Step | Hyp | Ref
| Expression |
1 | | lencl 13324 |
. . 3
 Word       |
2 | | eqeq2 2633 |
. . . . . 6
     
       |
3 | 2 | imbi1d 331 |
. . . . 5
       
         |
4 | 3 | ralbidv 2986 |
. . . 4
  
Word       
 Word           |
5 | | eqeq2 2633 |
. . . . . 6
     
       |
6 | 5 | imbi1d 331 |
. . . . 5
       
         |
7 | 6 | ralbidv 2986 |
. . . 4
  
Word       
 Word           |
8 | | eqeq2 2633 |
. . . . . 6
       
         |
9 | 8 | imbi1d 331 |
. . . . 5
         
           |
10 | 9 | ralbidv 2986 |
. . . 4
    
Word       
 Word             |
11 | | eqeq2 2633 |
. . . . . 6
    
                |
12 | 11 | imbi1d 331 |
. . . . 5
    
                    |
13 | 12 | ralbidv 2986 |
. . . 4
    
 
Word         Word               |
14 | | hasheq0 13154 |
. . . . . 6
 Word     
   |
15 | | wrdind.5 |
. . . . . . 7
 |
16 | | wrdind.1 |
. . . . . . 7

    |
17 | 15, 16 | mpbiri 248 |
. . . . . 6

  |
18 | 14, 17 | syl6bi 243 |
. . . . 5
 Word         |
19 | 18 | rgen 2922 |
. . . 4
 Word         |
20 | | fveq2 6191 |
. . . . . . . 8
           |
21 | 20 | eqeq1d 2624 |
. . . . . . 7
     
       |
22 | | wrdind.2 |
. . . . . . 7
     |
23 | 21, 22 | imbi12d 334 |
. . . . . 6
       
         |
24 | 23 | cbvralv 3171 |
. . . . 5
 
Word         Word          |
25 | | swrdcl 13419 |
. . . . . . . . . . . 12
 Word  substr          
Word   |
26 | 25 | ad2antrl 764 |
. . . . . . . . . . 11
    Word          Word
         substr           Word   |
27 | | simplr 792 |
. . . . . . . . . . 11
    Word          Word
         Word          |
28 | | simprl 794 |
. . . . . . . . . . . . 13
    Word          Word
        Word   |
29 | | fzossfz 12488 |
. . . . . . . . . . . . . 14
 ..^              |
30 | | simprr 796 |
. . . . . . . . . . . . . . . 16
    Word          Word
                |
31 | | nn0p1nn 11332 |
. . . . . . . . . . . . . . . . 17

    |
32 | 31 | ad2antrr 762 |
. . . . . . . . . . . . . . . 16
    Word          Word
            |
33 | 30, 32 | eqeltrd 2701 |
. . . . . . . . . . . . . . 15
    Word          Word
              |
34 | | fzo0end 12560 |
. . . . . . . . . . . . . . 15
    
       ..^       |
35 | 33, 34 | syl 17 |
. . . . . . . . . . . . . 14
    Word          Word
               ..^       |
36 | 29, 35 | sseldi 3601 |
. . . . . . . . . . . . 13
    Word          Word
                        |
37 | | swrd0len 13422 |
. . . . . . . . . . . . 13
  Word                    substr                    |
38 | 28, 36, 37 | syl2anc 693 |
. . . . . . . . . . . 12
    Word          Word
            substr                    |
39 | 30 | oveq1d 6665 |
. . . . . . . . . . . 12
    Word          Word
                    |
40 | | nn0cn 11302 |
. . . . . . . . . . . . . 14

  |
41 | 40 | ad2antrr 762 |
. . . . . . . . . . . . 13
    Word          Word
          |
42 | | ax-1cn 9994 |
. . . . . . . . . . . . 13
 |
43 | | pncan 10287 |
. . . . . . . . . . . . 13
 
       |
44 | 41, 42, 43 | sylancl 694 |
. . . . . . . . . . . 12
    Word          Word
              |
45 | 38, 39, 44 | 3eqtrd 2660 |
. . . . . . . . . . 11
    Word          Word
            substr              |
46 | | fveq2 6191 |
. . . . . . . . . . . . . 14
  substr                   substr              |
47 | 46 | eqeq1d 2624 |
. . . . . . . . . . . . 13
  substr               
    substr               |
48 | | vex 3203 |
. . . . . . . . . . . . . . 15
 |
49 | 48, 22 | sbcie 3470 |
. . . . . . . . . . . . . 14
   ![]. ].](_drbrack.gif)
  |
50 | | dfsbcq 3437 |
. . . . . . . . . . . . . 14
  substr            
 ![]. ].](_drbrack.gif)   substr            ![]. ].](_drbrack.gif)    |
51 | 49, 50 | syl5bbr 274 |
. . . . . . . . . . . . 13
  substr              substr            ![]. ].](_drbrack.gif)    |
52 | 47, 51 | imbi12d 334 |
. . . . . . . . . . . 12
  substr                 
     substr           
  substr            ![]. ].](_drbrack.gif)     |
53 | 52 | rspcv 3305 |
. . . . . . . . . . 11
  substr          
Word   Word             substr              substr            ![]. ].](_drbrack.gif)     |
54 | 26, 27, 45, 53 | syl3c 66 |
. . . . . . . . . 10
    Word          Word
          substr            ![]. ].](_drbrack.gif)   |
55 | 33 | nnge1d 11063 |
. . . . . . . . . . . . 13
    Word          Word
              |
56 | | wrdlenge1n0 13340 |
. . . . . . . . . . . . . 14
 Word 
       |
57 | 56 | ad2antrl 764 |
. . . . . . . . . . . . 13
    Word          Word
        
       |
58 | 55, 57 | mpbird 247 |
. . . . . . . . . . . 12
    Word          Word
          |
59 | | lswcl 13355 |
. . . . . . . . . . . 12
  Word  lastS     |
60 | 28, 58, 59 | syl2anc 693 |
. . . . . . . . . . 11
    Word          Word
        lastS
    |
61 | | oveq1 6657 |
. . . . . . . . . . . . . 14
  substr            ++        substr           ++        |
62 | 61 | sbceq1d 3440 |
. . . . . . . . . . . . 13
  substr              ++       ![]. ].](_drbrack.gif)    substr           ++       ![]. ].](_drbrack.gif)    |
63 | 50, 62 | imbi12d 334 |
. . . . . . . . . . . 12
  substr               ![]. ].](_drbrack.gif)
  ++       ![]. ].](_drbrack.gif)     substr            ![]. ].](_drbrack.gif)
   substr           ++
      ![]. ].](_drbrack.gif)     |
64 | | s1eq 13380 |
. . . . . . . . . . . . . . 15
 lastS  
      lastS       |
65 | 64 | oveq2d 6666 |
. . . . . . . . . . . . . 14
 lastS  
  substr           ++
       substr           ++   lastS        |
66 | 65 | sbceq1d 3440 |
. . . . . . . . . . . . 13
 lastS  
    substr           ++       ![]. ].](_drbrack.gif)    substr           ++   lastS       ![]. ].](_drbrack.gif)    |
67 | 66 | imbi2d 330 |
. . . . . . . . . . . 12
 lastS  
    substr            ![]. ].](_drbrack.gif)
   substr           ++
      ![]. ].](_drbrack.gif) 
  
substr          
 ![]. ].](_drbrack.gif)
   substr           ++
  lastS       ![]. ].](_drbrack.gif)     |
68 | | wrdind.6 |
. . . . . . . . . . . . 13
  Word
     |
69 | | ovex 6678 |
. . . . . . . . . . . . . 14
 ++     
 |
70 | | wrdind.3 |
. . . . . . . . . . . . . 14
  ++      
   |
71 | 69, 70 | sbcie 3470 |
. . . . . . . . . . . . 13
   ++
      ![]. ].](_drbrack.gif)   |
72 | 68, 49, 71 | 3imtr4g 285 |
. . . . . . . . . . . 12
  Word
    ![]. ].](_drbrack.gif)   ++       ![]. ].](_drbrack.gif)    |
73 | 63, 67, 72 | vtocl2ga 3274 |
. . . . . . . . . . 11
   substr           Word
lastS       substr            ![]. ].](_drbrack.gif)
   substr           ++
  lastS       ![]. ].](_drbrack.gif)    |
74 | 26, 60, 73 | syl2anc 693 |
. . . . . . . . . 10
    Word          Word
           substr          
 ![]. ].](_drbrack.gif)
   substr           ++
  lastS       ![]. ].](_drbrack.gif)    |
75 | 54, 74 | mpd 15 |
. . . . . . . . 9
    Word          Word
           substr           ++   lastS       ![]. ].](_drbrack.gif)   |
76 | | wrdfin 13323 |
. . . . . . . . . . . . . 14
 Word   |
77 | 76 | ad2antrl 764 |
. . . . . . . . . . . . 13
    Word          Word
          |
78 | | hashnncl 13157 |
. . . . . . . . . . . . 13
     
   |
79 | 77, 78 | syl 17 |
. . . . . . . . . . . 12
    Word          Word
                |
80 | 33, 79 | mpbid 222 |
. . . . . . . . . . 11
    Word          Word
          |
81 | | swrdccatwrd 13468 |
. . . . . . . . . . . 12
  Word    substr
          ++
  lastS     
  |
82 | 81 | eqcomd 2628 |
. . . . . . . . . . 11
  Word    substr           ++   lastS        |
83 | 28, 80, 82 | syl2anc 693 |
. . . . . . . . . 10
    Word          Word
          substr           ++   lastS        |
84 | | sbceq1a 3446 |
. . . . . . . . . 10
   substr           ++   lastS      
   substr           ++
  lastS       ![]. ].](_drbrack.gif)    |
85 | 83, 84 | syl 17 |
. . . . . . . . 9
    Word          Word
        
   substr           ++
  lastS       ![]. ].](_drbrack.gif)    |
86 | 75, 85 | mpbird 247 |
. . . . . . . 8
    Word          Word
          |
87 | 86 | expr 643 |
. . . . . . 7
    Word         Word            |
88 | 87 | ralrimiva 2966 |
. . . . . 6
   Word          Word            |
89 | 88 | ex 450 |
. . . . 5

 
Word         Word             |
90 | 24, 89 | syl5bi 232 |
. . . 4

 
Word         Word             |
91 | 4, 7, 10, 13, 19, 90 | nn0ind 11472 |
. . 3
    
 Word              |
92 | 1, 91 | syl 17 |
. 2
 Word  Word              |
93 | | eqidd 2623 |
. 2
 Word           |
94 | | fveq2 6191 |
. . . . 5
           |
95 | 94 | eqeq1d 2624 |
. . . 4
                     |
96 | | wrdind.4 |
. . . 4
     |
97 | 95, 96 | imbi12d 334 |
. . 3
                         |
98 | 97 | rspcv 3305 |
. 2
 Word  
Word                         |
99 | 92, 93, 98 | mp2d 49 |
1
 Word   |