| Step | Hyp | Ref | Expression | 
						
							| 1 |  | clwlkclwwlkf.c |  |-  C = { w e. ( ClWalks ` G ) | 1 <_ ( # ` ( 1st ` w ) ) } | 
						
							| 2 |  | clwlkclwwlkf.f |  |-  F = ( c e. C |-> ( ( 2nd ` c ) prefix ( ( # ` ( 2nd ` c ) ) - 1 ) ) ) | 
						
							| 3 | 1 2 | clwlkclwwlkf |  |-  ( G e. USPGraph -> F : C --> ( ClWWalks ` G ) ) | 
						
							| 4 |  | clwwlkgt0 |  |-  ( w e. ( ClWWalks ` G ) -> 0 < ( # ` w ) ) | 
						
							| 5 |  | eqid |  |-  ( Vtx ` G ) = ( Vtx ` G ) | 
						
							| 6 | 5 | clwwlkbp |  |-  ( w e. ( ClWWalks ` G ) -> ( G e. _V /\ w e. Word ( Vtx ` G ) /\ w =/= (/) ) ) | 
						
							| 7 |  | lencl |  |-  ( w e. Word ( Vtx ` G ) -> ( # ` w ) e. NN0 ) | 
						
							| 8 | 7 | nn0zd |  |-  ( w e. Word ( Vtx ` G ) -> ( # ` w ) e. ZZ ) | 
						
							| 9 |  | zgt0ge1 |  |-  ( ( # ` w ) e. ZZ -> ( 0 < ( # ` w ) <-> 1 <_ ( # ` w ) ) ) | 
						
							| 10 | 8 9 | syl |  |-  ( w e. Word ( Vtx ` G ) -> ( 0 < ( # ` w ) <-> 1 <_ ( # ` w ) ) ) | 
						
							| 11 | 10 | biimpd |  |-  ( w e. Word ( Vtx ` G ) -> ( 0 < ( # ` w ) -> 1 <_ ( # ` w ) ) ) | 
						
							| 12 | 11 | anc2li |  |-  ( w e. Word ( Vtx ` G ) -> ( 0 < ( # ` w ) -> ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) ) | 
						
							| 13 | 12 | 3ad2ant2 |  |-  ( ( G e. _V /\ w e. Word ( Vtx ` G ) /\ w =/= (/) ) -> ( 0 < ( # ` w ) -> ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) ) | 
						
							| 14 | 6 13 | syl |  |-  ( w e. ( ClWWalks ` G ) -> ( 0 < ( # ` w ) -> ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) ) | 
						
							| 15 | 4 14 | mpd |  |-  ( w e. ( ClWWalks ` G ) -> ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) | 
						
							| 16 | 15 | adantl |  |-  ( ( G e. USPGraph /\ w e. ( ClWWalks ` G ) ) -> ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) | 
						
							| 17 |  | eqid |  |-  ( iEdg ` G ) = ( iEdg ` G ) | 
						
							| 18 | 5 17 | clwlkclwwlk2 |  |-  ( ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( E. f f ( ClWalks ` G ) ( w ++ <" ( w ` 0 ) "> ) <-> w e. ( ClWWalks ` G ) ) ) | 
						
							| 19 |  | df-br |  |-  ( f ( ClWalks ` G ) ( w ++ <" ( w ` 0 ) "> ) <-> <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) | 
						
							| 20 |  | simpr2 |  |-  ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) /\ ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) -> w e. Word ( Vtx ` G ) ) | 
						
							| 21 |  | simpr3 |  |-  ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) /\ ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) -> 1 <_ ( # ` w ) ) | 
						
							| 22 |  | simpl |  |-  ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) /\ ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) -> <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) | 
						
							| 23 | 1 | clwlkclwwlkfolem |  |-  ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. C ) | 
						
							| 24 | 20 21 22 23 | syl3anc |  |-  ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) /\ ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) -> <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. C ) | 
						
							| 25 | 23 | 3expa |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. C ) | 
						
							| 26 |  | ovex |  |-  ( ( w ++ <" ( w ` 0 ) "> ) prefix ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) ) e. _V | 
						
							| 27 |  | fveq2 |  |-  ( c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. -> ( 2nd ` c ) = ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) | 
						
							| 28 |  | 2fveq3 |  |-  ( c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. -> ( # ` ( 2nd ` c ) ) = ( # ` ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) ) | 
						
							| 29 | 28 | oveq1d |  |-  ( c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. -> ( ( # ` ( 2nd ` c ) ) - 1 ) = ( ( # ` ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) - 1 ) ) | 
						
							| 30 | 27 29 | oveq12d |  |-  ( c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. -> ( ( 2nd ` c ) prefix ( ( # ` ( 2nd ` c ) ) - 1 ) ) = ( ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) prefix ( ( # ` ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) - 1 ) ) ) | 
						
							| 31 |  | vex |  |-  f e. _V | 
						
							| 32 |  | ovex |  |-  ( w ++ <" ( w ` 0 ) "> ) e. _V | 
						
							| 33 | 31 32 | op2nd |  |-  ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) = ( w ++ <" ( w ` 0 ) "> ) | 
						
							| 34 | 33 | fveq2i |  |-  ( # ` ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) = ( # ` ( w ++ <" ( w ` 0 ) "> ) ) | 
						
							| 35 | 34 | oveq1i |  |-  ( ( # ` ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) - 1 ) = ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) | 
						
							| 36 | 33 35 | oveq12i |  |-  ( ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) prefix ( ( # ` ( 2nd ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) - 1 ) ) = ( ( w ++ <" ( w ` 0 ) "> ) prefix ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) ) | 
						
							| 37 | 30 36 | eqtrdi |  |-  ( c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. -> ( ( 2nd ` c ) prefix ( ( # ` ( 2nd ` c ) ) - 1 ) ) = ( ( w ++ <" ( w ` 0 ) "> ) prefix ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) ) ) | 
						
							| 38 | 37 2 | fvmptg |  |-  ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. C /\ ( ( w ++ <" ( w ` 0 ) "> ) prefix ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) ) e. _V ) -> ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) = ( ( w ++ <" ( w ` 0 ) "> ) prefix ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) ) ) | 
						
							| 39 | 25 26 38 | sylancl |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) = ( ( w ++ <" ( w ` 0 ) "> ) prefix ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) ) ) | 
						
							| 40 |  | wrdlenccats1lenm1 |  |-  ( w e. Word ( Vtx ` G ) -> ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) = ( # ` w ) ) | 
						
							| 41 | 40 | ad2antrr |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) = ( # ` w ) ) | 
						
							| 42 | 41 | oveq2d |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> ( ( w ++ <" ( w ` 0 ) "> ) prefix ( ( # ` ( w ++ <" ( w ` 0 ) "> ) ) - 1 ) ) = ( ( w ++ <" ( w ` 0 ) "> ) prefix ( # ` w ) ) ) | 
						
							| 43 |  | simpll |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> w e. Word ( Vtx ` G ) ) | 
						
							| 44 |  | simpl |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) | 
						
							| 45 |  | wrdsymb1 |  |-  ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( w ` 0 ) e. ( Vtx ` G ) ) | 
						
							| 46 | 44 45 | syl |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> ( w ` 0 ) e. ( Vtx ` G ) ) | 
						
							| 47 | 46 | s1cld |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> <" ( w ` 0 ) "> e. Word ( Vtx ` G ) ) | 
						
							| 48 |  | eqidd |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> ( # ` w ) = ( # ` w ) ) | 
						
							| 49 |  | pfxccatid |  |-  ( ( w e. Word ( Vtx ` G ) /\ <" ( w ` 0 ) "> e. Word ( Vtx ` G ) /\ ( # ` w ) = ( # ` w ) ) -> ( ( w ++ <" ( w ` 0 ) "> ) prefix ( # ` w ) ) = w ) | 
						
							| 50 | 43 47 48 49 | syl3anc |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> ( ( w ++ <" ( w ` 0 ) "> ) prefix ( # ` w ) ) = w ) | 
						
							| 51 | 39 42 50 | 3eqtrrd |  |-  ( ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) /\ <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) ) -> w = ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) | 
						
							| 52 | 51 | ex |  |-  ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> w = ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) ) | 
						
							| 53 | 52 | 3adant1 |  |-  ( ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> w = ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) ) | 
						
							| 54 | 53 | ad2antlr |  |-  ( ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) /\ ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) /\ c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) -> ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> w = ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) ) | 
						
							| 55 |  | fveq2 |  |-  ( c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. -> ( F ` c ) = ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) | 
						
							| 56 | 55 | eqeq2d |  |-  ( c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. -> ( w = ( F ` c ) <-> w = ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) ) | 
						
							| 57 | 56 | imbi2d |  |-  ( c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. -> ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> w = ( F ` c ) ) <-> ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> w = ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) ) ) | 
						
							| 58 | 57 | adantl |  |-  ( ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) /\ ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) /\ c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) -> ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> w = ( F ` c ) ) <-> ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> w = ( F ` <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) ) ) ) | 
						
							| 59 | 54 58 | mpbird |  |-  ( ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) /\ ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) /\ c = <. f , ( w ++ <" ( w ` 0 ) "> ) >. ) -> ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> w = ( F ` c ) ) ) | 
						
							| 60 | 24 59 | rspcimedv |  |-  ( ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) /\ ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) ) -> ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> E. c e. C w = ( F ` c ) ) ) | 
						
							| 61 | 60 | ex |  |-  ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> ( ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> E. c e. C w = ( F ` c ) ) ) ) | 
						
							| 62 | 61 | pm2.43b |  |-  ( ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( <. f , ( w ++ <" ( w ` 0 ) "> ) >. e. ( ClWalks ` G ) -> E. c e. C w = ( F ` c ) ) ) | 
						
							| 63 | 19 62 | biimtrid |  |-  ( ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( f ( ClWalks ` G ) ( w ++ <" ( w ` 0 ) "> ) -> E. c e. C w = ( F ` c ) ) ) | 
						
							| 64 | 63 | exlimdv |  |-  ( ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( E. f f ( ClWalks ` G ) ( w ++ <" ( w ` 0 ) "> ) -> E. c e. C w = ( F ` c ) ) ) | 
						
							| 65 | 18 64 | sylbird |  |-  ( ( G e. USPGraph /\ w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( w e. ( ClWWalks ` G ) -> E. c e. C w = ( F ` c ) ) ) | 
						
							| 66 | 65 | 3expib |  |-  ( G e. USPGraph -> ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> ( w e. ( ClWWalks ` G ) -> E. c e. C w = ( F ` c ) ) ) ) | 
						
							| 67 | 66 | com23 |  |-  ( G e. USPGraph -> ( w e. ( ClWWalks ` G ) -> ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> E. c e. C w = ( F ` c ) ) ) ) | 
						
							| 68 | 67 | imp |  |-  ( ( G e. USPGraph /\ w e. ( ClWWalks ` G ) ) -> ( ( w e. Word ( Vtx ` G ) /\ 1 <_ ( # ` w ) ) -> E. c e. C w = ( F ` c ) ) ) | 
						
							| 69 | 16 68 | mpd |  |-  ( ( G e. USPGraph /\ w e. ( ClWWalks ` G ) ) -> E. c e. C w = ( F ` c ) ) | 
						
							| 70 | 69 | ralrimiva |  |-  ( G e. USPGraph -> A. w e. ( ClWWalks ` G ) E. c e. C w = ( F ` c ) ) | 
						
							| 71 |  | dffo3 |  |-  ( F : C -onto-> ( ClWWalks ` G ) <-> ( F : C --> ( ClWWalks ` G ) /\ A. w e. ( ClWWalks ` G ) E. c e. C w = ( F ` c ) ) ) | 
						
							| 72 | 3 70 71 | sylanbrc |  |-  ( G e. USPGraph -> F : C -onto-> ( ClWWalks ` G ) ) |