| Step | Hyp | Ref
| Expression |
| 1 | | ccatcl 13359 |
. . . . 5
  Word
Word   ++  Word   |
| 2 | 1 | adantr 481 |
. . . 4
   Word
Word      
           
 ++  Word   |
| 3 | | elfz0fzfz0 12444 |
. . . . 5
     
          
      |
| 4 | 3 | adantl 482 |
. . . 4
   Word
Word      
           
      |
| 5 | | elfzuz2 12346 |
. . . . . . . . 9
           |
| 6 | 5 | adantl 482 |
. . . . . . . 8
   Word
Word      
      |
| 7 | | fzss1 12380 |
. . . . . . . 8
    
                      |
| 8 | 6, 7 | syl 17 |
. . . . . . 7
   Word
Word      
                      |
| 9 | | ccatlen 13360 |
. . . . . . . . . 10
  Word
Word      ++               |
| 10 | | pfxccatin12.l |
. . . . . . . . . . . 12
     |
| 11 | 10 | eqcomi 2631 |
. . . . . . . . . . 11
     |
| 12 | 11 | oveq1i 6660 |
. . . . . . . . . 10
                 |
| 13 | 9, 12 | syl6eq 2672 |
. . . . . . . . 9
  Word
Word      ++           |
| 14 | 13 | adantr 481 |
. . . . . . . 8
   Word
Word      
    ++           |
| 15 | 14 | oveq2d 6666 |
. . . . . . 7
   Word
Word      
       ++                |
| 16 | 8, 15 | sseqtr4d 3642 |
. . . . . 6
   Word
Word      
                 ++      |
| 17 | 16 | sseld 3602 |
. . . . 5
   Word
Word      
    
     
       ++       |
| 18 | 17 | impr 649 |
. . . 4
   Word
Word      
           
       ++      |
| 19 | | swrdvalfn 13426 |
. . . 4
   ++  Word    
       ++       ++  substr      ..^     |
| 20 | 2, 4, 18, 19 | syl3anc 1326 |
. . 3
   Word
Word      
           
  ++  substr      ..^     |
| 21 | | swrdcl 13419 |
. . . . . . 7
 Word  substr     Word   |
| 22 | | pfxcl 41386 |
. . . . . . 7
 Word  prefix    Word   |
| 23 | 21, 22 | anim12i 590 |
. . . . . 6
  Word
Word    substr     Word  prefix    Word    |
| 24 | 23 | adantr 481 |
. . . . 5
   Word
Word      
           
  substr     Word 
prefix    Word    |
| 25 | | ccatvalfn 13365 |
. . . . 5
   substr     Word  prefix    Word    substr     ++  prefix      ..^     substr  
       prefix         |
| 26 | 24, 25 | syl 17 |
. . . 4
   Word
Word      
           
  substr     ++  prefix 
    ..^     substr          prefix         |
| 27 | | simpll 790 |
. . . . . . . . 9
   Word
Word      
           
Word   |
| 28 | | simprl 794 |
. . . . . . . . 9
   Word
Word      
           
      |
| 29 | | lencl 13324 |
. . . . . . . . . . 11
 Word       |
| 30 | | elnn0uz 11725 |
. . . . . . . . . . . . 13
               |
| 31 | | eluzfz2 12349 |
. . . . . . . . . . . . 13
                       |
| 32 | 30, 31 | sylbi 207 |
. . . . . . . . . . . 12
    
              |
| 33 | 10, 32 | syl5eqel 2705 |
. . . . . . . . . . 11
    
          |
| 34 | 29, 33 | syl 17 |
. . . . . . . . . 10
 Word           |
| 35 | 34 | ad2antrr 762 |
. . . . . . . . 9
   Word
Word      
           
          |
| 36 | | swrdlen 13423 |
. . . . . . . . 9
  Word
   
             substr          |
| 37 | 27, 28, 35, 36 | syl3anc 1326 |
. . . . . . . 8
   Word
Word      
           
    substr          |
| 38 | | simplr 792 |
. . . . . . . . 9
   Word
Word      
           
Word   |
| 39 | | lencl 13324 |
. . . . . . . . . . . . 13
 Word       |
| 40 | 39 | nn0zd 11480 |
. . . . . . . . . . . 12
 Word       |
| 41 | 40 | adantl 482 |
. . . . . . . . . . 11
  Word
Word        |
| 42 | | simpr 477 |
. . . . . . . . . . 11
     
          
            |
| 43 | 41, 42 | anim12i 590 |
. . . . . . . . . 10
   Word
Word      
           
        
         |
| 44 | | elfzmlbp 12450 |
. . . . . . . . . 10
     
                       |
| 45 | 43, 44 | syl 17 |
. . . . . . . . 9
   Word
Word      
           
            |
| 46 | | pfxlen 41391 |
. . . . . . . . 9
  Word 
              prefix         |
| 47 | 38, 45, 46 | syl2anc 693 |
. . . . . . . 8
   Word
Word      
           
    prefix         |
| 48 | 37, 47 | oveq12d 6668 |
. . . . . . 7
   Word
Word      
           
     substr          prefix              |
| 49 | | elfz2nn0 12431 |
. . . . . . . . . . 11
    

   |
| 50 | | nn0cn 11302 |
. . . . . . . . . . . . . . . . 17

  |
| 51 | 50 | adantl 482 |
. . . . . . . . . . . . . . . 16
 

  |
| 52 | 51 | adantl 482 |
. . . . . . . . . . . . . . 15
  
 
  |
| 53 | | nn0cn 11302 |
. . . . . . . . . . . . . . . 16

  |
| 54 | 53 | ad2antrl 764 |
. . . . . . . . . . . . . . 15
  
 
  |
| 55 | | zcn 11382 |
. . . . . . . . . . . . . . . 16
   |
| 56 | 55 | adantr 481 |
. . . . . . . . . . . . . . 15
  
 
  |
| 57 | 52, 54, 56 | 3jca 1242 |
. . . . . . . . . . . . . 14
  
 
    |
| 58 | 57 | ex 450 |
. . . . . . . . . . . . 13
    
    |
| 59 | | elfzelz 12342 |
. . . . . . . . . . . . 13
    
     
  |
| 60 | 58, 59 | syl11 33 |
. . . . . . . . . . . 12
 
            
    |
| 61 | 60 | 3adant3 1081 |
. . . . . . . . . . 11
 
 
          
    |
| 62 | 49, 61 | sylbi 207 |
. . . . . . . . . 10
     
          
    |
| 63 | 62 | imp 445 |
. . . . . . . . 9
     
           
   |
| 64 | 63 | adantl 482 |
. . . . . . . 8
   Word
Word      
           
    |
| 65 | | npncan3 10319 |
. . . . . . . 8
 
           |
| 66 | 64, 65 | syl 17 |
. . . . . . 7
   Word
Word      
           
 
        |
| 67 | 48, 66 | eqtr2d 2657 |
. . . . . 6
   Word
Word      
           
       substr          prefix        |
| 68 | 67 | oveq2d 6666 |
. . . . 5
   Word
Word      
           
 ..^    ..^     substr          prefix         |
| 69 | 68 | fneq2d 5982 |
. . . 4
   Word
Word      
           
   substr
    ++  prefix      ..^     substr     ++  prefix      ..^     substr  
       prefix          |
| 70 | 26, 69 | mpbird 247 |
. . 3
   Word
Word      
           
  substr     ++  prefix 
    ..^     |
| 71 | | simprl 794 |
. . . . . 6
   ..^      Word Word 
    
             ..^       Word
Word      
              |
| 72 | | simpr 477 |
. . . . . . . 8
    Word Word 
    
             ..^   
 ..^     |
| 73 | 72 | anim2i 593 |
. . . . . . 7
   ..^      Word Word 
    
             ..^       ..^    ..^      |
| 74 | 73 | ancomd 467 |
. . . . . 6
   ..^      Word Word 
    
             ..^       ..^    ..^      |
| 75 | 10 | swrdccatin12lem3 13490 |
. . . . . 6
   Word
Word      
           
   ..^    ..^   
   ++  substr          substr           |
| 76 | 71, 74, 75 | sylc 65 |
. . . . 5
   ..^      Word Word 
    
             ..^        ++  substr          substr          |
| 77 | 24 | ad2antrl 764 |
. . . . . . 7
   ..^      Word Word 
    
             ..^       substr
    Word  prefix    Word    |
| 78 | | simpl 473 |
. . . . . . . 8
   ..^      Word Word 
    
             ..^      ..^     |
| 79 | | nn0fz0 12437 |
. . . . . . . . . . . . . . 15
                   |
| 80 | 29, 79 | sylib 208 |
. . . . . . . . . . . . . 14
 Word               |
| 81 | 10, 80 | syl5eqel 2705 |
. . . . . . . . . . . . 13
 Word           |
| 82 | 81 | ad2antrr 762 |
. . . . . . . . . . . 12
   Word
Word      
           
          |
| 83 | 27, 28, 82 | 3jca 1242 |
. . . . . . . . . . 11
   Word
Word      
           
 Word    
           |
| 84 | 83 | ad2antrl 764 |
. . . . . . . . . 10
   ..^      Word Word 
    
             ..^     
Word    
           |
| 85 | 84, 36 | syl 17 |
. . . . . . . . 9
   ..^      Word Word 
    
             ..^         substr          |
| 86 | 85 | oveq2d 6666 |
. . . . . . . 8
   ..^      Word Word 
    
             ..^      ..^    substr        ..^     |
| 87 | 78, 86 | eleqtrrd 2704 |
. . . . . . 7
   ..^      Word Word 
    
             ..^      ..^    substr         |
| 88 | | df-3an 1039 |
. . . . . . 7
   substr     Word  prefix    Word  ..^    substr           substr     Word 
prefix    Word   ..^    substr          |
| 89 | 77, 87, 88 | sylanbrc 698 |
. . . . . 6
   ..^      Word Word 
    
             ..^       substr
    Word  prefix    Word  ..^    substr          |
| 90 | | ccatval1 13361 |
. . . . . 6
   substr     Word  prefix    Word  ..^    substr       
   substr
    ++  prefix          substr          |
| 91 | 89, 90 | syl 17 |
. . . . 5
   ..^      Word Word 
    
             ..^        substr     ++  prefix          substr          |
| 92 | 76, 91 | eqtr4d 2659 |
. . . 4
   ..^      Word Word 
    
             ..^        ++  substr           substr     ++  prefix 
        |
| 93 | | simprl 794 |
. . . . . 6
   ..^      Word Word  
   
             ..^    
 
Word Word  
   
              |
| 94 | 72 | anim2i 593 |
. . . . . . 7
   ..^      Word Word  
   
             ..^    

 ..^    ..^      |
| 95 | 94 | ancomd 467 |
. . . . . 6
   ..^      Word Word  
   
             ..^    
  ..^    ..^      |
| 96 | 10 | pfxccatin12lem2 41424 |
. . . . . 6
   Word
Word      
           
   ..^  
 ..^       ++  substr          prefix           substr           |
| 97 | 93, 95, 96 | sylc 65 |
. . . . 5
   ..^      Word Word  
   
             ..^    
   ++  substr          prefix 
         substr          |
| 98 | 24 | ad2antrl 764 |
. . . . . . 7
   ..^      Word Word  
   
             ..^    
  substr     Word 
prefix    Word    |
| 99 | | elfzuz 12338 |
. . . . . . . . . . . . 13
    
     
      |
| 100 | | eluzelz 11697 |
. . . . . . . . . . . . . 14
    
  |
| 101 | | simpll 790 |
. . . . . . . . . . . . . . . . . . 19
   
   |
| 102 | | simplr 792 |
. . . . . . . . . . . . . . . . . . 19
   
   |
| 103 | | simpr 477 |
. . . . . . . . . . . . . . . . . . 19
   
   |
| 104 | 101, 102,
103 | 3jca 1242 |
. . . . . . . . . . . . . . . . . 18
   
 
   |
| 105 | 104 | ex 450 |
. . . . . . . . . . . . . . . . 17
 
  
    |
| 106 | 105 | ancoms 469 |
. . . . . . . . . . . . . . . 16
 
  
    |
| 107 | 106 | 3adant3 1081 |
. . . . . . . . . . . . . . 15
 
 

    |
| 108 | 49, 107 | sylbi 207 |
. . . . . . . . . . . . . 14
     

    |
| 109 | 100, 108 | syl5com 31 |
. . . . . . . . . . . . 13
    
    

    |
| 110 | 99, 109 | syl 17 |
. . . . . . . . . . . 12
    
     
    

    |
| 111 | 110 | impcom 446 |
. . . . . . . . . . 11
     
           
   |
| 112 | 111 | adantl 482 |
. . . . . . . . . 10
   Word
Word      
           

   |
| 113 | 112 | ad2antrl 764 |
. . . . . . . . 9
   ..^      Word Word  
   
             ..^    

   |
| 114 | | swrdccatin12lem1 13484 |
. . . . . . . . 9
 
    ..^  
 ..^       ..^          |
| 115 | 113, 95, 114 | sylc 65 |
. . . . . . . 8
   ..^      Word Word  
   
             ..^    
   ..^         |
| 116 | 27, 28, 82, 36 | syl3anc 1326 |
. . . . . . . . . 10
   Word
Word      
           
    substr          |
| 117 | | simpr 477 |
. . . . . . . . . . . . . . . . 17
  Word
Word  Word   |
| 118 | 117 | adantl 482 |
. . . . . . . . . . . . . . . 16
            
Word Word  
Word   |
| 119 | 41 | adantl 482 |
. . . . . . . . . . . . . . . . 17
            
Word Word         |
| 120 | | simpl 473 |
. . . . . . . . . . . . . . . . 17
            
Word Word  
            |
| 121 | 119, 120,
44 | syl2anc 693 |
. . . . . . . . . . . . . . . 16
            
Word Word               |
| 122 | 118, 121 | jca 554 |
. . . . . . . . . . . . . . 15
            
Word Word    Word              |
| 123 | 122 | ex 450 |
. . . . . . . . . . . . . 14
    
     
 
Word Word  
Word 
             |
| 124 | 123 | adantl 482 |
. . . . . . . . . . . . 13
     
             Word Word 
 Word               |
| 125 | 124 | impcom 446 |
. . . . . . . . . . . 12
   Word
Word      
           
 Word              |
| 126 | 125, 46 | syl 17 |
. . . . . . . . . . 11
   Word
Word      
           
    prefix         |
| 127 | 116, 126 | oveq12d 6668 |
. . . . . . . . . 10
   Word
Word      
           
     substr          prefix              |
| 128 | 116, 127 | oveq12d 6668 |
. . . . . . . . 9
   Word
Word      
           
     substr      ..^     substr          prefix          ..^         |
| 129 | 128 | ad2antrl 764 |
. . . . . . . 8
   ..^      Word Word  
   
             ..^    
     substr      ..^     substr          prefix          ..^         |
| 130 | 115, 129 | eleqtrrd 2704 |
. . . . . . 7
   ..^      Word Word  
   
             ..^    
     substr      ..^     substr  
       prefix         |
| 131 | | df-3an 1039 |
. . . . . . 7
   substr     Word  prefix    Word      substr      ..^     substr  
       prefix           substr     Word  prefix    Word 
     substr      ..^     substr  
       prefix          |
| 132 | 98, 130, 131 | sylanbrc 698 |
. . . . . 6
   ..^      Word Word  
   
             ..^    
  substr     Word 
prefix    Word      substr      ..^     substr  
       prefix          |
| 133 | | ccatval2 13362 |
. . . . . 6
   substr     Word  prefix    Word      substr      ..^     substr  
       prefix           substr     ++  prefix 
        prefix           substr          |
| 134 | 132, 133 | syl 17 |
. . . . 5
   ..^      Word Word  
   
             ..^    
   substr
    ++  prefix          prefix           substr          |
| 135 | 97, 134 | eqtr4d 2659 |
. . . 4
   ..^      Word Word  
   
             ..^    
   ++  substr           substr     ++  prefix          |
| 136 | 92, 135 | pm2.61ian 831 |
. . 3
    Word Word 
    
             ..^   
   ++  substr           substr     ++  prefix          |
| 137 | 20, 70, 136 | eqfnfvd 6314 |
. 2
   Word
Word      
           
  ++  substr       substr     ++  prefix       |
| 138 | 137 | ex 450 |
1
  Word
Word       
             ++  substr       substr     ++  prefix        |