| 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 | clwlkclwwlkflem |  |-  ( U e. C -> ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) ) | 
						
							| 7 | 1 4 5 | clwlkclwwlkflem |  |-  ( W e. C -> ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) | 
						
							| 8 | 6 7 | anim12i |  |-  ( ( U e. C /\ W e. C ) -> ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) ) | 
						
							| 9 |  | eqid |  |-  ( Vtx ` G ) = ( Vtx ` G ) | 
						
							| 10 | 9 | wlkpwrd |  |-  ( A ( Walks ` G ) B -> B e. Word ( Vtx ` G ) ) | 
						
							| 11 | 10 | 3ad2ant1 |  |-  ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) -> B e. Word ( Vtx ` G ) ) | 
						
							| 12 | 9 | wlkpwrd |  |-  ( D ( Walks ` G ) E -> E e. Word ( Vtx ` G ) ) | 
						
							| 13 | 12 | 3ad2ant1 |  |-  ( ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) -> E e. Word ( Vtx ` G ) ) | 
						
							| 14 | 11 13 | anim12i |  |-  ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) -> ( B e. Word ( Vtx ` G ) /\ E e. Word ( Vtx ` G ) ) ) | 
						
							| 15 |  | nnnn0 |  |-  ( ( # ` A ) e. NN -> ( # ` A ) e. NN0 ) | 
						
							| 16 | 15 | 3ad2ant3 |  |-  ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) -> ( # ` A ) e. NN0 ) | 
						
							| 17 |  | nnnn0 |  |-  ( ( # ` D ) e. NN -> ( # ` D ) e. NN0 ) | 
						
							| 18 | 17 | 3ad2ant3 |  |-  ( ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) -> ( # ` D ) e. NN0 ) | 
						
							| 19 | 16 18 | anim12i |  |-  ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) -> ( ( # ` A ) e. NN0 /\ ( # ` D ) e. NN0 ) ) | 
						
							| 20 |  | wlklenvp1 |  |-  ( A ( Walks ` G ) B -> ( # ` B ) = ( ( # ` A ) + 1 ) ) | 
						
							| 21 |  | nnre |  |-  ( ( # ` A ) e. NN -> ( # ` A ) e. RR ) | 
						
							| 22 | 21 | lep1d |  |-  ( ( # ` A ) e. NN -> ( # ` A ) <_ ( ( # ` A ) + 1 ) ) | 
						
							| 23 |  | breq2 |  |-  ( ( # ` B ) = ( ( # ` A ) + 1 ) -> ( ( # ` A ) <_ ( # ` B ) <-> ( # ` A ) <_ ( ( # ` A ) + 1 ) ) ) | 
						
							| 24 | 22 23 | imbitrrid |  |-  ( ( # ` B ) = ( ( # ` A ) + 1 ) -> ( ( # ` A ) e. NN -> ( # ` A ) <_ ( # ` B ) ) ) | 
						
							| 25 | 20 24 | syl |  |-  ( A ( Walks ` G ) B -> ( ( # ` A ) e. NN -> ( # ` A ) <_ ( # ` B ) ) ) | 
						
							| 26 | 25 | a1d |  |-  ( A ( Walks ` G ) B -> ( ( B ` 0 ) = ( B ` ( # ` A ) ) -> ( ( # ` A ) e. NN -> ( # ` A ) <_ ( # ` B ) ) ) ) | 
						
							| 27 | 26 | 3imp |  |-  ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) -> ( # ` A ) <_ ( # ` B ) ) | 
						
							| 28 |  | wlklenvp1 |  |-  ( D ( Walks ` G ) E -> ( # ` E ) = ( ( # ` D ) + 1 ) ) | 
						
							| 29 |  | nnre |  |-  ( ( # ` D ) e. NN -> ( # ` D ) e. RR ) | 
						
							| 30 | 29 | lep1d |  |-  ( ( # ` D ) e. NN -> ( # ` D ) <_ ( ( # ` D ) + 1 ) ) | 
						
							| 31 |  | breq2 |  |-  ( ( # ` E ) = ( ( # ` D ) + 1 ) -> ( ( # ` D ) <_ ( # ` E ) <-> ( # ` D ) <_ ( ( # ` D ) + 1 ) ) ) | 
						
							| 32 | 30 31 | imbitrrid |  |-  ( ( # ` E ) = ( ( # ` D ) + 1 ) -> ( ( # ` D ) e. NN -> ( # ` D ) <_ ( # ` E ) ) ) | 
						
							| 33 | 28 32 | syl |  |-  ( D ( Walks ` G ) E -> ( ( # ` D ) e. NN -> ( # ` D ) <_ ( # ` E ) ) ) | 
						
							| 34 | 33 | a1d |  |-  ( D ( Walks ` G ) E -> ( ( E ` 0 ) = ( E ` ( # ` D ) ) -> ( ( # ` D ) e. NN -> ( # ` D ) <_ ( # ` E ) ) ) ) | 
						
							| 35 | 34 | 3imp |  |-  ( ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) -> ( # ` D ) <_ ( # ` E ) ) | 
						
							| 36 | 27 35 | anim12i |  |-  ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) -> ( ( # ` A ) <_ ( # ` B ) /\ ( # ` D ) <_ ( # ` E ) ) ) | 
						
							| 37 | 14 19 36 | 3jca |  |-  ( ( ( A ( Walks ` G ) B /\ ( B ` 0 ) = ( B ` ( # ` A ) ) /\ ( # ` A ) e. NN ) /\ ( D ( Walks ` G ) E /\ ( E ` 0 ) = ( E ` ( # ` D ) ) /\ ( # ` D ) e. NN ) ) -> ( ( B e. Word ( Vtx ` G ) /\ E e. Word ( Vtx ` G ) ) /\ ( ( # ` A ) e. NN0 /\ ( # ` D ) e. NN0 ) /\ ( ( # ` A ) <_ ( # ` B ) /\ ( # ` D ) <_ ( # ` E ) ) ) ) | 
						
							| 38 |  | pfxeq |  |-  ( ( ( B e. Word ( Vtx ` G ) /\ E e. Word ( Vtx ` G ) ) /\ ( ( # ` A ) e. NN0 /\ ( # ` D ) e. NN0 ) /\ ( ( # ` A ) <_ ( # ` B ) /\ ( # ` D ) <_ ( # ` E ) ) ) -> ( ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) <-> ( ( # ` A ) = ( # ` D ) /\ A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) ) ) | 
						
							| 39 | 8 37 38 | 3syl |  |-  ( ( U e. C /\ W e. C ) -> ( ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) <-> ( ( # ` A ) = ( # ` D ) /\ A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) ) ) | 
						
							| 40 | 39 | biimp3a |  |-  ( ( U e. C /\ W e. C /\ ( B prefix ( # ` A ) ) = ( E prefix ( # ` D ) ) ) -> ( ( # ` A ) = ( # ` D ) /\ A. i e. ( 0 ..^ ( # ` A ) ) ( B ` i ) = ( E ` i ) ) ) |