| Step | Hyp | Ref | Expression | 
						
							| 1 |  | clwlkclwwlkf.c |  |-  C = { w e. ( ClWalks ` G ) | 1 <_ ( # ` ( 1st ` w ) ) } | 
						
							| 2 |  | clwlkclwwlkf.a |  |-  A = ( 1st ` U ) | 
						
							| 3 |  | clwlkclwwlkf.b |  |-  B = ( 2nd ` U ) | 
						
							| 4 |  | clwlkclwwlkf.d |  |-  D = ( 1st ` W ) | 
						
							| 5 |  | clwlkclwwlkf.e |  |-  E = ( 2nd ` W ) | 
						
							| 6 | 1 2 3 4 5 | clwlkclwwlkf1lem2 |  |-  ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) -> ( ( # ` A ) = ( # ` D ) /\ A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) ) | 
						
							| 7 |  | simprr |  |-  ( ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) /\ ( ( # ` A ) = ( # ` D ) /\ A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) ) -> A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) | 
						
							| 8 | 1 2 3 | clwlkclwwlkflem |  |-  ( U e. C -> ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) ) | 
						
							| 9 | 1 4 5 | clwlkclwwlkflem |  |-  ( W e. C -> ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) | 
						
							| 10 |  | lbfzo0 |  |-  ( 0 e. ( 0 ..^ ( # ` A ) ) <-> ( # ` A ) e. NN ) | 
						
							| 11 | 10 | biimpri |  |-  ( ( # ` A ) e. NN -> 0 e. ( 0 ..^ ( # ` A ) ) ) | 
						
							| 12 | 11 | 3ad2ant3 |  |-  ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) -> 0 e. ( 0 ..^ ( # ` A ) ) ) | 
						
							| 13 | 12 | adantr |  |-  ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) -> 0 e. ( 0 ..^ ( # ` A ) ) ) | 
						
							| 14 | 13 | adantr |  |-  ( ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) /\ ( # ` A ) = ( # ` D ) ) -> 0 e. ( 0 ..^ ( # ` A ) ) ) | 
						
							| 15 |  | fveq2 |  |-  ( i = 0 -> ( B ` i ) = ( B ` 0 ) ) | 
						
							| 16 |  | fveq2 |  |-  ( i = 0 -> ( E ` i ) = ( E ` 0 ) ) | 
						
							| 17 | 15 16 | eqeq12d |  |-  ( i = 0 -> ( ( B ` i ) = ( E ` i ) <-> ( B ` 0 ) = ( E ` 0 ) ) ) | 
						
							| 18 | 17 | rspcv |  |-  ( 0 e. ( 0 ..^ ( # ` A ) ) -> ( A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) -> ( B ` 0 ) = ( E ` 0 ) ) ) | 
						
							| 19 | 14 18 | syl |  |-  ( ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) /\ ( # ` A ) = ( # ` D ) ) -> ( A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) -> ( B ` 0 ) = ( E ` 0 ) ) ) | 
						
							| 20 |  | simpl |  |-  ( ( ( B ` ( # ` A ) ) = ( B ` 0 ) /\ ( ( B ` 0 ) = ( E ` 0 ) /\ ( E ` 0 ) = ( E ` ( # ` D ) ) ) ) -> ( B ` ( # ` A ) ) = ( B ` 0 ) ) | 
						
							| 21 |  | eqtr |  |-  ( ( ( B ` 0 ) = ( E ` 0 ) /\ ( E ` 0 ) = ( E ` ( # ` D ) ) ) -> ( B ` 0 ) = ( E ` ( # ` D ) ) ) | 
						
							| 22 | 21 | adantl |  |-  ( ( ( B ` ( # ` A ) ) = ( B ` 0 ) /\ ( ( B ` 0 ) = ( E ` 0 ) /\ ( E ` 0 ) = ( E ` ( # ` D ) ) ) ) -> ( B ` 0 ) = ( E ` ( # ` D ) ) ) | 
						
							| 23 | 20 22 | eqtrd |  |-  ( ( ( B ` ( # ` A ) ) = ( B ` 0 ) /\ ( ( B ` 0 ) = ( E ` 0 ) /\ ( E ` 0 ) = ( E ` ( # ` D ) ) ) ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) | 
						
							| 24 | 23 | exp32 |  |-  ( ( B ` ( # ` A ) ) = ( B ` 0 ) -> ( ( B ` 0 ) = ( E ` 0 ) -> ( ( E ` 0 ) = ( E ` ( # ` D ) ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) ) ) | 
						
							| 25 | 24 | com23 |  |-  ( ( B ` ( # ` A ) ) = ( B ` 0 ) -> ( ( E ` 0 ) = ( E ` ( # ` D ) ) -> ( ( B ` 0 ) = ( E ` 0 ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) ) ) | 
						
							| 26 | 25 | eqcoms |  |-  ( ( B ` 0 ) = ( B ` ( # ` A ) ) -> ( ( E ` 0 ) = ( E ` ( # ` D ) ) -> ( ( B ` 0 ) = ( E ` 0 ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) ) ) | 
						
							| 27 | 26 | 3ad2ant2 |  |-  ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) -> ( ( E ` 0 ) = ( E ` ( # ` D ) ) -> ( ( B ` 0 ) = ( E ` 0 ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) ) ) | 
						
							| 28 | 27 | com12 |  |-  ( ( E ` 0 ) = ( E ` ( # ` D ) ) -> ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) -> ( ( B ` 0 ) = ( E ` 0 ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) ) ) | 
						
							| 29 | 28 | 3ad2ant2 |  |-  ( ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) -> ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) -> ( ( B ` 0 ) = ( E ` 0 ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) ) ) | 
						
							| 30 | 29 | impcom |  |-  ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) -> ( ( B ` 0 ) = ( E ` 0 ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) ) | 
						
							| 31 | 30 | adantr |  |-  ( ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) /\ ( # ` A ) = ( # ` D ) ) -> ( ( B ` 0 ) = ( E ` 0 ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) ) | 
						
							| 32 | 31 | imp |  |-  ( ( ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) /\ ( # ` A ) = ( # ` D ) ) /\ ( B ` 0 ) = ( E ` 0 ) ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` D ) ) ) | 
						
							| 33 |  | fveq2 |  |-  ( ( # ` D ) = ( # ` A ) -> ( E ` ( # ` D ) ) = ( E ` ( # ` A ) ) ) | 
						
							| 34 | 33 | eqcoms |  |-  ( ( # ` A ) = ( # ` D ) -> ( E ` ( # ` D ) ) = ( E ` ( # ` A ) ) ) | 
						
							| 35 | 34 | adantl |  |-  ( ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) /\ ( # ` A ) = ( # ` D ) ) -> ( E ` ( # ` D ) ) = ( E ` ( # ` A ) ) ) | 
						
							| 36 | 35 | adantr |  |-  ( ( ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) /\ ( # ` A ) = ( # ` D ) ) /\ ( B ` 0 ) = ( E ` 0 ) ) -> ( E ` ( # ` D ) ) = ( E ` ( # ` A ) ) ) | 
						
							| 37 | 32 36 | eqtrd |  |-  ( ( ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) /\ ( # ` A ) = ( # ` D ) ) /\ ( B ` 0 ) = ( E ` 0 ) ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) | 
						
							| 38 | 37 | ex |  |-  ( ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) /\ ( # ` A ) = ( # ` D ) ) -> ( ( B ` 0 ) = ( E ` 0 ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) | 
						
							| 39 | 19 38 | syld |  |-  ( ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) /\ ( # ` A ) = ( # ` D ) ) -> ( A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) | 
						
							| 40 | 39 | ex |  |-  ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) -> ( ( # ` A ) = ( # ` D ) -> ( A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) ) | 
						
							| 41 | 8 9 40 | syl2an |  |-  ( ( U e. C /\ W e. C ) -> ( ( # ` A ) = ( # ` D ) -> ( A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) ) | 
						
							| 42 | 41 | impd |  |-  ( ( U e. C /\ W e. C ) -> ( ( ( # ` A ) = ( # ` D ) /\ A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) | 
						
							| 43 | 42 | 3adant3 |  |-  ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) -> ( ( ( # ` A ) = ( # ` D ) /\ A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) | 
						
							| 44 | 43 | imp |  |-  ( ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) /\ ( ( # ` A ) = ( # ` D ) /\ A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) ) -> ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) | 
						
							| 45 | 7 44 | jca |  |-  ( ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) /\ ( ( # ` A ) = ( # ` D ) /\ A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) ) -> ( A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) /\ ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) | 
						
							| 46 | 6 45 | mpdan |  |-  ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) -> ( A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) /\ ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) | 
						
							| 47 |  | fvex |  |-  ( # ` A ) e. _V | 
						
							| 48 |  | fveq2 |  |-  ( i = ( # ` A ) -> ( B ` i ) = ( B ` ( # ` A ) ) ) | 
						
							| 49 |  | fveq2 |  |-  ( i = ( # ` A ) -> ( E ` i ) = ( E ` ( # ` A ) ) ) | 
						
							| 50 | 48 49 | eqeq12d |  |-  ( i = ( # ` A ) -> ( ( B ` i ) = ( E ` i ) <-> ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) | 
						
							| 51 | 50 | ralunsn |  |-  ( ( # ` A ) e. _V -> ( A. i e. ( ( 0 ..^ ( # ` A ) ) u. { ( # ` A ) } ) ( B ` i ) = ( E ` i ) <-> ( A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) /\ ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) ) | 
						
							| 52 | 47 51 | ax-mp |  |-  ( A. i e. ( ( 0 ..^ ( # ` A ) ) u. { ( # ` A ) } ) ( B ` i ) = ( E ` i ) <-> ( A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) /\ ( B ` ( # ` A ) ) = ( E ` ( # ` A ) ) ) ) | 
						
							| 53 | 46 52 | sylibr |  |-  ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) -> A. i e. ( ( 0 ..^ ( # ` A ) ) u. { ( # ` A ) } ) ( B ` i ) = ( E ` i ) ) | 
						
							| 54 |  | nnnn0 |  |-  ( ( # ` A ) e. NN -> ( # ` A ) e. NN0 ) | 
						
							| 55 |  | elnn0uz |  |-  ( ( # ` A ) e. NN0 <-> ( # ` A ) e. ( ZZ>= ` 0 ) ) | 
						
							| 56 | 54 55 | sylib |  |-  ( ( # ` A ) e. NN -> ( # ` A ) e. ( ZZ>= ` 0 ) ) | 
						
							| 57 | 56 | 3ad2ant3 |  |-  ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) -> ( # ` A ) e. ( ZZ>= ` 0 ) ) | 
						
							| 58 | 8 57 | syl |  |-  ( U e. C -> ( # ` A ) e. ( ZZ>= ` 0 ) ) | 
						
							| 59 | 58 | 3ad2ant1 |  |-  ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) -> ( # ` A ) e. ( ZZ>= ` 0 ) ) | 
						
							| 60 |  | fzisfzounsn |  |-  ( ( # ` A ) e. ( ZZ>= ` 0 ) -> ( 0 ... ( # ` A ) ) = ( ( 0 ..^ ( # ` A ) ) u. { ( # ` A ) } ) ) | 
						
							| 61 | 59 60 | syl |  |-  ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) -> ( 0 ... ( # ` A ) ) = ( ( 0 ..^ ( # ` A ) ) u. { ( # ` A ) } ) ) | 
						
							| 62 | 53 61 | raleqtrrdv |  |-  ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) -> A. i e. ( 0 ... ( # ` A ) ) ( B ` i ) = ( E ` i ) ) |