| Step | Hyp | Ref
| Expression |
| 1 | | wwlksnredwwlkn.e |
. . . . 5
Edg   |
| 2 | 1 | wwlksnredwwlkn 26790 |
. . . 4

    WWalksN 
  WWalksN
    substr      
 lastS    lastS        |
| 3 | 2 | imp 445 |
. . 3
 
 
 WWalksN   
 WWalksN     substr      
 lastS    lastS       |
| 4 | | simpl 473 |
. . . . . . . . 9
   substr      
 lastS    lastS      substr      
  |
| 5 | 4 | adantl 482 |
. . . . . . . 8
        
   WWalksN
    WWalksN
 
  substr      
 lastS    lastS       substr      
  |
| 6 | | fveq1 6190 |
. . . . . . . . . . . . . 14
  substr             substr            |
| 7 | 6 | eqcoms 2630 |
. . . . . . . . . . . . 13
  substr      
      substr            |
| 8 | 7 | adantr 481 |
. . . . . . . . . . . 12
   substr      
      
   WWalksN
    WWalksN
         substr            |
| 9 | | eqid 2622 |
. . . . . . . . . . . . . . . . . . 19
Vtx  Vtx   |
| 10 | 9, 1 | wwlknp 26734 |
. . . . . . . . . . . . . . . . . 18
    WWalksN 
 Word Vtx            ..^                    |
| 11 | | nn0p1nn 11332 |
. . . . . . . . . . . . . . . . . . . . . . 23

    |
| 12 | | peano2nn0 11333 |
. . . . . . . . . . . . . . . . . . . . . . . 24

    |
| 13 | | nn0re 11301 |
. . . . . . . . . . . . . . . . . . . . . . . 24
  
    |
| 14 | | lep1 10862 |
. . . . . . . . . . . . . . . . . . . . . . . 24
   
       |
| 15 | 12, 13, 14 | 3syl 18 |
. . . . . . . . . . . . . . . . . . . . . . 23

        |
| 16 | | peano2nn0 11333 |
. . . . . . . . . . . . . . . . . . . . . . . . 25
  
      |
| 17 | 16 | nn0zd 11480 |
. . . . . . . . . . . . . . . . . . . . . . . 24
  
      |
| 18 | | fznn 12408 |
. . . . . . . . . . . . . . . . . . . . . . . 24
               
 
 
         |
| 19 | 12, 17, 18 | 3syl 18 |
. . . . . . . . . . . . . . . . . . . . . . 23

          
 
 
         |
| 20 | 11, 15, 19 | mpbir2and 957 |
. . . . . . . . . . . . . . . . . . . . . 22

            |
| 21 | | oveq2 6658 |
. . . . . . . . . . . . . . . . . . . . . . 23
                           |
| 22 | 21 | eleq2d 2687 |
. . . . . . . . . . . . . . . . . . . . . 22
                   
             |
| 23 | 20, 22 | syl5ibr 236 |
. . . . . . . . . . . . . . . . . . . . 21
         

            |
| 24 | 23 | adantl 482 |
. . . . . . . . . . . . . . . . . . . 20
  Word Vtx           

            |
| 25 | | simpl 473 |
. . . . . . . . . . . . . . . . . . . 20
  Word Vtx           Word Vtx    |
| 26 | 24, 25 | jctild 566 |
. . . . . . . . . . . . . . . . . . 19
  Word Vtx           

Word Vtx 
              |
| 27 | 26 | 3adant3 1081 |
. . . . . . . . . . . . . . . . . 18
  Word Vtx            ..^                    Word Vtx                |
| 28 | 10, 27 | syl 17 |
. . . . . . . . . . . . . . . . 17
    WWalksN 

 Word Vtx                |
| 29 | 28 | impcom 446 |
. . . . . . . . . . . . . . . 16
 
 
 WWalksN    Word Vtx  
            |
| 30 | 29 | adantl 482 |
. . . . . . . . . . . . . . 15
      
   WWalksN     Word Vtx               |
| 31 | 30 | adantr 481 |
. . . . . . . . . . . . . 14
       
   WWalksN
    WWalksN
 
 Word Vtx               |
| 32 | 31 | adantl 482 |
. . . . . . . . . . . . 13
   substr      
      
   WWalksN
    WWalksN
   
Word Vtx 
             |
| 33 | | swrd0fv0 13440 |
. . . . . . . . . . . . 13
  Word Vtx  
            substr                |
| 34 | 32, 33 | syl 17 |
. . . . . . . . . . . 12
   substr      
      
   WWalksN
    WWalksN
     substr
               |
| 35 | | simprll 802 |
. . . . . . . . . . . 12
   substr      
      
   WWalksN
    WWalksN
         |
| 36 | 8, 34, 35 | 3eqtrd 2660 |
. . . . . . . . . . 11
   substr      
      
   WWalksN
    WWalksN
         |
| 37 | 36 | ex 450 |
. . . . . . . . . 10
  substr      
       
   WWalksN
    WWalksN
 
       |
| 38 | 37 | adantr 481 |
. . . . . . . . 9
   substr      
 lastS    lastS            
   WWalksN
    WWalksN
 
       |
| 39 | 38 | impcom 446 |
. . . . . . . 8
        
   WWalksN
    WWalksN
 
  substr      
 lastS    lastS            |
| 40 | | simpr 477 |
. . . . . . . . 9
   substr      
 lastS    lastS      lastS    lastS      |
| 41 | 40 | adantl 482 |
. . . . . . . 8
        
   WWalksN
    WWalksN
 
  substr      
 lastS    lastS       lastS    lastS      |
| 42 | 5, 39, 41 | 3jca 1242 |
. . . . . . 7
        
   WWalksN
    WWalksN
 
  substr      
 lastS    lastS        substr
           lastS    lastS       |
| 43 | 42 | ex 450 |
. . . . . 6
       
   WWalksN
    WWalksN
 
   substr
       lastS    lastS    
  substr      
     lastS   
lastS        |
| 44 | 43 | reximdva 3017 |
. . . . 5
      
   WWalksN       WWalksN
    substr      
 lastS    lastS       WWalksN
    substr      
   
 lastS    lastS        |
| 45 | 44 | ex 450 |
. . . 4
          WWalksN      WWalksN
    substr      
 lastS    lastS       WWalksN
    substr      
   
 lastS    lastS         |
| 46 | 45 | com13 88 |
. . 3
   WWalksN     substr      
 lastS    lastS    
 
   WWalksN
 
    
  WWalksN
    substr      
   
 lastS    lastS         |
| 47 | 3, 46 | mpcom 38 |
. 2
 
 
 WWalksN          WWalksN     substr      
     lastS   
lastS        |
| 48 | 29, 33 | syl 17 |
. . . . . . . . 9
 
 
 WWalksN     substr                |
| 49 | 48 | eqcomd 2628 |
. . . . . . . 8
 
 
 WWalksN         substr            |
| 50 | 49 | adantl 482 |
. . . . . . 7
    substr      
     
   WWalksN
         substr            |
| 51 | | fveq1 6190 |
. . . . . . . . 9
  substr      
  substr                |
| 52 | 51 | adantr 481 |
. . . . . . . 8
   substr      
       substr
               |
| 53 | 52 | adantr 481 |
. . . . . . 7
    substr      
     
   WWalksN
     substr
               |
| 54 | | simpr 477 |
. . . . . . . 8
   substr      
           |
| 55 | 54 | adantr 481 |
. . . . . . 7
    substr      
     
   WWalksN
         |
| 56 | 50, 53, 55 | 3eqtrd 2660 |
. . . . . 6
    substr      
     
   WWalksN
         |
| 57 | 56 | ex 450 |
. . . . 5
   substr      
          WWalksN          |
| 58 | 57 | 3adant3 1081 |
. . . 4
   substr      
   
 lastS    lastS          WWalksN          |
| 59 | 58 | com12 32 |
. . 3
 
 
 WWalksN      substr            lastS   
lastS            |
| 60 | 59 | rexlimdvw 3034 |
. 2
 
 
 WWalksN      WWalksN
    substr      
   
 lastS    lastS            |
| 61 | 47, 60 | impbid 202 |
1
 
 
 WWalksN        
 WWalksN     substr      
     lastS   
lastS        |