| Step | Hyp | Ref
| Expression |
| 1 | | fucpropd.1 |
. . . . 5
 
f   
f     |
| 2 | | fucpropd.2 |
. . . . 5
 compf  compf    |
| 3 | | fucpropd.3 |
. . . . 5
 
f   
f     |
| 4 | | fucpropd.4 |
. . . . 5
 compf  compf    |
| 5 | | fucpropd.a |
. . . . 5
   |
| 6 | | fucpropd.b |
. . . . 5
   |
| 7 | | fucpropd.c |
. . . . 5
   |
| 8 | | fucpropd.d |
. . . . 5
   |
| 9 | 1, 2, 3, 4, 5, 6, 7, 8 | funcpropd 16560 |
. . . 4
       |
| 10 | 9 | opeq2d 4409 |
. . 3
      
              |
| 11 | 1, 2, 3, 4, 5, 6, 7, 8 | natpropd 16636 |
. . . 4
  Nat   Nat    |
| 12 | 11 | opeq2d 4409 |
. . 3
     
 Nat  
      Nat     |
| 13 | 9 | sqxpeqd 5141 |
. . . . 5
               |
| 14 | 9 | adantr 481 |
. . . . 5
 
             |
| 15 | | nfv 1843 |
. . . . . 6
     
         |
| 16 | | nfcsb1v 3549 |
. . . . . . 7
        ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                     |
| 17 | 16 | a1i 11 |
. . . . . 6
 
      
            ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 18 | | fvexd 6203 |
. . . . . 6
 
      
          |
| 19 | | nfv 1843 |
. . . . . . . 8
          
          |
| 20 | | nfcsb1v 3549 |
. . . . . . . . 9
        ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                     |
| 21 | 20 | a1i 11 |
. . . . . . . 8
     
       
             ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 22 | | fvexd 6203 |
. . . . . . . 8
     
       
           |
| 23 | 11 | ad3antrrr 766 |
. . . . . . . . . . 11
          
               Nat   Nat    |
| 24 | 23 | oveqd 6667 |
. . . . . . . . . 10
          
                 Nat       Nat      |
| 25 | 23 | oveqdr 6674 |
. . . . . . . . . 10
           
                 Nat    
   Nat       Nat      |
| 26 | 1 | homfeqbas 16356 |
. . . . . . . . . . . 12
           |
| 27 | 26 | ad4antr 768 |
. . . . . . . . . . 11
           
                  Nat       Nat                |
| 28 | | eqid 2622 |
. . . . . . . . . . . 12
         |
| 29 | | eqid 2622 |
. . . . . . . . . . . 12
       |
| 30 | | eqid 2622 |
. . . . . . . . . . . 12
comp  comp   |
| 31 | | eqid 2622 |
. . . . . . . . . . . 12
comp  comp   |
| 32 | 3 | ad5antr 770 |
. . . . . . . . . . . 12
     
      
                  Nat       Nat            f    f     |
| 33 | 4 | ad5antr 770 |
. . . . . . . . . . . 12
     
      
                  Nat       Nat           compf  compf    |
| 34 | | eqid 2622 |
. . . . . . . . . . . . . 14
         |
| 35 | | relfunc 16522 |
. . . . . . . . . . . . . . 15
   |
| 36 | | simpllr 799 |
. . . . . . . . . . . . . . . 16
           
                  Nat       Nat            |
| 37 | | simp-4r 807 |
. . . . . . . . . . . . . . . . . 18
           
                  Nat       Nat        
         |
| 38 | 37 | simpld 475 |
. . . . . . . . . . . . . . . . 17
           
                  Nat       Nat              |
| 39 | | xp1st 7198 |
. . . . . . . . . . . . . . . . 17
               |
| 40 | 38, 39 | syl 17 |
. . . . . . . . . . . . . . . 16
           
                  Nat       Nat              |
| 41 | 36, 40 | eqeltrd 2701 |
. . . . . . . . . . . . . . 15
           
                  Nat       Nat          |
| 42 | | 1st2ndbr 7217 |
. . . . . . . . . . . . . . 15
            
        |
| 43 | 35, 41, 42 | sylancr 695 |
. . . . . . . . . . . . . 14
           
                  Nat       Nat           
        |
| 44 | 34, 28, 43 | funcf1 16526 |
. . . . . . . . . . . . 13
           
                  Nat       Nat                        |
| 45 | 44 | ffvelrnda 6359 |
. . . . . . . . . . . 12
     
      
                  Nat       Nat                         |
| 46 | | simplr 792 |
. . . . . . . . . . . . . . . 16
           
                  Nat       Nat            |
| 47 | | xp2nd 7199 |
. . . . . . . . . . . . . . . . 17
               |
| 48 | 38, 47 | syl 17 |
. . . . . . . . . . . . . . . 16
           
                  Nat       Nat              |
| 49 | 46, 48 | eqeltrd 2701 |
. . . . . . . . . . . . . . 15
           
                  Nat       Nat          |
| 50 | | 1st2ndbr 7217 |
. . . . . . . . . . . . . . 15
            
        |
| 51 | 35, 49, 50 | sylancr 695 |
. . . . . . . . . . . . . 14
           
                  Nat       Nat           
        |
| 52 | 34, 28, 51 | funcf1 16526 |
. . . . . . . . . . . . 13
           
                  Nat       Nat                        |
| 53 | 52 | ffvelrnda 6359 |
. . . . . . . . . . . 12
     
      
                  Nat       Nat                         |
| 54 | 37 | simprd 479 |
. . . . . . . . . . . . . . 15
           
                  Nat       Nat          |
| 55 | | 1st2ndbr 7217 |
. . . . . . . . . . . . . . 15
            
        |
| 56 | 35, 54, 55 | sylancr 695 |
. . . . . . . . . . . . . 14
           
                  Nat       Nat           
        |
| 57 | 34, 28, 56 | funcf1 16526 |
. . . . . . . . . . . . 13
           
                  Nat       Nat                        |
| 58 | 57 | ffvelrnda 6359 |
. . . . . . . . . . . 12
     
      
                  Nat       Nat                         |
| 59 | | eqid 2622 |
. . . . . . . . . . . . 13
 Nat   Nat   |
| 60 | | simplrr 801 |
. . . . . . . . . . . . . 14
     
      
                  Nat       Nat              Nat      |
| 61 | 59, 60 | nat1st2nd 16611 |
. . . . . . . . . . . . 13
     
      
                  Nat       Nat                         Nat                 |
| 62 | | simpr 477 |
. . . . . . . . . . . . 13
     
      
                  Nat       Nat                 |
| 63 | 59, 61, 34, 29, 62 | natcl 16613 |
. . . . . . . . . . . 12
     
      
                  Nat       Nat                                        |
| 64 | | simplrl 800 |
. . . . . . . . . . . . . 14
     
      
                  Nat       Nat              Nat      |
| 65 | 59, 64 | nat1st2nd 16611 |
. . . . . . . . . . . . 13
     
      
                  Nat       Nat                         Nat                 |
| 66 | 59, 65, 34, 29, 62 | natcl 16613 |
. . . . . . . . . . . 12
     
      
                  Nat       Nat                                        |
| 67 | 28, 29, 30, 31, 32, 33, 45, 53, 58, 63, 66 | comfeqval 16368 |
. . . . . . . . . . 11
     
      
                  Nat       Nat                                      comp                                             comp                    |
| 68 | 27, 67 | mpteq12dva 4732 |
. . . . . . . . . 10
           
                  Nat       Nat                                      comp                                                   comp                     |
| 69 | 24, 25, 68 | mpt2eq123dva 6716 |
. . . . . . . . 9
          
                  Nat        Nat                                    comp                        Nat        Nat                                    comp                      |
| 70 | | csbeq1a 3542 |
. . . . . . . . . 10
    
    Nat        Nat                                    comp                          ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 71 | 70 | adantl 482 |
. . . . . . . . 9
          
                  Nat        Nat                                    comp                          ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 72 | 69, 71 | eqtrd 2656 |
. . . . . . . 8
          
                  Nat        Nat                                    comp                          ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 73 | 19, 21, 22, 72 | csbiedf 3554 |
. . . . . . 7
     
       
           ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                          ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 74 | | csbeq1a 3542 |
. . . . . . . 8
    
      ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                          ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 75 | 74 | adantl 482 |
. . . . . . 7
     
       
           ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                          ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 76 | 73, 75 | eqtrd 2656 |
. . . . . 6
     
       
           ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                          ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 77 | 15, 17, 18, 76 | csbiedf 3554 |
. . . . 5
 
      
          ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                          ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      |
| 78 | 13, 14, 77 | mpt2eq123dva 6716 |
. . . 4
                 ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                                     ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                       |
| 79 | 78 | opeq2d 4409 |
. . 3
  comp                   ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                       comp  
                ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                        |
| 80 | 10, 12, 79 | tpeq123d 4283 |
. 2
       
          Nat   
 comp           
       ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                      
                 Nat   
 comp           
       ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                         |
| 81 | | eqid 2622 |
. . 3
 FuncCat   FuncCat   |
| 82 | | eqid 2622 |
. . 3
  
  |
| 83 | | eqidd 2623 |
. . 3
                 ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                                     ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                       |
| 84 | 81, 82, 59, 34, 30, 5, 7, 83 | fucval 16618 |
. 2
  FuncCat
       
          Nat   
 comp           
       ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                         |
| 85 | | eqid 2622 |
. . 3
 FuncCat   FuncCat   |
| 86 | | eqid 2622 |
. . 3
  
  |
| 87 | | eqid 2622 |
. . 3
 Nat   Nat   |
| 88 | | eqid 2622 |
. . 3
         |
| 89 | | eqidd 2623 |
. . 3
                 ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                                     ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                       |
| 90 | 85, 86, 87, 88, 31, 6, 8, 89 | fucval 16618 |
. 2
  FuncCat
       
          Nat   
 comp           
       ![]_ ]_](_urbrack.gif)       ![]_ ]_](_urbrack.gif)     Nat        Nat                                    comp                         |
| 91 | 80, 84, 90 | 3eqtr4d 2666 |
1
  FuncCat
  FuncCat    |