| Step | Hyp | Ref
 | Expression | 
| 1 |   | brcnv 4893 | 
. . . . . . . . . 10
               | 
| 2 |   | vex 2863 | 
. . . . . . . . . . 11
        | 
| 3 | 2 | br1st 4859 | 
. . . . . . . . . 10
      
 
      
        | 
| 4 | 1, 3 | bitri 240 | 
. . . . . . . . 9
                
        | 
| 5 | 4 | anbi1i 676 | 
. . . . . . . 8
              AddC         1c             
     
        AddC         1c       | 
| 6 |   | 19.41v 1901 | 
. . . . . . . 8
             
        AddC         1c             
     
        AddC         1c       | 
| 7 | 5, 6 | bitr4i 243 | 
. . . . . . 7
              AddC         1c            
     
        AddC         1c       | 
| 8 | 7 | exbii 1582 | 
. . . . . 6
                AddC         1c                             AddC         1c       | 
| 9 |   | excom 1741 | 
. . . . . . 7
                        AddC         1c                    
        AddC         1c       | 
| 10 |   | vex 2863 | 
. . . . . . . . . 10
        | 
| 11 | 2, 10 | opex 4589 | 
. . . . . . . . 9
             | 
| 12 |   | breq1 4643 | 
. . . . . . . . . 10
                   
AddC         1c               AddC         1c       | 
| 13 |   | brres 4950 | 
. . . . . . . . . . 11
      
    AddC         1c              
AddC                    1c     | 
| 14 | 2, 10 | braddcfn 5827 | 
. . . . . . . . . . . 12
      
   AddC
                 | 
| 15 |   | opelxp 4812 | 
. . . . . . . . . . . . . 14
      
           1c                   1c    | 
| 16 | 2, 15 | mpbiran 884 | 
. . . . . . . . . . . . 13
      
           1c          1c   | 
| 17 |   | elsn 3749 | 
. . . . . . . . . . . . 13
        1c        1c  | 
| 18 | 16, 17 | bitri 240 | 
. . . . . . . . . . . 12
      
           1c        
1c  | 
| 19 | 14, 18 | anbi12ci 679 | 
. . . . . . . . . . 11
           AddC
                   1c   
 
     1c            
    | 
| 20 | 13, 19 | bitri 240 | 
. . . . . . . . . 10
      
    AddC         1c            1c                 | 
| 21 | 12, 20 | syl6bb 252 | 
. . . . . . . . 9
                   
AddC         1c            1c            
     | 
| 22 | 11, 21 | ceqsexv 2895 | 
. . . . . . . 8
             
        AddC         1c             1c            
    | 
| 23 | 22 | exbii 1582 | 
. . . . . . 7
                        AddC         1c              
1c          
      | 
| 24 | 9, 23 | bitri 240 | 
. . . . . 6
                        AddC         1c              
1c          
      | 
| 25 | 8, 24 | bitri 240 | 
. . . . 5
                AddC         1c            
  1c
                | 
| 26 |   | 1cex 4143 | 
. . . . . 6
 
1c  
  | 
| 27 |   | addceq2 4385 | 
. . . . . . 7
       1c            
     1c   | 
| 28 | 27 | eqeq1d 2361 | 
. . . . . 6
       1c           
        
 
1c 
      | 
| 29 | 26, 28 | ceqsexv 2895 | 
. . . . 5
          1c                       1c   
   | 
| 30 | 25, 29 | bitri 240 | 
. . . 4
                AddC         1c             1c   
   | 
| 31 |   | opelco 4885 | 
. . . 4
      
        AddC         1c   
     
 
             AddC         1c       | 
| 32 |   | mptv 5719 | 
. . . . . 6
                1c                        1c   | 
| 33 | 32 | eleq2i 2417 | 
. . . . 5
      
                
 
1c                                 1c    | 
| 34 |   | vex 2863 | 
. . . . . 6
        | 
| 35 |   | addceq1 4384 | 
. . . . . . 7
                1c         1c   | 
| 36 | 35 | eqeq2d 2364 | 
. . . . . 6
               
     1c             1c    | 
| 37 |   | eqeq1 2359 | 
. . . . . . 7
               
     1c             1c    | 
| 38 |   | eqcom 2355 | 
. . . . . . 7
            1c      
 
1c 
     | 
| 39 | 37, 38 | syl6bb 252 | 
. . . . . 6
               
     1c        
1c 
      | 
| 40 | 2, 34, 36, 39 | opelopab 4709 | 
. . . . 5
      
                       
1c          1c   
   | 
| 41 | 33, 40 | bitri 240 | 
. . . 4
      
                
 
1c          1c   
   | 
| 42 | 30, 31, 41 | 3bitr4ri 269 | 
. . 3
      
                
 
1c                 AddC         1c   
       | 
| 43 | 42 | eqrelriv 4851 | 
. 2
                1c        AddC         1c   
      | 
| 44 |   | addcfnex 5825 | 
. . . 4
  AddC     | 
| 45 |   | vvex 4110 | 
. . . . 5
        | 
| 46 |   | snex 4112 | 
. . . . 5
   1c      | 
| 47 | 45, 46 | xpex 5116 | 
. . . 4
        1c       | 
| 48 | 44, 47 | resex 5118 | 
. . 3
    AddC         1c   
    | 
| 49 |   | 1stex 4740 | 
. . . 4
        | 
| 50 | 49 | cnvex 5103 | 
. . 3
         | 
| 51 | 48, 50 | coex 4751 | 
. 2
     AddC         1c              | 
| 52 | 43, 51 | eqeltri 2423 | 
1
                1c       |