| Step | Hyp | Ref
 | Expression | 
| 1 |   | eqeq1 2359 | 
. . . . . 6
               
           1c       
           1c    | 
| 2 | 1 | rexbidv 2636 | 
. . . . 5
              
  Nn                1c         Nn                1c    | 
| 3 |   | neeq1 2525 | 
. . . . 5
                 
 
        | 
| 4 | 2, 3 | anbi12d 691 | 
. . . 4
                  Nn                1c                   Nn                1c             | 
| 5 |   | df-oddfin 4446 | 
. . . 4
  Oddfin           
  Nn                1c            | 
| 6 | 4, 5 | elab2g 2988 | 
. . 3
       Oddfin     
  Oddfin         Nn                1c             | 
| 7 | 6 | ibi 232 | 
. 2
       Oddfin         Nn                1c            | 
| 8 |   | addceq2 4385 | 
. . . . . . . . . . . . . 14
        
                     | 
| 9 |   | addcnul1 4453 | 
. . . . . . . . . . . . . 14
              | 
| 10 | 8, 9 | syl6eq 2401 | 
. . . . . . . . . . . . 13
        
               | 
| 11 |   | addceq1 4384 | 
. . . . . . . . . . . . 13
              
     
       1c         1c   | 
| 12 | 10, 11 | syl 15 | 
. . . . . . . . . . . 12
        
     
       1c         1c   | 
| 13 |   | addccom 4407 | 
. . . . . . . . . . . . 13
       1c     1c      | 
| 14 |   | addcnul1 4453 | 
. . . . . . . . . . . . 13
   1c          | 
| 15 | 13, 14 | eqtri 2373 | 
. . . . . . . . . . . 12
       1c      | 
| 16 | 12, 15 | syl6eq 2401 | 
. . . . . . . . . . 11
        
     
       1c       | 
| 17 | 16 | necon3i 2556 | 
. . . . . . . . . 10
              1c               | 
| 18 |   | tfinprop 4490 | 
. . . . . . . . . . 11
        Nn              Tfin     Nn           1     Tfin     | 
| 19 | 18 | simpld 445 | 
. . . . . . . . . 10
        Nn            Tfin     Nn   | 
| 20 | 17, 19 | sylan2 460 | 
. . . . . . . . 9
        Nn             
1c 
       Tfin     Nn   | 
| 21 |   | nncaddccl 4420 | 
. . . . . . . . . . . 12
        Nn       Nn               Nn   | 
| 22 | 21 | anidms 626 | 
. . . . . . . . . . 11
       Nn            
Nn   | 
| 23 |   | 1cnnc 4409 | 
. . . . . . . . . . . 12
 
1c  
Nn | 
| 24 |   | tfindi 4497 | 
. . . . . . . . . . . 12
             
Nn   1c   Nn              1c         Tfin            1c   
  Tfin   
       Tfin
1c   | 
| 25 | 23, 24 | mp3an2 1265 | 
. . . . . . . . . . 11
             
Nn           
 
1c 
       Tfin            1c   
  Tfin   
       Tfin
1c   | 
| 26 | 22, 25 | sylan 457 | 
. . . . . . . . . 10
        Nn             
1c 
       Tfin            1c   
  Tfin   
       Tfin
1c   | 
| 27 |   | addcnnul 4454 | 
. . . . . . . . . . . . 13
              1c           
        
 
1c       | 
| 28 | 27 | simpld 445 | 
. . . . . . . . . . . 12
              1c                     | 
| 29 |   | tfindi 4497 | 
. . . . . . . . . . . . 13
        Nn       Nn          
       Tfin             Tfin
    Tfin     | 
| 30 | 29 | 3anidm12 1239 | 
. . . . . . . . . . . 12
        Nn          
       Tfin             Tfin
    Tfin     | 
| 31 | 28, 30 | sylan2 460 | 
. . . . . . . . . . 11
        Nn             
1c 
       Tfin             Tfin
    Tfin     | 
| 32 |   | tfin1c 4500 | 
. . . . . . . . . . . 12
  Tfin 1c   1c | 
| 33 |   | addceq12 4386 | 
. . . . . . . . . . . 12
     Tfin
            Tfin
    Tfin   
  Tfin 1c   1c      Tfin           Tfin 1c       Tfin     Tfin      1c   | 
| 34 | 32, 33 | mpan2 652 | 
. . . . . . . . . . 11
    Tfin   
      
  Tfin     Tfin        Tfin   
       Tfin
1c 
     Tfin     Tfin   
 
1c   | 
| 35 | 31, 34 | syl 15 | 
. . . . . . . . . 10
        Nn             
1c 
         Tfin           Tfin 1c       Tfin     Tfin      1c   | 
| 36 | 26, 35 | eqtrd 2385 | 
. . . . . . . . 9
        Nn             
1c 
       Tfin            1c   
   Tfin     Tfin      1c   | 
| 37 |   | addceq12 4386 | 
. . . . . . . . . . . . 13
        Tfin         Tfin   
              Tfin     Tfin     | 
| 38 | 37 | anidms 626 | 
. . . . . . . . . . . 12
       Tfin              
  Tfin     Tfin     | 
| 39 |   | addceq1 4384 | 
. . . . . . . . . . . 12
               Tfin     Tfin                
1c 
     Tfin     Tfin   
 
1c   | 
| 40 | 38, 39 | syl 15 | 
. . . . . . . . . . 11
       Tfin             
 
1c 
     Tfin     Tfin   
 
1c   | 
| 41 | 40 | eqeq2d 2364 | 
. . . . . . . . . 10
       Tfin       Tfin    
       1c               1c    Tfin            1c   
   Tfin     Tfin      1c    | 
| 42 | 41 | rspcev 2956 | 
. . . . . . . . 9
     Tfin
    Nn   Tfin            1c       Tfin
    Tfin   
 
1c         
Nn Tfin
           1c            
 
1c   | 
| 43 | 20, 36, 42 | syl2anc 642 | 
. . . . . . . 8
        Nn             
1c 
            Nn Tfin            1c   
           1c   | 
| 44 |   | peano2 4404 | 
. . . . . . . . . 10
             Nn           
 
1c 
  Nn   | 
| 45 | 22, 44 | syl 15 | 
. . . . . . . . 9
       Nn           
 
1c 
  Nn   | 
| 46 |   | tfinnnul 4491 | 
. . . . . . . . 9
            
 
1c 
  Nn             
1c 
       Tfin            1c       | 
| 47 | 45, 46 | sylan 457 | 
. . . . . . . 8
        Nn             
1c 
       Tfin            1c       | 
| 48 | 43, 47 | jca 518 | 
. . . . . . 7
        Nn             
1c 
             Nn Tfin            1c               1c    Tfin    
       1c        | 
| 49 |   | tfinex 4486 | 
. . . . . . . 8
  Tfin            1c      | 
| 50 |   | eqeq1 2359 | 
. . . . . . . . . 10
       Tfin    
       1c                   
1c 
 
Tfin            1c               1c    | 
| 51 | 50 | rexbidv 2636 | 
. . . . . . . . 9
       Tfin    
       1c         
Nn                1c         Nn Tfin            1c   
           1c    | 
| 52 |   | neeq1 2525 | 
. . . . . . . . 9
       Tfin    
       1c          
 
Tfin            1c        | 
| 53 | 51, 52 | anbi12d 691 | 
. . . . . . . 8
       Tfin    
       1c        
  Nn                1c                   Nn Tfin            1c   
           1c    Tfin            1c         | 
| 54 |   | df-oddfin 4446 | 
. . . . . . . 8
  Oddfin           
  Nn                1c            | 
| 55 | 49, 53, 54 | elab2 2989 | 
. . . . . . 7
    Tfin            1c    Oddfin         Nn Tfin            1c   
           1c    Tfin            1c        | 
| 56 | 48, 55 | sylibr 203 | 
. . . . . 6
        Nn             
1c 
       Tfin            1c   
Oddfin   | 
| 57 | 56 | ex 423 | 
. . . . 5
       Nn              
1c 
      Tfin            1c    Oddfin    | 
| 58 |   | neeq1 2525 | 
. . . . . . . 8
                 
1c 
        
 
           1c        | 
| 59 |   | tfineq 4489 | 
. . . . . . . . 9
                 
1c 
  Tfin    
Tfin            1c   | 
| 60 | 59 | eleq1d 2419 | 
. . . . . . . 8
                 
1c 
    Tfin    
Oddfin   Tfin            1c    Oddfin    | 
| 61 | 58, 60 | imbi12d 311 | 
. . . . . . 7
                 
1c 
     
      Tfin    
Oddfin                
1c 
      Tfin            1c    Oddfin     | 
| 62 | 61 | biimprd 214 | 
. . . . . 6
                 
1c 
            
 
1c 
      Tfin            1c    Oddfin              Tfin     Oddfin     | 
| 63 | 62 | com12 27 | 
. . . . 5
            
 
1c 
      Tfin            1c    Oddfin                     1c          
  Tfin    
Oddfin     | 
| 64 | 57, 63 | syl 15 | 
. . . 4
       Nn                   1c          
  Tfin    
Oddfin     | 
| 65 | 64 | rexlimiv 2733 | 
. . 3
       
Nn                1c             Tfin     Oddfin    | 
| 66 | 65 | imp 418 | 
. 2
      
  Nn                1c             Tfin     Oddfin   | 
| 67 | 7, 66 | syl 15 | 
1
       Oddfin   Tfin    
Oddfin   |