| Step | Hyp | Ref | Expression | 
						
							| 1 |  | efgval.w |  |-  W = ( _I ` Word ( I X. 2o ) ) | 
						
							| 2 |  | efgval.r |  |-  .~ = ( ~FG ` I ) | 
						
							| 3 |  | efgval2.m |  |-  M = ( y e. I , z e. 2o |-> <. y , ( 1o \ z ) >. ) | 
						
							| 4 |  | efgval2.t |  |-  T = ( v e. W |-> ( n e. ( 0 ... ( # ` v ) ) , w e. ( I X. 2o ) |-> ( v splice <. n , n , <" w ( M ` w ) "> >. ) ) ) | 
						
							| 5 |  | efgred.d |  |-  D = ( W \ U_ x e. W ran ( T ` x ) ) | 
						
							| 6 |  | efgred.s |  |-  S = ( m e. { t e. ( Word W \ { (/) } ) | ( ( t ` 0 ) e. D /\ A. k e. ( 1 ..^ ( # ` t ) ) ( t ` k ) e. ran ( T ` ( t ` ( k - 1 ) ) ) ) } |-> ( m ` ( ( # ` m ) - 1 ) ) ) | 
						
							| 7 | 1 2 3 4 5 6 | efgsdm |  |-  ( F e. dom S <-> ( F e. ( Word W \ { (/) } ) /\ ( F ` 0 ) e. D /\ A. a e. ( 1 ..^ ( # ` F ) ) ( F ` a ) e. ran ( T ` ( F ` ( a - 1 ) ) ) ) ) | 
						
							| 8 | 7 | simp1bi |  |-  ( F e. dom S -> F e. ( Word W \ { (/) } ) ) | 
						
							| 9 |  | eldifsn |  |-  ( F e. ( Word W \ { (/) } ) <-> ( F e. Word W /\ F =/= (/) ) ) | 
						
							| 10 |  | lennncl |  |-  ( ( F e. Word W /\ F =/= (/) ) -> ( # ` F ) e. NN ) | 
						
							| 11 | 9 10 | sylbi |  |-  ( F e. ( Word W \ { (/) } ) -> ( # ` F ) e. NN ) | 
						
							| 12 |  | fzo0end |  |-  ( ( # ` F ) e. NN -> ( ( # ` F ) - 1 ) e. ( 0 ..^ ( # ` F ) ) ) | 
						
							| 13 | 8 11 12 | 3syl |  |-  ( F e. dom S -> ( ( # ` F ) - 1 ) e. ( 0 ..^ ( # ` F ) ) ) | 
						
							| 14 |  | nnm1nn0 |  |-  ( ( # ` F ) e. NN -> ( ( # ` F ) - 1 ) e. NN0 ) | 
						
							| 15 | 8 11 14 | 3syl |  |-  ( F e. dom S -> ( ( # ` F ) - 1 ) e. NN0 ) | 
						
							| 16 |  | eleq1 |  |-  ( a = 0 -> ( a e. ( 0 ..^ ( # ` F ) ) <-> 0 e. ( 0 ..^ ( # ` F ) ) ) ) | 
						
							| 17 |  | fveq2 |  |-  ( a = 0 -> ( F ` a ) = ( F ` 0 ) ) | 
						
							| 18 | 17 | breq2d |  |-  ( a = 0 -> ( ( F ` 0 ) .~ ( F ` a ) <-> ( F ` 0 ) .~ ( F ` 0 ) ) ) | 
						
							| 19 | 16 18 | imbi12d |  |-  ( a = 0 -> ( ( a e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` a ) ) <-> ( 0 e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` 0 ) ) ) ) | 
						
							| 20 | 19 | imbi2d |  |-  ( a = 0 -> ( ( F e. dom S -> ( a e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` a ) ) ) <-> ( F e. dom S -> ( 0 e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` 0 ) ) ) ) ) | 
						
							| 21 |  | eleq1 |  |-  ( a = i -> ( a e. ( 0 ..^ ( # ` F ) ) <-> i e. ( 0 ..^ ( # ` F ) ) ) ) | 
						
							| 22 |  | fveq2 |  |-  ( a = i -> ( F ` a ) = ( F ` i ) ) | 
						
							| 23 | 22 | breq2d |  |-  ( a = i -> ( ( F ` 0 ) .~ ( F ` a ) <-> ( F ` 0 ) .~ ( F ` i ) ) ) | 
						
							| 24 | 21 23 | imbi12d |  |-  ( a = i -> ( ( a e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` a ) ) <-> ( i e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` i ) ) ) ) | 
						
							| 25 | 24 | imbi2d |  |-  ( a = i -> ( ( F e. dom S -> ( a e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` a ) ) ) <-> ( F e. dom S -> ( i e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` i ) ) ) ) ) | 
						
							| 26 |  | eleq1 |  |-  ( a = ( i + 1 ) -> ( a e. ( 0 ..^ ( # ` F ) ) <-> ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) ) | 
						
							| 27 |  | fveq2 |  |-  ( a = ( i + 1 ) -> ( F ` a ) = ( F ` ( i + 1 ) ) ) | 
						
							| 28 | 27 | breq2d |  |-  ( a = ( i + 1 ) -> ( ( F ` 0 ) .~ ( F ` a ) <-> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) | 
						
							| 29 | 26 28 | imbi12d |  |-  ( a = ( i + 1 ) -> ( ( a e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` a ) ) <-> ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) ) | 
						
							| 30 | 29 | imbi2d |  |-  ( a = ( i + 1 ) -> ( ( F e. dom S -> ( a e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` a ) ) ) <-> ( F e. dom S -> ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) ) ) | 
						
							| 31 |  | eleq1 |  |-  ( a = ( ( # ` F ) - 1 ) -> ( a e. ( 0 ..^ ( # ` F ) ) <-> ( ( # ` F ) - 1 ) e. ( 0 ..^ ( # ` F ) ) ) ) | 
						
							| 32 |  | fveq2 |  |-  ( a = ( ( # ` F ) - 1 ) -> ( F ` a ) = ( F ` ( ( # ` F ) - 1 ) ) ) | 
						
							| 33 | 32 | breq2d |  |-  ( a = ( ( # ` F ) - 1 ) -> ( ( F ` 0 ) .~ ( F ` a ) <-> ( F ` 0 ) .~ ( F ` ( ( # ` F ) - 1 ) ) ) ) | 
						
							| 34 | 31 33 | imbi12d |  |-  ( a = ( ( # ` F ) - 1 ) -> ( ( a e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` a ) ) <-> ( ( ( # ` F ) - 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( ( # ` F ) - 1 ) ) ) ) ) | 
						
							| 35 | 34 | imbi2d |  |-  ( a = ( ( # ` F ) - 1 ) -> ( ( F e. dom S -> ( a e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` a ) ) ) <-> ( F e. dom S -> ( ( ( # ` F ) - 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( ( # ` F ) - 1 ) ) ) ) ) ) | 
						
							| 36 | 1 2 | efger |  |-  .~ Er W | 
						
							| 37 | 36 | a1i |  |-  ( ( F e. dom S /\ 0 e. ( 0 ..^ ( # ` F ) ) ) -> .~ Er W ) | 
						
							| 38 |  | eldifi |  |-  ( F e. ( Word W \ { (/) } ) -> F e. Word W ) | 
						
							| 39 |  | wrdf |  |-  ( F e. Word W -> F : ( 0 ..^ ( # ` F ) ) --> W ) | 
						
							| 40 | 8 38 39 | 3syl |  |-  ( F e. dom S -> F : ( 0 ..^ ( # ` F ) ) --> W ) | 
						
							| 41 | 40 | ffvelcdmda |  |-  ( ( F e. dom S /\ 0 e. ( 0 ..^ ( # ` F ) ) ) -> ( F ` 0 ) e. W ) | 
						
							| 42 | 37 41 | erref |  |-  ( ( F e. dom S /\ 0 e. ( 0 ..^ ( # ` F ) ) ) -> ( F ` 0 ) .~ ( F ` 0 ) ) | 
						
							| 43 | 42 | ex |  |-  ( F e. dom S -> ( 0 e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` 0 ) ) ) | 
						
							| 44 |  | elnn0uz |  |-  ( i e. NN0 <-> i e. ( ZZ>= ` 0 ) ) | 
						
							| 45 |  | peano2fzor |  |-  ( ( i e. ( ZZ>= ` 0 ) /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> i e. ( 0 ..^ ( # ` F ) ) ) | 
						
							| 46 | 44 45 | sylanb |  |-  ( ( i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> i e. ( 0 ..^ ( # ` F ) ) ) | 
						
							| 47 | 46 | 3adant1 |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> i e. ( 0 ..^ ( # ` F ) ) ) | 
						
							| 48 | 47 | 3expia |  |-  ( ( F e. dom S /\ i e. NN0 ) -> ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> i e. ( 0 ..^ ( # ` F ) ) ) ) | 
						
							| 49 | 48 | imim1d |  |-  ( ( F e. dom S /\ i e. NN0 ) -> ( ( i e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` i ) ) -> ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` i ) ) ) ) | 
						
							| 50 | 40 | 3ad2ant1 |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> F : ( 0 ..^ ( # ` F ) ) --> W ) | 
						
							| 51 | 50 47 | ffvelcdmd |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( F ` i ) e. W ) | 
						
							| 52 |  | fvoveq1 |  |-  ( a = ( i + 1 ) -> ( F ` ( a - 1 ) ) = ( F ` ( ( i + 1 ) - 1 ) ) ) | 
						
							| 53 | 52 | fveq2d |  |-  ( a = ( i + 1 ) -> ( T ` ( F ` ( a - 1 ) ) ) = ( T ` ( F ` ( ( i + 1 ) - 1 ) ) ) ) | 
						
							| 54 | 53 | rneqd |  |-  ( a = ( i + 1 ) -> ran ( T ` ( F ` ( a - 1 ) ) ) = ran ( T ` ( F ` ( ( i + 1 ) - 1 ) ) ) ) | 
						
							| 55 | 27 54 | eleq12d |  |-  ( a = ( i + 1 ) -> ( ( F ` a ) e. ran ( T ` ( F ` ( a - 1 ) ) ) <-> ( F ` ( i + 1 ) ) e. ran ( T ` ( F ` ( ( i + 1 ) - 1 ) ) ) ) ) | 
						
							| 56 | 7 | simp3bi |  |-  ( F e. dom S -> A. a e. ( 1 ..^ ( # ` F ) ) ( F ` a ) e. ran ( T ` ( F ` ( a - 1 ) ) ) ) | 
						
							| 57 | 56 | 3ad2ant1 |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> A. a e. ( 1 ..^ ( # ` F ) ) ( F ` a ) e. ran ( T ` ( F ` ( a - 1 ) ) ) ) | 
						
							| 58 |  | nn0p1nn |  |-  ( i e. NN0 -> ( i + 1 ) e. NN ) | 
						
							| 59 | 58 | 3ad2ant2 |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( i + 1 ) e. NN ) | 
						
							| 60 |  | nnuz |  |-  NN = ( ZZ>= ` 1 ) | 
						
							| 61 | 59 60 | eleqtrdi |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( i + 1 ) e. ( ZZ>= ` 1 ) ) | 
						
							| 62 |  | elfzolt2b |  |-  ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( i + 1 ) e. ( ( i + 1 ) ..^ ( # ` F ) ) ) | 
						
							| 63 | 62 | 3ad2ant3 |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( i + 1 ) e. ( ( i + 1 ) ..^ ( # ` F ) ) ) | 
						
							| 64 |  | elfzo3 |  |-  ( ( i + 1 ) e. ( 1 ..^ ( # ` F ) ) <-> ( ( i + 1 ) e. ( ZZ>= ` 1 ) /\ ( i + 1 ) e. ( ( i + 1 ) ..^ ( # ` F ) ) ) ) | 
						
							| 65 | 61 63 64 | sylanbrc |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( i + 1 ) e. ( 1 ..^ ( # ` F ) ) ) | 
						
							| 66 | 55 57 65 | rspcdva |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( F ` ( i + 1 ) ) e. ran ( T ` ( F ` ( ( i + 1 ) - 1 ) ) ) ) | 
						
							| 67 |  | nn0cn |  |-  ( i e. NN0 -> i e. CC ) | 
						
							| 68 | 67 | 3ad2ant2 |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> i e. CC ) | 
						
							| 69 |  | ax-1cn |  |-  1 e. CC | 
						
							| 70 |  | pncan |  |-  ( ( i e. CC /\ 1 e. CC ) -> ( ( i + 1 ) - 1 ) = i ) | 
						
							| 71 | 68 69 70 | sylancl |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( ( i + 1 ) - 1 ) = i ) | 
						
							| 72 | 71 | fveq2d |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( F ` ( ( i + 1 ) - 1 ) ) = ( F ` i ) ) | 
						
							| 73 | 72 | fveq2d |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( T ` ( F ` ( ( i + 1 ) - 1 ) ) ) = ( T ` ( F ` i ) ) ) | 
						
							| 74 | 73 | rneqd |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ran ( T ` ( F ` ( ( i + 1 ) - 1 ) ) ) = ran ( T ` ( F ` i ) ) ) | 
						
							| 75 | 66 74 | eleqtrd |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( F ` ( i + 1 ) ) e. ran ( T ` ( F ` i ) ) ) | 
						
							| 76 | 1 2 3 4 | efgi2 |  |-  ( ( ( F ` i ) e. W /\ ( F ` ( i + 1 ) ) e. ran ( T ` ( F ` i ) ) ) -> ( F ` i ) .~ ( F ` ( i + 1 ) ) ) | 
						
							| 77 | 51 75 76 | syl2anc |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( F ` i ) .~ ( F ` ( i + 1 ) ) ) | 
						
							| 78 | 36 | a1i |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> .~ Er W ) | 
						
							| 79 | 78 | ertr |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( ( ( F ` 0 ) .~ ( F ` i ) /\ ( F ` i ) .~ ( F ` ( i + 1 ) ) ) -> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) | 
						
							| 80 | 77 79 | mpan2d |  |-  ( ( F e. dom S /\ i e. NN0 /\ ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) ) -> ( ( F ` 0 ) .~ ( F ` i ) -> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) | 
						
							| 81 | 80 | 3expia |  |-  ( ( F e. dom S /\ i e. NN0 ) -> ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( ( F ` 0 ) .~ ( F ` i ) -> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) ) | 
						
							| 82 | 81 | a2d |  |-  ( ( F e. dom S /\ i e. NN0 ) -> ( ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` i ) ) -> ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) ) | 
						
							| 83 | 49 82 | syld |  |-  ( ( F e. dom S /\ i e. NN0 ) -> ( ( i e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` i ) ) -> ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) ) | 
						
							| 84 | 83 | expcom |  |-  ( i e. NN0 -> ( F e. dom S -> ( ( i e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` i ) ) -> ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) ) ) | 
						
							| 85 | 84 | a2d |  |-  ( i e. NN0 -> ( ( F e. dom S -> ( i e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` i ) ) ) -> ( F e. dom S -> ( ( i + 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( i + 1 ) ) ) ) ) ) | 
						
							| 86 | 20 25 30 35 43 85 | nn0ind |  |-  ( ( ( # ` F ) - 1 ) e. NN0 -> ( F e. dom S -> ( ( ( # ` F ) - 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( ( # ` F ) - 1 ) ) ) ) ) | 
						
							| 87 | 15 86 | mpcom |  |-  ( F e. dom S -> ( ( ( # ` F ) - 1 ) e. ( 0 ..^ ( # ` F ) ) -> ( F ` 0 ) .~ ( F ` ( ( # ` F ) - 1 ) ) ) ) | 
						
							| 88 | 13 87 | mpd |  |-  ( F e. dom S -> ( F ` 0 ) .~ ( F ` ( ( # ` F ) - 1 ) ) ) | 
						
							| 89 | 1 2 3 4 5 6 | efgsval |  |-  ( F e. dom S -> ( S ` F ) = ( F ` ( ( # ` F ) - 1 ) ) ) | 
						
							| 90 | 88 89 | breqtrrd |  |-  ( F e. dom S -> ( F ` 0 ) .~ ( S ` F ) ) |