| 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  |