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Theorem wwlksnredwwlkn 26790
Description: For each walk (as word) of length at least 1 there is a shorter walk (as word). (Contributed by Alexander van der Vekens, 22-Aug-2018.) (Revised by AV, 18-Apr-2021.)
Hypothesis
Ref Expression
wwlksnredwwlkn.e  |-  E  =  (Edg `  G )
Assertion
Ref Expression
wwlksnredwwlkn  |-  ( N  e.  NN0  ->  ( W  e.  ( ( N  +  1 ) WWalksN  G
)  ->  E. y  e.  ( N WWalksN  G )
( ( W substr  <. 0 ,  ( N  + 
1 ) >. )  =  y  /\  { ( lastS  `  y ) ,  ( lastS  `  W ) }  e.  E ) ) )
Distinct variable groups:    y, E    y, G    y, N    y, W

Proof of Theorem wwlksnredwwlkn
Dummy variable  i is distinct from all other variables.
StepHypRef Expression
1 eqidd 2623 . . 3  |-  ( ( N  e.  NN0  /\  W  e.  ( ( N  +  1 ) WWalksN  G ) )  -> 
( W substr  <. 0 ,  ( N  +  1 ) >. )  =  ( W substr  <. 0 ,  ( N  +  1 )
>. ) )
2 eqid 2622 . . . . 5  |-  (Vtx `  G )  =  (Vtx
`  G )
3 wwlksnredwwlkn.e . . . . 5  |-  E  =  (Edg `  G )
42, 3wwlknp 26734 . . . 4  |-  ( W  e.  ( ( N  +  1 ) WWalksN  G
)  ->  ( W  e. Word  (Vtx `  G )  /\  ( # `  W
)  =  ( ( N  +  1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )
5 simprl 794 . . . . . . . . 9  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 ) ) )  ->  W  e. Word  (Vtx `  G
) )
6 peano2nn0 11333 . . . . . . . . . . . . 13  |-  ( N  e.  NN0  ->  ( N  +  1 )  e. 
NN0 )
7 peano2nn0 11333 . . . . . . . . . . . . 13  |-  ( ( N  +  1 )  e.  NN0  ->  ( ( N  +  1 )  +  1 )  e. 
NN0 )
86, 7syl 17 . . . . . . . . . . . 12  |-  ( N  e.  NN0  ->  ( ( N  +  1 )  +  1 )  e. 
NN0 )
9 id 22 . . . . . . . . . . . . 13  |-  ( N  e.  NN0  ->  N  e. 
NN0 )
10 nn0p1nn 11332 . . . . . . . . . . . . . 14  |-  ( ( N  +  1 )  e.  NN0  ->  ( ( N  +  1 )  +  1 )  e.  NN )
116, 10syl 17 . . . . . . . . . . . . 13  |-  ( N  e.  NN0  ->  ( ( N  +  1 )  +  1 )  e.  NN )
12 nn0re 11301 . . . . . . . . . . . . . . 15  |-  ( N  e.  NN0  ->  N  e.  RR )
13 id 22 . . . . . . . . . . . . . . . 16  |-  ( N  e.  RR  ->  N  e.  RR )
14 peano2re 10209 . . . . . . . . . . . . . . . 16  |-  ( N  e.  RR  ->  ( N  +  1 )  e.  RR )
15 peano2re 10209 . . . . . . . . . . . . . . . . 17  |-  ( ( N  +  1 )  e.  RR  ->  (
( N  +  1 )  +  1 )  e.  RR )
1614, 15syl 17 . . . . . . . . . . . . . . . 16  |-  ( N  e.  RR  ->  (
( N  +  1 )  +  1 )  e.  RR )
1713, 14, 163jca 1242 . . . . . . . . . . . . . . 15  |-  ( N  e.  RR  ->  ( N  e.  RR  /\  ( N  +  1 )  e.  RR  /\  (
( N  +  1 )  +  1 )  e.  RR ) )
1812, 17syl 17 . . . . . . . . . . . . . 14  |-  ( N  e.  NN0  ->  ( N  e.  RR  /\  ( N  +  1 )  e.  RR  /\  (
( N  +  1 )  +  1 )  e.  RR ) )
1912ltp1d 10954 . . . . . . . . . . . . . 14  |-  ( N  e.  NN0  ->  N  < 
( N  +  1 ) )
20 nn0re 11301 . . . . . . . . . . . . . . . 16  |-  ( ( N  +  1 )  e.  NN0  ->  ( N  +  1 )  e.  RR )
216, 20syl 17 . . . . . . . . . . . . . . 15  |-  ( N  e.  NN0  ->  ( N  +  1 )  e.  RR )
2221ltp1d 10954 . . . . . . . . . . . . . 14  |-  ( N  e.  NN0  ->  ( N  +  1 )  < 
( ( N  + 
1 )  +  1 ) )
23 lttr 10114 . . . . . . . . . . . . . . 15  |-  ( ( N  e.  RR  /\  ( N  +  1
)  e.  RR  /\  ( ( N  + 
1 )  +  1 )  e.  RR )  ->  ( ( N  <  ( N  + 
1 )  /\  ( N  +  1 )  <  ( ( N  +  1 )  +  1 ) )  ->  N  <  ( ( N  +  1 )  +  1 ) ) )
2423imp 445 . . . . . . . . . . . . . 14  |-  ( ( ( N  e.  RR  /\  ( N  +  1 )  e.  RR  /\  ( ( N  + 
1 )  +  1 )  e.  RR )  /\  ( N  < 
( N  +  1 )  /\  ( N  +  1 )  < 
( ( N  + 
1 )  +  1 ) ) )  ->  N  <  ( ( N  +  1 )  +  1 ) )
2518, 19, 22, 24syl12anc 1324 . . . . . . . . . . . . 13  |-  ( N  e.  NN0  ->  N  < 
( ( N  + 
1 )  +  1 ) )
26 elfzo0 12508 . . . . . . . . . . . . 13  |-  ( N  e.  ( 0..^ ( ( N  +  1 )  +  1 ) )  <->  ( N  e. 
NN0  /\  ( ( N  +  1 )  +  1 )  e.  NN  /\  N  < 
( ( N  + 
1 )  +  1 ) ) )
279, 11, 25, 26syl3anbrc 1246 . . . . . . . . . . . 12  |-  ( N  e.  NN0  ->  N  e.  ( 0..^ ( ( N  +  1 )  +  1 ) ) )
28 fz0add1fz1 12537 . . . . . . . . . . . 12  |-  ( ( ( ( N  + 
1 )  +  1 )  e.  NN0  /\  N  e.  ( 0..^ ( ( N  + 
1 )  +  1 ) ) )  -> 
( N  +  1 )  e.  ( 1 ... ( ( N  +  1 )  +  1 ) ) )
298, 27, 28syl2anc 693 . . . . . . . . . . 11  |-  ( N  e.  NN0  ->  ( N  +  1 )  e.  ( 1 ... (
( N  +  1 )  +  1 ) ) )
3029adantr 481 . . . . . . . . . 10  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 ) ) )  -> 
( N  +  1 )  e.  ( 1 ... ( ( N  +  1 )  +  1 ) ) )
31 oveq2 6658 . . . . . . . . . . . . 13  |-  ( (
# `  W )  =  ( ( N  +  1 )  +  1 )  ->  (
1 ... ( # `  W
) )  =  ( 1 ... ( ( N  +  1 )  +  1 ) ) )
3231eleq2d 2687 . . . . . . . . . . . 12  |-  ( (
# `  W )  =  ( ( N  +  1 )  +  1 )  ->  (
( N  +  1 )  e.  ( 1 ... ( # `  W
) )  <->  ( N  +  1 )  e.  ( 1 ... (
( N  +  1 )  +  1 ) ) ) )
3332adantl 482 . . . . . . . . . . 11  |-  ( ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 ) )  ->  (
( N  +  1 )  e.  ( 1 ... ( # `  W
) )  <->  ( N  +  1 )  e.  ( 1 ... (
( N  +  1 )  +  1 ) ) ) )
3433adantl 482 . . . . . . . . . 10  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 ) ) )  -> 
( ( N  + 
1 )  e.  ( 1 ... ( # `  W ) )  <->  ( N  +  1 )  e.  ( 1 ... (
( N  +  1 )  +  1 ) ) ) )
3530, 34mpbird 247 . . . . . . . . 9  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 ) ) )  -> 
( N  +  1 )  e.  ( 1 ... ( # `  W
) ) )
365, 35jca 554 . . . . . . . 8  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 ) ) )  -> 
( W  e. Word  (Vtx `  G )  /\  ( N  +  1 )  e.  ( 1 ... ( # `  W
) ) ) )
37363adantr3 1222 . . . . . . 7  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  ( W  e. Word  (Vtx `  G )  /\  ( N  +  1 )  e.  ( 1 ... ( # `  W
) ) ) )
38 swrd0fvlsw 13443 . . . . . . 7  |-  ( ( W  e. Word  (Vtx `  G )  /\  ( N  +  1 )  e.  ( 1 ... ( # `  W
) ) )  -> 
( lastS  `  ( W substr  <. 0 ,  ( N  + 
1 ) >. )
)  =  ( W `
 ( ( N  +  1 )  - 
1 ) ) )
3937, 38syl 17 . . . . . 6  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  ( lastS  `  ( W substr  <. 0 ,  ( N  +  1 )
>. ) )  =  ( W `  ( ( N  +  1 )  -  1 ) ) )
40 lsw 13351 . . . . . . . 8  |-  ( W  e. Word  (Vtx `  G
)  ->  ( lastS  `  W
)  =  ( W `
 ( ( # `  W )  -  1 ) ) )
41403ad2ant1 1082 . . . . . . 7  |-  ( ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E )  ->  ( lastS  `  W )  =  ( W `  ( ( # `  W
)  -  1 ) ) )
4241adantl 482 . . . . . 6  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  ( lastS  `  W
)  =  ( W `
 ( ( # `  W )  -  1 ) ) )
4339, 42preq12d 4276 . . . . 5  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  { ( lastS  `  ( W substr  <. 0 ,  ( N  + 
1 ) >. )
) ,  ( lastS  `  W
) }  =  {
( W `  (
( N  +  1 )  -  1 ) ) ,  ( W `
 ( ( # `  W )  -  1 ) ) } )
44 oveq1 6657 . . . . . . . . . . 11  |-  ( (
# `  W )  =  ( ( N  +  1 )  +  1 )  ->  (
( # `  W )  -  1 )  =  ( ( ( N  +  1 )  +  1 )  -  1 ) )
45443ad2ant2 1083 . . . . . . . . . 10  |-  ( ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E )  ->  ( ( # `  W )  -  1 )  =  ( ( ( N  +  1 )  +  1 )  -  1 ) )
4645adantl 482 . . . . . . . . 9  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  ( ( # `
 W )  - 
1 )  =  ( ( ( N  + 
1 )  +  1 )  -  1 ) )
4746fveq2d 6195 . . . . . . . 8  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  ( W `  ( ( # `  W
)  -  1 ) )  =  ( W `
 ( ( ( N  +  1 )  +  1 )  - 
1 ) ) )
4847preq2d 4275 . . . . . . 7  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  { ( W `  ( ( N  +  1 )  -  1 ) ) ,  ( W `  ( ( # `  W
)  -  1 ) ) }  =  {
( W `  (
( N  +  1 )  -  1 ) ) ,  ( W `
 ( ( ( N  +  1 )  +  1 )  - 
1 ) ) } )
49 nn0cn 11302 . . . . . . . . . . 11  |-  ( N  e.  NN0  ->  N  e.  CC )
50 1cnd 10056 . . . . . . . . . . 11  |-  ( N  e.  NN0  ->  1  e.  CC )
5149, 50pncand 10393 . . . . . . . . . 10  |-  ( N  e.  NN0  ->  ( ( N  +  1 )  -  1 )  =  N )
5251fveq2d 6195 . . . . . . . . 9  |-  ( N  e.  NN0  ->  ( W `
 ( ( N  +  1 )  - 
1 ) )  =  ( W `  N
) )
536nn0cnd 11353 . . . . . . . . . . 11  |-  ( N  e.  NN0  ->  ( N  +  1 )  e.  CC )
5453, 50pncand 10393 . . . . . . . . . 10  |-  ( N  e.  NN0  ->  ( ( ( N  +  1 )  +  1 )  -  1 )  =  ( N  +  1 ) )
5554fveq2d 6195 . . . . . . . . 9  |-  ( N  e.  NN0  ->  ( W `
 ( ( ( N  +  1 )  +  1 )  - 
1 ) )  =  ( W `  ( N  +  1 ) ) )
5652, 55preq12d 4276 . . . . . . . 8  |-  ( N  e.  NN0  ->  { ( W `  ( ( N  +  1 )  -  1 ) ) ,  ( W `  ( ( ( N  +  1 )  +  1 )  -  1 ) ) }  =  { ( W `  N ) ,  ( W `  ( N  +  1 ) ) } )
5756adantr 481 . . . . . . 7  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  { ( W `  ( ( N  +  1 )  -  1 ) ) ,  ( W `  ( ( ( N  +  1 )  +  1 )  -  1 ) ) }  =  { ( W `  N ) ,  ( W `  ( N  +  1 ) ) } )
5848, 57eqtrd 2656 . . . . . 6  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  { ( W `  ( ( N  +  1 )  -  1 ) ) ,  ( W `  ( ( # `  W
)  -  1 ) ) }  =  {
( W `  N
) ,  ( W `
 ( N  + 
1 ) ) } )
59 fveq2 6191 . . . . . . . . . . . 12  |-  ( i  =  N  ->  ( W `  i )  =  ( W `  N ) )
60 oveq1 6657 . . . . . . . . . . . . 13  |-  ( i  =  N  ->  (
i  +  1 )  =  ( N  + 
1 ) )
6160fveq2d 6195 . . . . . . . . . . . 12  |-  ( i  =  N  ->  ( W `  ( i  +  1 ) )  =  ( W `  ( N  +  1
) ) )
6259, 61preq12d 4276 . . . . . . . . . . 11  |-  ( i  =  N  ->  { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  =  { ( W `  N ) ,  ( W `  ( N  +  1 ) ) } )
6362eleq1d 2686 . . . . . . . . . 10  |-  ( i  =  N  ->  ( { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E  <->  { ( W `  N ) ,  ( W `  ( N  +  1
) ) }  e.  E ) )
6463rspcv 3305 . . . . . . . . 9  |-  ( N  e.  ( 0..^ ( N  +  1 ) )  ->  ( A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E  ->  { ( W `
 N ) ,  ( W `  ( N  +  1 ) ) }  e.  E
) )
65 fzonn0p1 12544 . . . . . . . . 9  |-  ( N  e.  NN0  ->  N  e.  ( 0..^ ( N  +  1 ) ) )
6664, 65syl11 33 . . . . . . . 8  |-  ( A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E  ->  ( N  e. 
NN0  ->  { ( W `
 N ) ,  ( W `  ( N  +  1 ) ) }  e.  E
) )
67663ad2ant3 1084 . . . . . . 7  |-  ( ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E )  ->  ( N  e. 
NN0  ->  { ( W `
 N ) ,  ( W `  ( N  +  1 ) ) }  e.  E
) )
6867impcom 446 . . . . . 6  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  { ( W `  N ) ,  ( W `  ( N  +  1
) ) }  e.  E )
6958, 68eqeltrd 2701 . . . . 5  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  { ( W `  ( ( N  +  1 )  -  1 ) ) ,  ( W `  ( ( # `  W
)  -  1 ) ) }  e.  E
)
7043, 69eqeltrd 2701 . . . 4  |-  ( ( N  e.  NN0  /\  ( W  e. Word  (Vtx `  G )  /\  ( # `
 W )  =  ( ( N  + 
1 )  +  1 )  /\  A. i  e.  ( 0..^ ( N  +  1 ) ) { ( W `  i ) ,  ( W `  ( i  +  1 ) ) }  e.  E ) )  ->  { ( lastS  `  ( W substr  <. 0 ,  ( N  + 
1 ) >. )
) ,  ( lastS  `  W
) }  e.  E
)
714, 70sylan2 491 . . 3  |-  ( ( N  e.  NN0  /\  W  e.  ( ( N  +  1 ) WWalksN  G ) )  ->  { ( lastS  `  ( W substr  <. 0 ,  ( N  +  1 ) >.
) ) ,  ( lastS  `  W ) }  e.  E )
72 wwlksnred 26787 . . . . 5  |-  ( N  e.  NN0  ->  ( W  e.  ( ( N  +  1 ) WWalksN  G
)  ->  ( W substr  <.
0 ,  ( N  +  1 ) >.
)  e.  ( N WWalksN  G ) ) )
7372imp 445 . . . 4  |-  ( ( N  e.  NN0  /\  W  e.  ( ( N  +  1 ) WWalksN  G ) )  -> 
( W substr  <. 0 ,  ( N  +  1 ) >. )  e.  ( N WWalksN  G ) )
74 eqeq2 2633 . . . . . 6  |-  ( y  =  ( W substr  <. 0 ,  ( N  + 
1 ) >. )  ->  ( ( W substr  <. 0 ,  ( N  + 
1 ) >. )  =  y  <->  ( W substr  <. 0 ,  ( N  + 
1 ) >. )  =  ( W substr  <. 0 ,  ( N  + 
1 ) >. )
) )
75 fveq2 6191 . . . . . . . 8  |-  ( y  =  ( W substr  <. 0 ,  ( N  + 
1 ) >. )  ->  ( lastS  `  y )  =  ( lastS  `  ( W substr  <. 0 ,  ( N  +  1 ) >.
) ) )
7675preq1d 4274 . . . . . . 7  |-  ( y  =  ( W substr  <. 0 ,  ( N  + 
1 ) >. )  ->  { ( lastS  `  y
) ,  ( lastS  `  W
) }  =  {
( lastS  `  ( W substr  <. 0 ,  ( N  + 
1 ) >. )
) ,  ( lastS  `  W
) } )
7776eleq1d 2686 . . . . . 6  |-  ( y  =  ( W substr  <. 0 ,  ( N  + 
1 ) >. )  ->  ( { ( lastS  `  y
) ,  ( lastS  `  W
) }  e.  E  <->  { ( lastS  `  ( W substr  <.
0 ,  ( N  +  1 ) >.
) ) ,  ( lastS  `  W ) }  e.  E ) )
7874, 77anbi12d 747 . . . . 5  |-  ( y  =  ( W substr  <. 0 ,  ( N  + 
1 ) >. )  ->  ( ( ( W substr  <. 0 ,  ( N  +  1 ) >.
)  =  y  /\  { ( lastS  `  y ) ,  ( lastS  `  W ) }  e.  E )  <-> 
( ( W substr  <. 0 ,  ( N  + 
1 ) >. )  =  ( W substr  <. 0 ,  ( N  + 
1 ) >. )  /\  { ( lastS  `  ( W substr  <. 0 ,  ( N  +  1 )
>. ) ) ,  ( lastS  `  W ) }  e.  E ) ) )
7978adantl 482 . . . 4  |-  ( ( ( N  e.  NN0  /\  W  e.  ( ( N  +  1 ) WWalksN  G ) )  /\  y  =  ( W substr  <.
0 ,  ( N  +  1 ) >.
) )  ->  (
( ( W substr  <. 0 ,  ( N  + 
1 ) >. )  =  y  /\  { ( lastS  `  y ) ,  ( lastS  `  W ) }  e.  E )  <->  ( ( W substr  <. 0 ,  ( N  +  1 )
>. )  =  ( W substr  <. 0 ,  ( N  +  1 )
>. )  /\  { ( lastS  `  ( W substr  <. 0 ,  ( N  + 
1 ) >. )
) ,  ( lastS  `  W
) }  e.  E
) ) )
8073, 79rspcedv 3313 . . 3  |-  ( ( N  e.  NN0  /\  W  e.  ( ( N  +  1 ) WWalksN  G ) )  -> 
( ( ( W substr  <. 0 ,  ( N  +  1 ) >.
)  =  ( W substr  <. 0 ,  ( N  +  1 ) >.
)  /\  { ( lastS  `  ( W substr  <. 0 ,  ( N  + 
1 ) >. )
) ,  ( lastS  `  W
) }  e.  E
)  ->  E. y  e.  ( N WWalksN  G )
( ( W substr  <. 0 ,  ( N  + 
1 ) >. )  =  y  /\  { ( lastS  `  y ) ,  ( lastS  `  W ) }  e.  E ) ) )
811, 71, 80mp2and 715 . 2  |-  ( ( N  e.  NN0  /\  W  e.  ( ( N  +  1 ) WWalksN  G ) )  ->  E. y  e.  ( N WWalksN  G ) ( ( W substr  <. 0 ,  ( N  +  1 )
>. )  =  y  /\  { ( lastS  `  y
) ,  ( lastS  `  W
) }  e.  E
) )
8281ex 450 1  |-  ( N  e.  NN0  ->  ( W  e.  ( ( N  +  1 ) WWalksN  G
)  ->  E. y  e.  ( N WWalksN  G )
( ( W substr  <. 0 ,  ( N  + 
1 ) >. )  =  y  /\  { ( lastS  `  y ) ,  ( lastS  `  W ) }  e.  E ) ) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    <-> wb 196    /\ wa 384    /\ w3a 1037    = wceq 1483    e. wcel 1990   A.wral 2912   E.wrex 2913   {cpr 4179   <.cop 4183   class class class wbr 4653   ` cfv 5888  (class class class)co 6650   RRcr 9935   0cc0 9936   1c1 9937    + caddc 9939    < clt 10074    - cmin 10266   NNcn 11020   NN0cn0 11292   ...cfz 12326  ..^cfzo 12465   #chash 13117  Word cword 13291   lastS clsw 13292   substr csubstr 13295  Vtxcvtx 25874  Edgcedg 25939   WWalksN cwwlksn 26718
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-rep 4771  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949  ax-cnex 9992  ax-resscn 9993  ax-1cn 9994  ax-icn 9995  ax-addcl 9996  ax-addrcl 9997  ax-mulcl 9998  ax-mulrcl 9999  ax-mulcom 10000  ax-addass 10001  ax-mulass 10002  ax-distr 10003  ax-i2m1 10004  ax-1ne0 10005  ax-1rid 10006  ax-rnegex 10007  ax-rrecex 10008  ax-cnre 10009  ax-pre-lttri 10010  ax-pre-lttrn 10011  ax-pre-ltadd 10012  ax-pre-mulgt0 10013
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1038  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-nel 2898  df-ral 2917  df-rex 2918  df-reu 2919  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-pss 3590  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-tp 4182  df-op 4184  df-uni 4437  df-int 4476  df-iun 4522  df-br 4654  df-opab 4713  df-mpt 4730  df-tr 4753  df-id 5024  df-eprel 5029  df-po 5035  df-so 5036  df-fr 5073  df-we 5075  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-pred 5680  df-ord 5726  df-on 5727  df-lim 5728  df-suc 5729  df-iota 5851  df-fun 5890  df-fn 5891  df-f 5892  df-f1 5893  df-fo 5894  df-f1o 5895  df-fv 5896  df-riota 6611  df-ov 6653  df-oprab 6654  df-mpt2 6655  df-om 7066  df-1st 7168  df-2nd 7169  df-wrecs 7407  df-recs 7468  df-rdg 7506  df-1o 7560  df-oadd 7564  df-er 7742  df-map 7859  df-pm 7860  df-en 7956  df-dom 7957  df-sdom 7958  df-fin 7959  df-card 8765  df-pnf 10076  df-mnf 10077  df-xr 10078  df-ltxr 10079  df-le 10080  df-sub 10268  df-neg 10269  df-nn 11021  df-n0 11293  df-z 11378  df-uz 11688  df-fz 12327  df-fzo 12466  df-hash 13118  df-word 13299  df-lsw 13300  df-substr 13303  df-wwlks 26722  df-wwlksn 26723
This theorem is referenced by:  wwlksnredwwlkn0  26791
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