| Step | Hyp | Ref
| Expression |
| 1 | | frecsuc.1 |
. . . . . . . 8
FRec     |
| 2 | | frecsuc.2 |
. . . . . . . 8
 Funs  |
| 3 | | frecsuc.3 |
. . . . . . . 8
   |
| 4 | | frecsuc.4 |
. . . . . . . 8
   |
| 5 | 1, 2, 3, 4 | fnfrec 6321 |
. . . . . . 7
 Nn  |
| 6 | | fnfun 5182 |
. . . . . . 7
 Nn   |
| 7 | 5, 6 | syl 15 |
. . . . . 6
   |
| 8 | | frecsuc.5 |
. . . . . . 7
 Nn  |
| 9 | 1, 2, 3, 4 | dmfrec 6317 |
. . . . . . 7
 Nn  |
| 10 | 8, 9 | eleqtrrd 2430 |
. . . . . 6
   |
| 11 | | funfvop 5401 |
. . . . . 6
    
       |
| 12 | 7, 10, 11 | syl2anc 642 |
. . . . 5
          |
| 13 | | eqid 2353 |
. . . . . 6
 1c
 1c |
| 14 | | peano2 4404 |
. . . . . . . 8
 Nn 
1c
Nn  |
| 15 | 8, 14 | syl 15 |
. . . . . . 7
 
1c
Nn  |
| 16 | | addceq1 4384 |
. . . . . . . . 9
  1c  1c  |
| 17 | 16 | eqeq2d 2364 |
. . . . . . . 8
 
 1c  1c   |
| 18 | | eqeq1 2359 |
. . . . . . . 8
  1c  
1c
 1c
 1c   |
| 19 | | mptv 5719 |
. . . . . . . 8
  1c      1c  |
| 20 | 17, 18, 19 | brabg 4707 |
. . . . . . 7
  Nn  1c Nn     1c   1c 
1c
 1c   |
| 21 | 8, 15, 20 | syl2anc 642 |
. . . . . 6
     1c   1c 
1c
 1c   |
| 22 | 13, 21 | mpbiri 224 |
. . . . 5
    1c  
1c  |
| 23 | | elfunsi 5832 |
. . . . . . . 8
 Funs   |
| 24 | 2, 23 | syl 15 |
. . . . . . 7
   |
| 25 | 3 | snssd 3854 |
. . . . . . . . 9
     |
| 26 | 4, 25 | unssd 3440 |
. . . . . . . 8
       |
| 27 | 1 | frecxpg 6316 |
. . . . . . . . . . . 12
 Funs Nn        |
| 28 | 2, 27 | syl 15 |
. . . . . . . . . . 11

Nn        |
| 29 | | rnss 4960 |
. . . . . . . . . . 11

Nn      Nn        |
| 30 | 28, 29 | syl 15 |
. . . . . . . . . 10
 Nn        |
| 31 | | rnxpss 5054 |
. . . . . . . . . 10
Nn           |
| 32 | 30, 31 | syl6ss 3285 |
. . . . . . . . 9
       |
| 33 | | fvelrn 5414 |
. . . . . . . . . 10
         |
| 34 | 7, 10, 33 | syl2anc 642 |
. . . . . . . . 9
    
  |
| 35 | 32, 34 | sseldd 3275 |
. . . . . . . 8
    
      |
| 36 | 26, 35 | sseldd 3275 |
. . . . . . 7
    
  |
| 37 | | funfvop 5401 |
. . . . . . 7
      
                 |
| 38 | 24, 36, 37 | syl2anc 642 |
. . . . . 6
                  |
| 39 | | df-br 4641 |
. . . . . 6
                                |
| 40 | 38, 39 | sylibr 203 |
. . . . 5
                 |
| 41 | | breq1 4643 |
. . . . . . 7
         PProd    1c 
   
1c                 PProd   
1c      1c             |
| 42 | | qrpprod 5837 |
. . . . . . 7
  
     PProd    1c 
   
1c             
1c   1c                  |
| 43 | 41, 42 | syl6bb 252 |
. . . . . 6
         PProd    1c 
   
1c             
1c   1c                   |
| 44 | 43 | rspcev 2956 |
. . . . 5
            
1c   1c                 
PProd  

1c      1c            |
| 45 | 12, 22, 40, 44 | syl12anc 1180 |
. . . 4
  PProd  

1c      1c            |
| 46 | 45 | olcd 382 |
. . 3
    1c
          0c    PProd   
1c      1c             |
| 47 | | snex 4112 |
. . . 4
 0c    |
| 48 | | csucex 6260 |
. . . . 5
  1c  |
| 49 | | pprodexg 5838 |
. . . . 5
   
1c Funs PProd    1c 
   |
| 50 | 48, 2, 49 | sylancr 644 |
. . . 4
 PProd  

1c  
  |
| 51 | | df-frec 6311 |
. . . . . 6
FRec   
Clos1   0c    PProd   
1c     |
| 52 | 1, 51 | eqtri 2373 |
. . . . 5
Clos1
  0c    PProd    1c 
   |
| 53 | 52 | clos1basesucg 5885 |
. . . 4
   0c   PProd   
1c  
    1c
            1c           0c    PProd   
1c      1c              |
| 54 | 47, 50, 53 | sylancr 644 |
. . 3
    1c
            1c           0c    PProd   
1c      1c              |
| 55 | 46, 54 | mpbird 223 |
. 2
   1c            |
| 56 | | fnopfvb 5360 |
. . 3
  Nn  1c Nn     
1c           1c             |
| 57 | 5, 15, 56 | syl2anc 642 |
. 2
     
1c           1c             |
| 58 | 55, 57 | mpbird 223 |
1
     1c           |