| Step | Hyp | Ref | Expression | 
						
							| 1 |  | wlkiswwlks2lem.f |  |-  F = ( x e. ( 0 ..^ ( ( # ` P ) - 1 ) ) |-> ( `' E ` { ( P ` x ) , ( P ` ( x + 1 ) ) } ) ) | 
						
							| 2 |  | wlkiswwlks2lem.e |  |-  E = ( iEdg ` G ) | 
						
							| 3 | 2 | uspgrf1oedg |  |-  ( G e. USPGraph -> E : dom E -1-1-onto-> ( Edg ` G ) ) | 
						
							| 4 | 2 | rneqi |  |-  ran E = ran ( iEdg ` G ) | 
						
							| 5 |  | edgval |  |-  ( Edg ` G ) = ran ( iEdg ` G ) | 
						
							| 6 | 4 5 | eqtr4i |  |-  ran E = ( Edg ` G ) | 
						
							| 7 | 6 | a1i |  |-  ( G e. USPGraph -> ran E = ( Edg ` G ) ) | 
						
							| 8 | 7 | f1oeq3d |  |-  ( G e. USPGraph -> ( E : dom E -1-1-onto-> ran E <-> E : dom E -1-1-onto-> ( Edg ` G ) ) ) | 
						
							| 9 | 3 8 | mpbird |  |-  ( G e. USPGraph -> E : dom E -1-1-onto-> ran E ) | 
						
							| 10 | 9 | 3ad2ant1 |  |-  ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) -> E : dom E -1-1-onto-> ran E ) | 
						
							| 11 | 10 | ad2antrr |  |-  ( ( ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) /\ A. i e. ( 0 ..^ ( ( # ` P ) - 1 ) ) { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E ) /\ x e. ( 0 ..^ ( ( # ` P ) - 1 ) ) ) -> E : dom E -1-1-onto-> ran E ) | 
						
							| 12 |  | simpr |  |-  ( ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) /\ x e. ( 0 ..^ ( ( # ` P ) - 1 ) ) ) -> x e. ( 0 ..^ ( ( # ` P ) - 1 ) ) ) | 
						
							| 13 |  | fveq2 |  |-  ( i = x -> ( P ` i ) = ( P ` x ) ) | 
						
							| 14 |  | fvoveq1 |  |-  ( i = x -> ( P ` ( i + 1 ) ) = ( P ` ( x + 1 ) ) ) | 
						
							| 15 | 13 14 | preq12d |  |-  ( i = x -> { ( P ` i ) , ( P ` ( i + 1 ) ) } = { ( P ` x ) , ( P ` ( x + 1 ) ) } ) | 
						
							| 16 | 15 | eleq1d |  |-  ( i = x -> ( { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E <-> { ( P ` x ) , ( P ` ( x + 1 ) ) } e. ran E ) ) | 
						
							| 17 | 16 | adantl |  |-  ( ( ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) /\ x e. ( 0 ..^ ( ( # ` P ) - 1 ) ) ) /\ i = x ) -> ( { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E <-> { ( P ` x ) , ( P ` ( x + 1 ) ) } e. ran E ) ) | 
						
							| 18 | 12 17 | rspcdv |  |-  ( ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) /\ x e. ( 0 ..^ ( ( # ` P ) - 1 ) ) ) -> ( A. i e. ( 0 ..^ ( ( # ` P ) - 1 ) ) { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E -> { ( P ` x ) , ( P ` ( x + 1 ) ) } e. ran E ) ) | 
						
							| 19 | 18 | impancom |  |-  ( ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) /\ A. i e. ( 0 ..^ ( ( # ` P ) - 1 ) ) { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E ) -> ( x e. ( 0 ..^ ( ( # ` P ) - 1 ) ) -> { ( P ` x ) , ( P ` ( x + 1 ) ) } e. ran E ) ) | 
						
							| 20 | 19 | imp |  |-  ( ( ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) /\ A. i e. ( 0 ..^ ( ( # ` P ) - 1 ) ) { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E ) /\ x e. ( 0 ..^ ( ( # ` P ) - 1 ) ) ) -> { ( P ` x ) , ( P ` ( x + 1 ) ) } e. ran E ) | 
						
							| 21 |  | f1ocnvdm |  |-  ( ( E : dom E -1-1-onto-> ran E /\ { ( P ` x ) , ( P ` ( x + 1 ) ) } e. ran E ) -> ( `' E ` { ( P ` x ) , ( P ` ( x + 1 ) ) } ) e. dom E ) | 
						
							| 22 | 11 20 21 | syl2anc |  |-  ( ( ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) /\ A. i e. ( 0 ..^ ( ( # ` P ) - 1 ) ) { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E ) /\ x e. ( 0 ..^ ( ( # ` P ) - 1 ) ) ) -> ( `' E ` { ( P ` x ) , ( P ` ( x + 1 ) ) } ) e. dom E ) | 
						
							| 23 | 22 1 | fmptd |  |-  ( ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) /\ A. i e. ( 0 ..^ ( ( # ` P ) - 1 ) ) { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E ) -> F : ( 0 ..^ ( ( # ` P ) - 1 ) ) --> dom E ) | 
						
							| 24 |  | iswrdi |  |-  ( F : ( 0 ..^ ( ( # ` P ) - 1 ) ) --> dom E -> F e. Word dom E ) | 
						
							| 25 | 23 24 | syl |  |-  ( ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) /\ A. i e. ( 0 ..^ ( ( # ` P ) - 1 ) ) { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E ) -> F e. Word dom E ) | 
						
							| 26 | 25 | ex |  |-  ( ( G e. USPGraph /\ P e. Word V /\ 1 <_ ( # ` P ) ) -> ( A. i e. ( 0 ..^ ( ( # ` P ) - 1 ) ) { ( P ` i ) , ( P ` ( i + 1 ) ) } e. ran E -> F e. Word dom E ) ) |