| Step | Hyp | Ref
 | Expression | 
| 1 |   | df-op 4567 | 
. . . . 5
                     
       Phi             
       
 
Phi      0c     | 
| 2 | 1 | eleq2i 2417 | 
. . . 4
     Phi      0c  
             Phi
     0c    
     
            Phi
                       Phi      0c      | 
| 3 |   | elun 3221 | 
. . . . 5
     Phi      0c  
     
              Phi
                       Phi      0c          Phi      0c  
                 
 Phi        Phi      0c  
                 
 
Phi      0c      | 
| 4 |   | vex 2863 | 
. . . . . . . . 9
        | 
| 5 | 4 | phiex 4573 | 
. . . . . . . 8
   Phi       | 
| 6 |   | snex 4112 | 
. . . . . . . 8
   0c      | 
| 7 | 5, 6 | unex 4107 | 
. . . . . . 7
    Phi
     0c    
  | 
| 8 |   | eqeq1 2359 | 
. . . . . . . 8
         Phi      0c           Phi
      Phi
     0c    
 Phi     | 
| 9 | 8 | rexbidv 2636 | 
. . . . . . 7
         Phi      0c                  Phi
             Phi      0c      Phi     | 
| 10 | 7, 9 | elab 2986 | 
. . . . . 6
     Phi      0c  
                 
 Phi               Phi      0c      Phi    | 
| 11 |   | phi011 4600 | 
. . . . . . . . 9
             Phi
     0c    
 
Phi      0c    | 
| 12 |   | equcom 1680 | 
. . . . . . . . 9
                  | 
| 13 | 11, 12 | bitr3i 242 | 
. . . . . . . 8
     Phi      0c  
    Phi      0c  
 
       | 
| 14 | 13 | rexbii 2640 | 
. . . . . . 7
       
    Phi      0c  
    Phi      0c  
 
              | 
| 15 |   | eqeq1 2359 | 
. . . . . . . . 9
         Phi      0c            Phi      0c  
 
 
Phi      0c    
 
Phi      0c     | 
| 16 | 15 | rexbidv 2636 | 
. . . . . . . 8
         Phi      0c                   Phi      0c  
 
         Phi      0c       Phi      0c     | 
| 17 | 7, 16 | elab 2986 | 
. . . . . . 7
     Phi      0c  
                 
 
Phi      0c               Phi      0c       Phi      0c    | 
| 18 |   | risset 2662 | 
. . . . . . 7
                         | 
| 19 | 14, 17, 18 | 3bitr4i 268 | 
. . . . . 6
     Phi      0c  
                 
 
Phi      0c             | 
| 20 | 10, 19 | orbi12i 507 | 
. . . . 5
      Phi      0c         
            Phi
       Phi      0c         
             Phi      0c            
    Phi      0c  
   Phi             | 
| 21 | 3, 20 | bitri 240 | 
. . . 4
     Phi      0c  
     
              Phi
                       Phi      0c            
    Phi      0c  
   Phi             | 
| 22 | 2, 21 | bitri 240 | 
. . 3
     Phi      0c  
                
    Phi      0c  
   Phi             | 
| 23 |   | phieq 4571 | 
. . . . . 6
           
Phi      Phi
   | 
| 24 | 23 | uneq1d 3418 | 
. . . . 5
             Phi      0c       Phi
     0c    | 
| 25 | 24 | eleq1d 2419 | 
. . . 4
              Phi      0c        
       Phi      0c  
           | 
| 26 |   | df-proj2 4569 | 
. . . 4
   Proj2                 Phi      0c             | 
| 27 | 4, 25, 26 | elab2 2989 | 
. . 3
        Proj2    
       Phi      0c  
          | 
| 28 |   | 0cnelphi 4598 | 
. . . . . . . 8
    0c
   Phi   | 
| 29 |   | ssun2 3428 | 
. . . . . . . . . 10
   0c      Phi      0c   | 
| 30 |   | 0cex 4393 | 
. . . . . . . . . . 11
 
0c  
  | 
| 31 | 30 | snid 3761 | 
. . . . . . . . . 10
 
0c  
 0c  | 
| 32 | 29, 31 | sselii 3271 | 
. . . . . . . . 9
 
0c  
 
Phi      0c   | 
| 33 |   | eleq2 2414 | 
. . . . . . . . 9
     Phi      0c  
   Phi      0c     Phi      0c  
 
0c  
 Phi     | 
| 34 | 32, 33 | mpbii 202 | 
. . . . . . . 8
     Phi      0c  
   Phi    
0c  
 Phi    | 
| 35 | 28, 34 | mto 167 | 
. . . . . . 7
      Phi      0c  
   Phi   | 
| 36 | 35 | a1i 10 | 
. . . . . 6
               Phi      0c      Phi
   | 
| 37 | 36 | nrex 2717 | 
. . . . 5
        
    Phi      0c  
   Phi   | 
| 38 | 37 | biorfi 396 | 
. . . 4
                        
    Phi      0c  
   Phi     | 
| 39 |   | orcom 376 | 
. . . 4
                     Phi      0c  
   Phi           
    Phi      0c  
   Phi             | 
| 40 | 38, 39 | bitri 240 | 
. . 3
                
    Phi      0c  
   Phi             | 
| 41 | 22, 27, 40 | 3bitr4i 268 | 
. 2
        Proj2    
            | 
| 42 | 41 | eqriv 2350 | 
1
   Proj2            |