| Step | Hyp | Ref
 | Expression | 
| 1 |   | ncaddccl 6145 | 
. . 3
        NC       NC               NC   | 
| 2 | 1 | 3adant1 973 | 
. 2
        NC       NC       NC               NC   | 
| 3 |   | elncs 6120 | 
. . 3
             NC            
  Nc    | 
| 4 |   | vex 2863 | 
. . . . . . 7
        | 
| 5 | 4 | ncid 6124 | 
. . . . . 6
      Nc   | 
| 6 |   | eleq2 2414 | 
. . . . . 6
             Nc                        Nc     | 
| 7 | 5, 6 | mpbiri 224 | 
. . . . 5
             Nc                  | 
| 8 |   | eladdc 4399 | 
. . . . . 6
              
 
                                           | 
| 9 |   | ncseqnc 6129 | 
. . . . . . . . . 10
       NC        Nc             | 
| 10 |   | ncseqnc 6129 | 
. . . . . . . . . 10
       NC        Nc             | 
| 11 | 9, 10 | bi2anan9 843 | 
. . . . . . . . 9
        NC       NC           Nc         Nc                
       | 
| 12 | 11 | 3adant1 973 | 
. . . . . . . 8
        NC       NC       NC           Nc         Nc                
       | 
| 13 |   | elncs 6120 | 
. . . . . . . . . . . 12
       NC          Nc    | 
| 14 |   | vex 2863 | 
. . . . . . . . . . . . . . . . 17
        | 
| 15 |   | vex 2863 | 
. . . . . . . . . . . . . . . . 17
        | 
| 16 | 14, 15 | ncdisjun 6137 | 
. . . . . . . . . . . . . . . 16
              
  Nc          
  Nc     Nc     | 
| 17 | 16 | oveq2d 5539 | 
. . . . . . . . . . . . . . 15
              
    Nc  
·c Nc              Nc   ·c   Nc     Nc      | 
| 18 |   | xpdisj2 5049 | 
. . . . . . . . . . . . . . . . 17
              
     
                     | 
| 19 | 4, 14 | xpex 5116 | 
. . . . . . . . . . . . . . . . . 18
              | 
| 20 | 4, 15 | xpex 5116 | 
. . . . . . . . . . . . . . . . . 18
              | 
| 21 | 19, 20 | ncdisjun 6137 | 
. . . . . . . . . . . . . . . . 17
                             Nc    
                    Nc           Nc           | 
| 22 | 18, 21 | syl 15 | 
. . . . . . . . . . . . . . . 16
              
  Nc         
               Nc           Nc   
       | 
| 23 | 14, 15 | unex 4107 | 
. . . . . . . . . . . . . . . . . 18
              | 
| 24 | 4, 23 | mucnc 6132 | 
. . . . . . . . . . . . . . . . 17
    Nc   ·c Nc            Nc   
           | 
| 25 |   | xpundi 4833 | 
. . . . . . . . . . . . . . . . . 18
               
     
                | 
| 26 | 25 | nceqi 6110 | 
. . . . . . . . . . . . . . . . 17
  Nc                 Nc                     | 
| 27 | 24, 26 | eqtri 2373 | 
. . . . . . . . . . . . . . . 16
    Nc   ·c Nc            Nc                     | 
| 28 | 4, 14 | mucnc 6132 | 
. . . . . . . . . . . . . . . . 17
    Nc   ·c Nc      Nc   
     | 
| 29 | 4, 15 | mucnc 6132 | 
. . . . . . . . . . . . . . . . 17
    Nc   ·c Nc      Nc   
     | 
| 30 | 28, 29 | addceq12i 4389 | 
. . . . . . . . . . . . . . . 16
     Nc  
·c Nc        Nc   ·c Nc         Nc           Nc   
      | 
| 31 | 22, 27, 30 | 3eqtr4g 2410 | 
. . . . . . . . . . . . . . 15
              
    Nc  
·c Nc               Nc   ·c Nc       
Nc   ·c Nc      | 
| 32 | 17, 31 | eqtr3d 2387 | 
. . . . . . . . . . . . . 14
              
    Nc  
·c   Nc     Nc          Nc   ·c Nc        Nc  
·c Nc      | 
| 33 |   | oveq1 5531 | 
. . . . . . . . . . . . . . 15
       Nc       
·c   Nc     Nc         Nc  
·c   Nc     Nc      | 
| 34 |   | oveq1 5531 | 
. . . . . . . . . . . . . . . 16
       Nc       
·c Nc     
  Nc   ·c Nc     | 
| 35 |   | oveq1 5531 | 
. . . . . . . . . . . . . . . 16
       Nc       
·c Nc     
  Nc   ·c Nc     | 
| 36 | 34, 35 | addceq12d 4392 | 
. . . . . . . . . . . . . . 15
       Nc         ·c Nc         ·c Nc          Nc   ·c Nc       
Nc   ·c Nc      | 
| 37 | 33, 36 | eqeq12d 2367 | 
. . . . . . . . . . . . . 14
       Nc         ·c   Nc     Nc           ·c Nc        
·c Nc    
 
  Nc   ·c   Nc     Nc          Nc   ·c Nc        Nc  
·c Nc       | 
| 38 | 32, 37 | syl5ibr 212 | 
. . . . . . . . . . . . 13
       Nc                      
·c   Nc     Nc          
·c Nc        
·c Nc       | 
| 39 | 38 | exlimiv 1634 | 
. . . . . . . . . . . 12
       
  Nc                 
     ·c   Nc     Nc           ·c Nc        
·c Nc       | 
| 40 | 13, 39 | sylbi 187 | 
. . . . . . . . . . 11
       NC                    
·c   Nc     Nc          
·c Nc        
·c Nc       | 
| 41 | 40 | adantrd 454 | 
. . . . . . . . . 10
       NC                                    
·c   Nc     Nc          
·c Nc        
·c Nc       | 
| 42 |   | addceq12 4386 | 
. . . . . . . . . . . . 13
        Nc         Nc               
  Nc     Nc     | 
| 43 | 42 | oveq2d 5539 | 
. . . . . . . . . . . 12
        Nc         Nc        
·c         
     ·c   Nc     Nc      | 
| 44 |   | oveq2 5532 | 
. . . . . . . . . . . . . 14
       Nc       
·c         ·c Nc     | 
| 45 | 44 | adantr 451 | 
. . . . . . . . . . . . 13
        Nc         Nc        
·c         ·c Nc     | 
| 46 |   | oveq2 5532 | 
. . . . . . . . . . . . . 14
       Nc       
·c         ·c Nc     | 
| 47 | 46 | adantl 452 | 
. . . . . . . . . . . . 13
        Nc         Nc        
·c         ·c Nc     | 
| 48 | 45, 47 | addceq12d 4392 | 
. . . . . . . . . . . 12
        Nc         Nc         
·c         ·c          
·c Nc        
·c Nc      | 
| 49 | 43, 48 | eqeq12d 2367 | 
. . . . . . . . . . 11
        Nc         Nc         
·c         
     
·c         ·c          ·c   Nc     Nc           ·c Nc        
·c Nc       | 
| 50 | 49 | imbi2d 307 | 
. . . . . . . . . 10
        Nc         Nc                    
              
     ·c                ·c   
     ·c                   
                
     ·c   Nc     Nc           ·c Nc        
·c Nc        | 
| 51 | 41, 50 | syl5ibrcom 213 | 
. . . . . . . . 9
       NC         Nc        
Nc                 
                
     ·c                ·c   
     ·c        | 
| 52 | 51 | 3ad2ant1 976 | 
. . . . . . . 8
        NC       NC       NC           Nc         Nc                                       
·c         
     
·c         ·c        | 
| 53 | 12, 52 | sylbird 226 | 
. . . . . . 7
        NC       NC       NC                  
                                      
·c         
     
·c         ·c        | 
| 54 | 53 | rexlimdvv 2745 | 
. . . . . 6
        NC       NC       NC          
                                         
·c         
     
·c         ·c       | 
| 55 | 8, 54 | syl5bi 208 | 
. . . . 5
        NC       NC       NC                 
     ·c                ·c   
     ·c       | 
| 56 | 7, 55 | syl5 28 | 
. . . 4
        NC       NC       NC                Nc       
·c         
     
·c         ·c       | 
| 57 | 56 | exlimdv 1636 | 
. . 3
        NC       NC       NC                 
Nc        ·c                ·c        
·c       | 
| 58 | 3, 57 | syl5bi 208 | 
. 2
        NC       NC       NC                NC     
·c         
     
·c         ·c       | 
| 59 | 2, 58 | mpd 14 | 
1
        NC       NC       NC        ·c                ·c        
·c      |