equivalent( equivalent( X, Y ), T ) ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 980, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    X, Y ), Z ), equivalent( equivalent( T, Y ), equivalent( equivalent( X, T
% 2.10/2.50     ), Z ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 978, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Z ), T ), equivalent( equivalent( Y, Z ), 
% 2.10/2.50    equivalent( equivalent( X, Y ), T ) ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), Z ), equivalent( equivalent( T, Y ), 
% 2.10/2.50    equivalent( equivalent( X, T ), Z ) ) ) ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, X ), :=( Y, T ), :=( Z, Y ), :=( T, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 981, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.50     ), Z ), equivalent( equivalent( T, Y ), equivalent( equivalent( X, T ), 
% 2.10/2.50    Z ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 980, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), Z ), equivalent( equivalent( T, Y ), equivalent( 
% 2.10/2.50    equivalent( X, T ), Z ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 40, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Z )
% 2.10/2.50    , T ), equivalent( equivalent( Y, Z ), equivalent( equivalent( X, Y ), T
% 2.10/2.50     ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 981, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.50    Y ), Z ), equivalent( equivalent( T, Y ), equivalent( equivalent( X, T )
% 2.10/2.50    , Z ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Z ), :=( Z, T ), :=( T, Y )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 983, [ =( true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), true ) ) ] )
% 2.10/2.50  , clause( 36, [ =( ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 985, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( Y, Y ), equivalent( X, X ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 31, [ =( 'is_a_theorem'( equivalent( Y, Y ) ), true ) ] )
% 2.10/2.50  , 0, clause( 983, [ =( true, ifeq( 'is_a_theorem'( X ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( equivalent( Y, Y ), X ) ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Z ), :=( Y, X )] ), substitution( 1, [ 
% 2.10/2.50    :=( X, equivalent( X, X ) ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 989, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, X ), 
% 2.10/2.50    equivalent( Y, Y ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 985, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( Y, Y ), equivalent( X, X ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, X ), equivalent( Y, Y ) ) ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, Y ), :=( Y, X )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 990, [ =( 'is_a_theorem'( equivalent( equivalent( X, X ), 
% 2.10/2.50    equivalent( Y, Y ) ) ), true ) ] )
% 2.10/2.50  , clause( 989, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, X ), 
% 2.10/2.50    equivalent( Y, Y ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 43, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Y ), equivalent( 
% 2.10/2.50    X, X ) ) ), true ) ] )
% 2.10/2.50  , clause( 990, [ =( 'is_a_theorem'( equivalent( equivalent( X, X ), 
% 2.10/2.50    equivalent( Y, Y ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, Y ), :=( Y, X )] ), permutation( 0, [ ==>( 0, 0
% 2.10/2.50     )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 992, [ =( true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), true ) ) ] )
% 2.10/2.50  , clause( 36, [ =( ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 994, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( Z, Z ), equivalent( equivalent( X, X ), equivalent( Y, Y ) )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , clause( 43, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Y ), 
% 2.10/2.50    equivalent( X, X ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 992, [ =( true, ifeq( 'is_a_theorem'( X ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( equivalent( Y, Y ), X ) ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Y ), :=( Y, X )] ), substitution( 1, [ 
% 2.10/2.50    :=( X, equivalent( equivalent( X, X ), equivalent( Y, Y ) ) ), :=( Y, Z )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 996, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, X ), 
% 2.10/2.50    equivalent( equivalent( Y, Y ), equivalent( Z, Z ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 994, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( Z, Z ), equivalent( equivalent( X, X ), equivalent( Y, Y ) )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, X ), equivalent( equivalent( Y, Y ), equivalent( Z, Z ) )
% 2.10/2.50     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, Y ), :=( Y, Z ), :=( 
% 2.10/2.50    Z, X )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 997, [ =( 'is_a_theorem'( equivalent( equivalent( X, X ), 
% 2.10/2.50    equivalent( equivalent( Y, Y ), equivalent( Z, Z ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 996, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, X ), 
% 2.10/2.50    equivalent( equivalent( Y, Y ), equivalent( Z, Z ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 45, [ =( 'is_a_theorem'( equivalent( equivalent( Z, Z ), equivalent( 
% 2.10/2.50    equivalent( X, X ), equivalent( Y, Y ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 997, [ =( 'is_a_theorem'( equivalent( equivalent( X, X ), 
% 2.10/2.50    equivalent( equivalent( Y, Y ), equivalent( Z, Z ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, Z ), :=( Y, X ), :=( Z, Y )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 999, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 16, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( T, 
% 2.10/2.50    Y ), equivalent( T, Z ) ) ), true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1001, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( Z, equivalent( X, X ) ), equivalent( Z, equivalent( Y, Y ) )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , clause( 45, [ =( 'is_a_theorem'( equivalent( equivalent( Z, Z ), 
% 2.10/2.50    equivalent( equivalent( X, X ), equivalent( Y, Y ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 999, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, equivalent( X, X
% 2.10/2.50     ) )] ), substitution( 1, [ :=( X, equivalent( X, X ) ), :=( Y, 
% 2.10/2.50    equivalent( X, X ) ), :=( Z, equivalent( Y, Y ) ), :=( T, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1003, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, Y ) ), equivalent( X, equivalent( Z, Z ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1001, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( Z, equivalent( X, X ) ), equivalent( Z, equivalent( Y, Y ) )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, equivalent( Y, Y ) ), equivalent( X, equivalent( Z, Z ) )
% 2.10/2.50     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, Y ), :=( Y, Z ), :=( 
% 2.10/2.50    Z, X )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1004, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( Y
% 2.10/2.50    , Y ) ), equivalent( X, equivalent( Z, Z ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1003, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, Y ) ), equivalent( X, equivalent( Z, Z ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 51, [ =( 'is_a_theorem'( equivalent( equivalent( Z, equivalent( X, 
% 2.10/2.50    X ) ), equivalent( Z, equivalent( Y, Y ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1004, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( 
% 2.10/2.50    Y, Y ) ), equivalent( X, equivalent( Z, Z ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, Z ), :=( Y, X ), :=( Z, Y )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1006, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 9, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( 
% 2.10/2.50    equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), true ), true
% 2.10/2.50     ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), 
% 2.10/2.50    :=( U, U )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1008, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.50    equivalent( Y, Z ) ), equivalent( T, T ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 51, [ =( 'is_a_theorem'( equivalent( equivalent( Z, equivalent( X
% 2.10/2.50    , X ) ), equivalent( Z, equivalent( Y, Y ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1006, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ), 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ) ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, equivalent( Y, Z ) ), :=( Y, T ), :=( Z, 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.50    equivalent( Y, Z ) ) )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), 
% 2.10/2.50    :=( Z, Z ), :=( T, equivalent( Y, Z ) ), :=( U, equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.50     ), equivalent( T, T ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1010, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), 
% 2.10/2.50    equivalent( T, T ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1008, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.50    equivalent( Y, Z ) ), equivalent( T, T ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.50    equivalent( Y, Z ) ), equivalent( T, T ) ) ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1011, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), 
% 2.10/2.50    equivalent( T, T ) ) ), true ) ] )
% 2.10/2.50  , clause( 1010, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.50     ), equivalent( T, T ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 54, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), 
% 2.10/2.50    equivalent( T, T ) ) ), true ) ] )
% 2.10/2.50  , clause( 1011, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), 
% 2.10/2.50    equivalent( T, T ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1013, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 26, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), true
% 2.10/2.50     ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1015, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( X, Y ), equivalent( X, Z ) )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , clause( 54, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), 
% 2.10/2.50    equivalent( T, T ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1013, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z )
% 2.10/2.50     ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) )] ), substitution( 
% 2.10/2.50    1, [ :=( X, equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ), :=( Y
% 2.10/2.50    , equivalent( Y, Z ) ), :=( Z, equivalent( equivalent( X, Y ), equivalent( 
% 2.10/2.50    X, Z ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1017, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1015, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( X, Y ), equivalent( X, Z ) )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( equivalent( Z, X ), equivalent( Z, Y ) )
% 2.10/2.50     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, Z ), :=( Y, X ), :=( 
% 2.10/2.50    Z, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1018, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1017, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 101, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Z ), 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1018, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, Y ), :=( Y, Z ), :=( Z, X )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1020, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 28, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, equivalent( equivalent( Z, Z ), Y ) ) ), 
% 2.10/2.50    true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1022, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( equivalent( T, T ), equivalent( 
% 2.10/2.50    equivalent( Z, X ), equivalent( Z, Y ) ) ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 101, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Z ), 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1020, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.50    true, 'is_a_theorem'( equivalent( X, equivalent( equivalent( Z, Z ), Y )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Z ), :=( Y, X ), :=( Z, Y )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, equivalent( X, Y ) ), :=( Y, equivalent( 
% 2.10/2.50    equivalent( Z, X ), equivalent( Z, Y ) ) ), :=( Z, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1024, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( Z, Z ), equivalent( equivalent( T, X ), 
% 2.10/2.50    equivalent( T, Y ) ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1022, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( equivalent( T, T ), equivalent( 
% 2.10/2.50    equivalent( Z, X ), equivalent( Z, Y ) ) ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( equivalent( Z, Z ), equivalent( 
% 2.10/2.50    equivalent( T, X ), equivalent( T, Y ) ) ) ) ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, T ), :=( T, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1025, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( Z, Z ), equivalent( equivalent( T, X ), 
% 2.10/2.50    equivalent( T, Y ) ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1024, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( Z, Z ), equivalent( equivalent( T, X ), 
% 2.10/2.50    equivalent( T, Y ) ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 104, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( T, T ), equivalent( equivalent( Z, X ), 
% 2.10/2.50    equivalent( Z, Y ) ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1025, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( Z, Z ), equivalent( equivalent( T, X ), 
% 2.10/2.50    equivalent( T, Y ) ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, T ), :=( T, Z )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1027, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.50     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.50  , clause( 6, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), T ) ), 
% 2.10/2.50    true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1029, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ), 
% 2.10/2.50    equivalent( T, equivalent( Y, Z ) ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 101, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Z ), 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1027, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.50     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, T ), :=( Y, equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( X, Z ) ) ), :=( Z, equivalent( Y, Z ) )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, equivalent( 
% 2.10/2.50    equivalent( T, equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ), 
% 2.10/2.50    equivalent( T, equivalent( Y, Z ) ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1031, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Z ), equivalent( Y, T ) ) ), equivalent( X, 
% 2.10/2.50    equivalent( Z, T ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1029, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ), 
% 2.10/2.50    equivalent( T, equivalent( Y, Z ) ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Z ), equivalent( Y, T ) ) ), 
% 2.10/2.50    equivalent( X, equivalent( Z, T ) ) ) ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, Y ), :=( Y, Z ), :=( Z, T ), :=( T, X )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1032, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( Y, T ) ) ), equivalent( X, equivalent( Z
% 2.10/2.50    , T ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1031, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Z ), equivalent( Y, T ) ) ), equivalent( X, 
% 2.10/2.50    equivalent( Z, T ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 106, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ) ), equivalent( T, equivalent( Y
% 2.10/2.50    , Z ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1032, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( Y, T ) ) ), equivalent( X, equivalent( Z
% 2.10/2.50    , T ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, T ), :=( Y, X ), :=( Z, Y ), :=( T, Z )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1034, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.50     )
% 2.10/2.50  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.50    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.50     )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1036, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( equivalent( 
% 2.10/2.50    X, Y ) ), true, 'is_a_theorem'( equivalent( equivalent( Z, X ), 
% 2.10/2.50    equivalent( Z, Y ) ) ), true ), true ) ) ] )
% 2.10/2.50  , clause( 101, [ =( 'is_a_theorem'( equivalent( equivalent( Y, Z ), 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1034, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.50    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.50     ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Z ), :=( Y, X ), :=( Z, Y )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, equivalent( X, Y ) ), :=( Y, equivalent( 
% 2.10/2.50    equivalent( Z, X ), equivalent( Z, Y ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1041, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1036, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, Y ) ), true, 'is_a_theorem'( equivalent( equivalent( Z, X
% 2.10/2.50     ), equivalent( Z, Y ) ) ), true ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, Y ) ), true, 'is_a_theorem'( equivalent( equivalent( Z, X
% 2.10/2.50     ), equivalent( Z, Y ) ) ), true ) ), :=( Z, true )] ), substitution( 1
% 2.10/2.50    , [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1042, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ), 
% 2.10/2.50    true ), true ) ] )
% 2.10/2.50  , clause( 1041, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true
% 2.10/2.50    , 'is_a_theorem'( equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) )
% 2.10/2.50    , true ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 107, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ), 
% 2.10/2.50    true ), true ) ] )
% 2.10/2.50  , clause( 1042, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ), 
% 2.10/2.50    true ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1044, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 26, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), true
% 2.10/2.50     ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1046, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( Y, 
% 2.10/2.50    equivalent( equivalent( Z, equivalent( X, X ) ), equivalent( Z, Y ) ) ) )
% 2.10/2.50    , true ) ) ] )
% 2.10/2.50  , clause( 104, [ =( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( equivalent( T, T ), equivalent( equivalent( Z, X ), 
% 2.10/2.50    equivalent( Z, Y ) ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1044, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z )
% 2.10/2.50     ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, equivalent( X, X ) ), :=( Y, Y ), :=( Z, 
% 2.10/2.50    Z ), :=( T, X )] ), substitution( 1, [ :=( X, equivalent( X, X ) ), :=( Y
% 2.10/2.50    , Y ), :=( Z, equivalent( equivalent( Z, equivalent( X, X ) ), equivalent( 
% 2.10/2.50    Z, Y ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1048, [ =( true, 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, equivalent( Z, Z ) ), equivalent( Y, X ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1046, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    Y, equivalent( equivalent( Z, equivalent( X, X ) ), equivalent( Z, Y ) )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    X, equivalent( equivalent( Y, equivalent( Z, Z ) ), equivalent( Y, X ) )
% 2.10/2.50     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, Z ), :=( Y, X ), :=( 
% 2.10/2.50    Z, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1049, [ =( 'is_a_theorem'( equivalent( X, equivalent( equivalent( Y
% 2.10/2.50    , equivalent( Z, Z ) ), equivalent( Y, X ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1048, [ =( true, 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, equivalent( Z, Z ) ), equivalent( Y, X ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 112, [ =( 'is_a_theorem'( equivalent( Y, equivalent( equivalent( Z
% 2.10/2.50    , equivalent( X, X ) ), equivalent( Z, Y ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1049, [ =( 'is_a_theorem'( equivalent( X, equivalent( equivalent( 
% 2.10/2.50    Y, equivalent( Z, Z ) ), equivalent( Y, X ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, Y ), :=( Y, Z ), :=( Z, X )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1051, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 26, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z ) ), true
% 2.10/2.50     ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1053, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( Z, 
% 2.10/2.50    equivalent( X, equivalent( equivalent( X, equivalent( Y, Y ) ), Z ) ) ) )
% 2.10/2.50    , true ) ) ] )
% 2.10/2.50  , clause( 112, [ =( 'is_a_theorem'( equivalent( Y, equivalent( equivalent( 
% 2.10/2.50    Z, equivalent( X, X ) ), equivalent( Z, Y ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1051, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( Y, Z )
% 2.10/2.50     ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Y ), :=( Y, equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, Y ) ), Z ) ), :=( Z, X )] ), substitution( 1, [ :=( X, 
% 2.10/2.50    equivalent( X, equivalent( Y, Y ) ) ), :=( Y, Z ), :=( Z, equivalent( X, 
% 2.10/2.50    equivalent( equivalent( X, equivalent( Y, Y ) ), Z ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1055, [ =( true, 'is_a_theorem'( equivalent( X, equivalent( Y, 
% 2.10/2.50    equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1053, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    Z, equivalent( X, equivalent( equivalent( X, equivalent( Y, Y ) ), Z ) )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    X, equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) )
% 2.10/2.50     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, Y ), :=( Y, Z ), :=( 
% 2.10/2.50    Z, X )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1056, [ =( 'is_a_theorem'( equivalent( X, equivalent( Y, equivalent( 
% 2.10/2.50    equivalent( Y, equivalent( Z, Z ) ), X ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1055, [ =( true, 'is_a_theorem'( equivalent( X, equivalent( Y, 
% 2.10/2.50    equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 118, [ =( 'is_a_theorem'( equivalent( Z, equivalent( X, equivalent( 
% 2.10/2.50    equivalent( X, equivalent( Y, Y ) ), Z ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1056, [ =( 'is_a_theorem'( equivalent( X, equivalent( Y, 
% 2.10/2.50    equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, Z ), :=( Y, X ), :=( Z, Y )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1058, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.50     )
% 2.10/2.50  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.50    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.50     )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1061, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ), 
% 2.10/2.50    T ) ), true, ifeq( true, true, 'is_a_theorem'( T ), true ), true ) ) ] )
% 2.10/2.50  , clause( 118, [ =( 'is_a_theorem'( equivalent( Z, equivalent( X, 
% 2.10/2.50    equivalent( equivalent( X, equivalent( Y, Y ) ), Z ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1058, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.50    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.50     ) ) ] )
% 2.10/2.50  , 0, 19, substitution( 0, [ :=( X, Y ), :=( Y, Z ), :=( Z, X )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, equivalent( X, equivalent( Y, equivalent( 
% 2.10/2.50    equivalent( Y, equivalent( Z, Z ) ), X ) ) ) ), :=( Y, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1063, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ), 
% 2.10/2.50    T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1061, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    X, equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) )
% 2.10/2.50     ), T ) ), true, ifeq( true, true, 'is_a_theorem'( T ), true ), true ) )
% 2.10/2.50     ] )
% 2.10/2.50  , 0, 18, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( T ) ), 
% 2.10/2.50    :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), 
% 2.10/2.50    :=( T, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1064, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ), 
% 2.10/2.50    T ) ), true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.50  , clause( 1063, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X
% 2.10/2.50    , equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) )
% 2.10/2.50    , T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 129, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ), 
% 2.10/2.50    T ) ), true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.50  , clause( 1064, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ), 
% 2.10/2.50    T ) ), true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1066, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.50     ) ), equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 7, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), 
% 2.10/2.50    equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), true )
% 2.10/2.50    , true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T ), 
% 2.10/2.50    :=( U, U )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1068, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ), equivalent( equivalent( equivalent( 
% 2.10/2.50    X, Y ), equivalent( X, Z ) ), T ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 39, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), T ), equivalent( equivalent( Y
% 2.10/2.50    , Z ), T ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1066, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z
% 2.10/2.50     ) ), equivalent( Y, Z ) ), T ), T ), U ) ), true, 'is_a_theorem'( U ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( X, Z ) ) ), :=( Y, equivalent( Y, Z ) ), :=( Z, T ), :=( T, 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ) )] )
% 2.10/2.50    , substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, 
% 2.10/2.50    equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ) ), 
% 2.10/2.50    :=( U, equivalent( equivalent( equivalent( Y, Z ), T ), equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), T ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1070, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    X, Y ), Z ), equivalent( equivalent( equivalent( T, X ), equivalent( T, Y
% 2.10/2.50     ) ), Z ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1068, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( Y, Z ), T ), equivalent( equivalent( equivalent( 
% 2.10/2.50    X, Y ), equivalent( X, Z ) ), T ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), Z ), equivalent( equivalent( equivalent( 
% 2.10/2.50    T, X ), equivalent( T, Y ) ), Z ) ) ) ), :=( Z, true )] ), substitution( 
% 2.10/2.50    1, [ :=( X, T ), :=( Y, X ), :=( Z, Y ), :=( T, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1071, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.50     ), Z ), equivalent( equivalent( equivalent( T, X ), equivalent( T, Y ) )
% 2.10/2.50    , Z ) ) ), true ) ] )
% 2.10/2.50  , clause( 1070, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), Z ), equivalent( equivalent( equivalent( T, X ), 
% 2.10/2.50    equivalent( T, Y ) ), Z ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 138, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( Y, Z
% 2.10/2.50     ), T ), equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z ) )
% 2.10/2.50    , T ) ) ), true ) ] )
% 2.10/2.50  , clause( 1071, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X
% 2.10/2.50    , Y ), Z ), equivalent( equivalent( equivalent( T, X ), equivalent( T, Y
% 2.10/2.50     ) ), Z ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, Y ), :=( Y, Z ), :=( Z, T ), :=( T, X )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1073, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.50     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.50  , clause( 6, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z ) ), T ) ), 
% 2.10/2.50    true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1075, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, equivalent( X, Z ) ), equivalent( equivalent( equivalent( 
% 2.10/2.50    X, Y ), T ), equivalent( Y, Z ) ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 40, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Z
% 2.10/2.50     ), T ), equivalent( equivalent( Y, Z ), equivalent( equivalent( X, Y ), 
% 2.10/2.50    T ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1073, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( X, Z ) ), equivalent( Y, Z )
% 2.10/2.50     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, equivalent( X, Y ) ), :=( Y, T ), :=( Z, 
% 2.10/2.50    equivalent( X, Z ) ), :=( T, equivalent( Y, Z ) )] ), substitution( 1, [ 
% 2.10/2.50    :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, equivalent( equivalent( T, 
% 2.10/2.50    equivalent( X, Z ) ), equivalent( equivalent( equivalent( X, Y ), T ), 
% 2.10/2.50    equivalent( Y, Z ) ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1077, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, Z ) ), equivalent( equivalent( equivalent( Y, T ), X ), 
% 2.10/2.50    equivalent( T, Z ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1075, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, equivalent( X, Z ) ), equivalent( equivalent( equivalent( 
% 2.10/2.50    X, Y ), T ), equivalent( Y, Z ) ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, equivalent( Y, Z ) ), equivalent( equivalent( equivalent( 
% 2.10/2.50    Y, T ), X ), equivalent( T, Z ) ) ) ) ), :=( Z, true )] ), substitution( 
% 2.10/2.50    1, [ :=( X, Y ), :=( Y, T ), :=( Z, Z ), :=( T, X )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1078, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( Y
% 2.10/2.50    , Z ) ), equivalent( equivalent( equivalent( Y, T ), X ), equivalent( T, 
% 2.10/2.50    Z ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1077, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, Z ) ), equivalent( equivalent( equivalent( Y, T ), X ), 
% 2.10/2.50    equivalent( T, Z ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 152, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( X
% 2.10/2.50    , Z ) ), equivalent( equivalent( equivalent( X, Y ), T ), equivalent( Y, 
% 2.10/2.50    Z ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1078, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( 
% 2.10/2.50    Y, Z ) ), equivalent( equivalent( equivalent( Y, T ), X ), equivalent( T
% 2.10/2.50    , Z ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, T ), :=( Y, X ), :=( Z, Z ), :=( T, Y )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1080, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.50     )
% 2.10/2.50  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.50    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.50     )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1082, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( equivalent( 
% 2.10/2.50    X, equivalent( equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, equivalent( Z, T ) ) ), true ), true ) ) ]
% 2.10/2.50     )
% 2.10/2.50  , clause( 106, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( X, Z ) ) ), equivalent( T, equivalent( Y
% 2.10/2.50    , Z ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1080, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.50    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.50     ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Y ), :=( Y, Z ), :=( Z, T ), :=( T, X )] )
% 2.10/2.50    , substitution( 1, [ :=( X, equivalent( X, equivalent( equivalent( Y, Z )
% 2.10/2.50    , equivalent( Y, T ) ) ) ), :=( Y, equivalent( X, equivalent( Z, T ) ) )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1087, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( Z, T ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1082, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Z ), equivalent( Y, T ) ) ) ), 
% 2.10/2.50    true, 'is_a_theorem'( equivalent( X, equivalent( Z, T ) ) ), true ), true
% 2.10/2.50     ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Z ), equivalent( Y, T ) ) ) ), 
% 2.10/2.50    true, 'is_a_theorem'( equivalent( X, equivalent( Z, T ) ) ), true ) ), 
% 2.10/2.50    :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), 
% 2.10/2.50    :=( T, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1088, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( Z, T ) ) ), true ), true ) ] )
% 2.10/2.50  , clause( 1087, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( Z, T ) ) ), true ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 230, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( Z, T ) ) ), true ), true ) ] )
% 2.10/2.50  , clause( 1088, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( Z, T ) ) ), true ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1090, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ), 
% 2.10/2.50    T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.50  , clause( 129, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) ) ), 
% 2.10/2.50    T ) ), true, 'is_a_theorem'( T ), true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1092, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( Y, T ), X ), equivalent( T, equivalent( 
% 2.10/2.50    equivalent( Y, equivalent( Z, Z ) ), X ) ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 152, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.50    X, Z ) ), equivalent( equivalent( equivalent( X, Y ), T ), equivalent( Y
% 2.10/2.50    , Z ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1090, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    X, equivalent( Y, equivalent( equivalent( Y, equivalent( Z, Z ) ), X ) )
% 2.10/2.50     ), T ) ), true, 'is_a_theorem'( T ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Y ), :=( Y, T ), :=( Z, equivalent( 
% 2.10/2.50    equivalent( Y, equivalent( Z, Z ) ), X ) ), :=( T, X )] ), substitution( 
% 2.10/2.50    1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, equivalent( equivalent( 
% 2.10/2.50    equivalent( Y, T ), X ), equivalent( T, equivalent( equivalent( Y, 
% 2.10/2.50    equivalent( Z, Z ) ), X ) ) ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1094, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    X, Y ), Z ), equivalent( Y, equivalent( equivalent( X, equivalent( T, T )
% 2.10/2.50     ), Z ) ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1092, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( Y, T ), X ), equivalent( T, equivalent( 
% 2.10/2.50    equivalent( Y, equivalent( Z, Z ) ), X ) ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), Z ), equivalent( Y, equivalent( 
% 2.10/2.50    equivalent( X, equivalent( T, T ) ), Z ) ) ) ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, Z ), :=( Y, X ), :=( Z, T ), :=( T, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1095, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.50     ), Z ), equivalent( Y, equivalent( equivalent( X, equivalent( T, T ) ), 
% 2.10/2.50    Z ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1094, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), Z ), equivalent( Y, equivalent( equivalent( X, 
% 2.10/2.50    equivalent( T, T ) ), Z ) ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 345, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( Y, T
% 2.10/2.50     ), X ), equivalent( T, equivalent( equivalent( Y, equivalent( Z, Z ) ), 
% 2.10/2.50    X ) ) ) ), true ) ] )
% 2.10/2.50  , clause( 1095, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X
% 2.10/2.50    , Y ), Z ), equivalent( Y, equivalent( equivalent( X, equivalent( T, T )
% 2.10/2.50     ), Z ) ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, Y ), :=( Y, T ), :=( Z, X ), :=( T, Z )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1097, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( Z, T ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 230, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( Z, T ) ) ), true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1099, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( equivalent( Z, X ), T ) ), 
% 2.10/2.50    equivalent( equivalent( Z, Y ), T ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 138, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( Y, 
% 2.10/2.50    Z ), T ), equivalent( equivalent( equivalent( X, Y ), equivalent( X, Z )
% 2.10/2.50     ), T ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1097, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Z ), equivalent( Y, T ) ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, equivalent( Z, T ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Z ), :=( Y, X ), :=( Z, Y ), :=( T, 
% 2.10/2.50    equivalent( equivalent( Z, X ), T ) )] ), substitution( 1, [ :=( X, 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( equivalent( Z, X ), T ) ) ), 
% 2.10/2.50    :=( Y, equivalent( Z, X ) ), :=( Z, equivalent( Z, Y ) ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1101, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    X, Y ), equivalent( equivalent( Z, X ), T ) ), equivalent( equivalent( Z
% 2.10/2.50    , Y ), T ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1099, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( equivalent( Z, X ), T ) ), 
% 2.10/2.50    equivalent( equivalent( Z, Y ), T ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( equivalent( Z, X ), T ) ), 
% 2.10/2.50    equivalent( equivalent( Z, Y ), T ) ) ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1102, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( equivalent( Z, X ), T ) ), equivalent( equivalent( Z, Y )
% 2.10/2.50    , T ) ) ), true ) ] )
% 2.10/2.50  , clause( 1101, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( equivalent( Z, X ), T ) ), equivalent( 
% 2.10/2.50    equivalent( Z, Y ), T ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 367, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( equivalent( Z, X ), T ) ), equivalent( equivalent( Z, Y )
% 2.10/2.50    , T ) ) ), true ) ] )
% 2.10/2.50  , clause( 1102, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X
% 2.10/2.50    , Y ), equivalent( equivalent( Z, X ), T ) ), equivalent( equivalent( Z, 
% 2.10/2.50    Y ), T ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1104, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 16, [ =( ifeq( 'is_a_theorem'( equivalent( equivalent( X, Y ), 
% 2.10/2.50    equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( equivalent( T, 
% 2.10/2.50    Y ), equivalent( T, Z ) ) ), true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1106, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, equivalent( equivalent( X, X ), Z ) ), equivalent( T, Z )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , clause( 367, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.50    Y ), equivalent( equivalent( Z, X ), T ) ), equivalent( equivalent( Z, Y
% 2.10/2.50     ), T ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1104, [ =( true, ifeq( 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    X, Y ), equivalent( X, Z ) ) ), true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, Y ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, X ), :=( T, Z )] )
% 2.10/2.50    , substitution( 1, [ :=( X, equivalent( X, Y ) ), :=( Y, equivalent( 
% 2.10/2.50    equivalent( X, X ), Z ) ), :=( Z, Z ), :=( T, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1108, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Y ), Z ) ), equivalent( X, Z ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1106, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, equivalent( equivalent( X, X ), Z ) ), equivalent( T, Z )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Y ), Z ) ), equivalent( X, Z )
% 2.10/2.50     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, Y ), :=( Y, T ), :=( 
% 2.10/2.50    Z, Z ), :=( T, X )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1109, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Y ), Z ) ), equivalent( X, Z ) ) ), true ) ] )
% 2.10/2.50  , clause( 1108, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Y ), Z ) ), equivalent( X, Z ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 376, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.50    equivalent( X, X ), Z ) ), equivalent( T, Z ) ) ), true ) ] )
% 2.10/2.50  , clause( 1109, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Y ), Z ) ), equivalent( X, Z ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, T ), :=( Y, X ), :=( Z, Z )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1111, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.50     )
% 2.10/2.50  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.50    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.50     )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1113, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( equivalent( 
% 2.10/2.50    X, equivalent( equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, Z ) ), true ), true ) ) ] )
% 2.10/2.50  , clause( 376, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.50    equivalent( X, X ), Z ) ), equivalent( T, Z ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1111, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.50    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.50     ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Y ), :=( Y, T ), :=( Z, Z ), :=( T, X )] )
% 2.10/2.50    , substitution( 1, [ :=( X, equivalent( X, equivalent( equivalent( Y, Y )
% 2.10/2.50    , Z ) ) ), :=( Y, equivalent( X, Z ) )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1118, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( equivalent( X, Z ) ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1113, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Y ), Z ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, Z ) ), true ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Y ), Z ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, Z ) ), true ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1119, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( equivalent( X, Z ) ), 
% 2.10/2.50    true ), true ) ] )
% 2.10/2.50  , clause( 1118, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( equivalent( X, Z ) ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 454, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( equivalent( X, Z ) ), 
% 2.10/2.50    true ), true ) ] )
% 2.10/2.50  , clause( 1119, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( equivalent( X, Z ) ), 
% 2.10/2.50    true ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1121, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( equivalent( X, Z ) ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 454, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( equivalent( X, Z ) ), 
% 2.10/2.50    true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1123, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( equivalent( Y, X ), Z ) ), Z
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , clause( 367, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.50    Y ), equivalent( equivalent( Z, X ), T ) ), equivalent( equivalent( Z, Y
% 2.10/2.50     ), T ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1121, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Y ), Z ) ) ), true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    X, Z ) ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Y ), :=( T, Z )] )
% 2.10/2.50    , substitution( 1, [ :=( X, equivalent( equivalent( X, Y ), equivalent( 
% 2.10/2.50    equivalent( Y, X ), Z ) ) ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1125, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    X, Y ), equivalent( equivalent( Y, X ), Z ) ), Z ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1123, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( equivalent( Y, X ), Z ) ), Z
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, Y ), equivalent( equivalent( Y, X ), Z ) ), Z
% 2.10/2.50     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( 
% 2.10/2.50    Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1126, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( equivalent( Y, X ), Z ) ), Z ) ), true ) ] )
% 2.10/2.50  , clause( 1125, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( equivalent( Y, X ), Z ) ), Z ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 489, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, Y
% 2.10/2.50     ), equivalent( equivalent( Y, X ), Z ) ), Z ) ), true ) ] )
% 2.10/2.50  , clause( 1126, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X
% 2.10/2.50    , Y ), equivalent( equivalent( Y, X ), Z ) ), Z ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1128, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , clause( 107, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( equivalent( Z, X ), equivalent( Z, Y ) ) ), 
% 2.10/2.50    true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1130, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, equivalent( equivalent( X, Y ), equivalent( equivalent( Y
% 2.10/2.50    , X ), Z ) ) ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.50  , clause( 489, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.50    Y ), equivalent( equivalent( Y, X ), Z ) ), Z ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1128, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.50    true, 'is_a_theorem'( equivalent( equivalent( Z, X ), equivalent( Z, Y )
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, equivalent( equivalent( X, Y ), equivalent( 
% 2.10/2.50    equivalent( Y, X ), Z ) ) ), :=( Y, Z ), :=( Z, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1134, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ), 
% 2.10/2.50    equivalent( X, T ) ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1130, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( T, equivalent( equivalent( X, Y ), equivalent( equivalent( Y
% 2.10/2.50    , X ), Z ) ) ), equivalent( T, Z ) ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Z ), equivalent( equivalent( Z
% 2.10/2.50    , Y ), T ) ) ), equivalent( X, T ) ) ) ), :=( Z, true )] ), 
% 2.10/2.50    substitution( 1, [ :=( X, Y ), :=( Y, Z ), :=( Z, T ), :=( T, X )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1135, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ), equivalent( 
% 2.10/2.50    X, T ) ) ), true ) ] )
% 2.10/2.50  , clause( 1134, [ =( true, 'is_a_theorem'( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ), 
% 2.10/2.50    equivalent( X, T ) ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 522, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( equivalent( Y, X ), Z ) ) ), equivalent( 
% 2.10/2.50    T, Z ) ) ), true ) ] )
% 2.10/2.50  , clause( 1135, [ =( 'is_a_theorem'( equivalent( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ), equivalent( 
% 2.10/2.50    X, T ) ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, T ), :=( Y, X ), :=( Z, Y ), :=( T, Z )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1137, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, 
% 2.10/2.50    ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ) ) ]
% 2.10/2.50     )
% 2.10/2.50  , clause( 1, [ =( ifeq( 'is_a_theorem'( equivalent( X, Y ) ), true, ifeq( 
% 2.10/2.50    'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true ), true ) ]
% 2.10/2.50     )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1139, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( equivalent( 
% 2.10/2.50    X, equivalent( equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) )
% 2.10/2.50     ) ), true, 'is_a_theorem'( equivalent( X, T ) ), true ), true ) ) ] )
% 2.10/2.50  , clause( 522, [ =( 'is_a_theorem'( equivalent( equivalent( T, equivalent( 
% 2.10/2.50    equivalent( X, Y ), equivalent( equivalent( Y, X ), Z ) ) ), equivalent( 
% 2.10/2.50    T, Z ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1137, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, Y ) ), 
% 2.10/2.50    true, ifeq( 'is_a_theorem'( X ), true, 'is_a_theorem'( Y ), true ), true
% 2.10/2.50     ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Y ), :=( Y, Z ), :=( Z, T ), :=( T, X )] )
% 2.10/2.50    , substitution( 1, [ :=( X, equivalent( X, equivalent( equivalent( Y, Z )
% 2.10/2.50    , equivalent( equivalent( Z, Y ), T ) ) ) ), :=( Y, equivalent( X, T ) )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1144, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, T ) ), true ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1139, [ =( true, ifeq( true, true, ifeq( 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Z ), equivalent( equivalent( Z
% 2.10/2.50    , Y ), T ) ) ) ), true, 'is_a_theorem'( equivalent( X, T ) ), true ), 
% 2.10/2.50    true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, ifeq( 'is_a_theorem'( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Z ), equivalent( equivalent( Z
% 2.10/2.50    , Y ), T ) ) ) ), true, 'is_a_theorem'( equivalent( X, T ) ), true ) ), 
% 2.10/2.50    :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), 
% 2.10/2.50    :=( T, T )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1145, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, T ) ), true ), true ) ] )
% 2.10/2.50  , clause( 1144, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, T ) ), true ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 641, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, T ) ), true ), true ) ] )
% 2.10/2.50  , clause( 1145, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, T ) ), true ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1147, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, T ) ), true ) ) ] )
% 2.10/2.50  , clause( 641, [ =( ifeq( 'is_a_theorem'( equivalent( X, equivalent( 
% 2.10/2.50    equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ) ), true, 
% 2.10/2.50    'is_a_theorem'( equivalent( X, T ) ), true ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z ), :=( T, T )] )
% 2.10/2.50    ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1149, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, equivalent( equivalent( Y, Y ), X ) ), Z ), Z
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , clause( 345, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( Y, 
% 2.10/2.50    T ), X ), equivalent( T, equivalent( equivalent( Y, equivalent( Z, Z ) )
% 2.10/2.50    , X ) ) ) ), true ) ] )
% 2.10/2.50  , 0, clause( 1147, [ =( true, ifeq( 'is_a_theorem'( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Z ), equivalent( equivalent( Z, Y ), T ) ) ) )
% 2.10/2.50    , true, 'is_a_theorem'( equivalent( X, T ) ), true ) ) ] )
% 2.10/2.50  , 0, 3, substitution( 0, [ :=( X, Z ), :=( Y, X ), :=( Z, Y ), :=( T, 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) )] ), substitution( 1, [ :=( X, 
% 2.10/2.50    equivalent( equivalent( X, equivalent( equivalent( Y, Y ), X ) ), Z ) ), 
% 2.10/2.50    :=( Y, equivalent( Y, Y ) ), :=( Z, X ), :=( T, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  paramod(
% 2.10/2.50  clause( 1151, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    X, equivalent( equivalent( Y, Y ), X ) ), Z ), Z ) ) ) ] )
% 2.10/2.50  , clause( 0, [ =( ifeq( X, X, Y, Z ), Y ) ] )
% 2.10/2.50  , 0, clause( 1149, [ =( true, ifeq( true, true, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, equivalent( equivalent( Y, Y ), X ) ), Z ), Z
% 2.10/2.50     ) ), true ) ) ] )
% 2.10/2.50  , 0, 2, substitution( 0, [ :=( X, true ), :=( Y, 'is_a_theorem'( equivalent( 
% 2.10/2.50    equivalent( equivalent( X, equivalent( equivalent( Y, Y ), X ) ), Z ), Z
% 2.10/2.50     ) ) ), :=( Z, true )] ), substitution( 1, [ :=( X, X ), :=( Y, Y ), :=( 
% 2.10/2.50    Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1152, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), Z ), Z ) ), true ) ] )
% 2.10/2.50  , clause( 1151, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Y ), X ) ), Z ), Z ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 818, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), Z ), Z ) ), true ) ] )
% 2.10/2.50  , clause( 1152, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X
% 2.10/2.50    , equivalent( equivalent( Y, Y ), X ) ), Z ), Z ) ), true ) ] )
% 2.10/2.50  , substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] ), 
% 2.10/2.50    permutation( 0, [ ==>( 0, 0 )] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1153, [ =( true, 'is_a_theorem'( equivalent( equivalent( equivalent( 
% 2.10/2.50    X, equivalent( equivalent( Y, Y ), X ) ), Z ), Z ) ) ) ] )
% 2.10/2.50  , clause( 818, [ =( 'is_a_theorem'( equivalent( equivalent( equivalent( X, 
% 2.10/2.50    equivalent( equivalent( Y, Y ), X ) ), Z ), Z ) ), true ) ] )
% 2.10/2.50  , 0, substitution( 0, [ :=( X, X ), :=( Y, Y ), :=( Z, Z )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  eqswap(
% 2.10/2.50  clause( 1154, [ ~( =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( a, equivalent( equivalent( b, b ), a ) ), c ), c ) ) ) ) ] )
% 2.10/2.50  , clause( 5, [ ~( =( 'is_a_theorem'( equivalent( equivalent( equivalent( a
% 2.10/2.50    , equivalent( equivalent( b, b ), a ) ), c ), c ) ), true ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  resolution(
% 2.10/2.50  clause( 1155, [] )
% 2.10/2.50  , clause( 1154, [ ~( =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( a, equivalent( equivalent( b, b ), a ) ), c ), c ) ) ) ) ] )
% 2.10/2.50  , 0, clause( 1153, [ =( true, 'is_a_theorem'( equivalent( equivalent( 
% 2.10/2.50    equivalent( X, equivalent( equivalent( Y, Y ), X ) ), Z ), Z ) ) ) ] )
% 2.10/2.50  , 0, substitution( 0, [] ), substitution( 1, [ :=( X, a ), :=( Y, b ), :=( 
% 2.10/2.50    Z, c )] )).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  subsumption(
% 2.10/2.50  clause( 820, [] )
% 2.10/2.50  , clause( 1155, [] )
% 2.10/2.50  , substitution( 0, [] ), permutation( 0, [] ) ).
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  end.
% 2.10/2.50  
% 2.10/2.50  % ABCDEFGHIJKLMNOPQRSTUVWXYZ
% 2.10/2.50  
% 2.10/2.50  Memory use:
% 2.10/2.50  
% 2.10/2.50  space for terms:        15830
% 2.10/2.50  space for clauses:      119154
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  clauses generated:      259784
% 2.10/2.50  clauses kept:           821
% 2.10/2.50  clauses selected:       737
% 2.10/2.50  clauses deleted:        11
% 2.10/2.50  clauses inuse deleted:  0
% 2.10/2.50  
% 2.10/2.50  subsentry:          693
% 2.10/2.50  literals s-matched: 234
% 2.10/2.50  literals matched:   234
% 2.10/2.50  full subsumption:   0
% 2.10/2.50  
% 2.10/2.50  checksum:           1305354707
% 2.10/2.50  
% 2.10/2.50  
% 2.10/2.50  Bliksem ended
%------------------------------------------------------------------------------