| 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 |  | fviss |  |-  ( _I ` Word ( I X. 2o ) ) C_ Word ( I X. 2o ) | 
						
							| 6 | 1 5 | eqsstri |  |-  W C_ Word ( I X. 2o ) | 
						
							| 7 |  | simpl |  |-  ( ( X e. W /\ ( a e. ( 0 ... ( # ` X ) ) /\ b e. ( I X. 2o ) ) ) -> X e. W ) | 
						
							| 8 | 6 7 | sselid |  |-  ( ( X e. W /\ ( a e. ( 0 ... ( # ` X ) ) /\ b e. ( I X. 2o ) ) ) -> X e. Word ( I X. 2o ) ) | 
						
							| 9 |  | simprr |  |-  ( ( X e. W /\ ( a e. ( 0 ... ( # ` X ) ) /\ b e. ( I X. 2o ) ) ) -> b e. ( I X. 2o ) ) | 
						
							| 10 | 3 | efgmf |  |-  M : ( I X. 2o ) --> ( I X. 2o ) | 
						
							| 11 | 10 | ffvelcdmi |  |-  ( b e. ( I X. 2o ) -> ( M ` b ) e. ( I X. 2o ) ) | 
						
							| 12 | 11 | ad2antll |  |-  ( ( X e. W /\ ( a e. ( 0 ... ( # ` X ) ) /\ b e. ( I X. 2o ) ) ) -> ( M ` b ) e. ( I X. 2o ) ) | 
						
							| 13 | 9 12 | s2cld |  |-  ( ( X e. W /\ ( a e. ( 0 ... ( # ` X ) ) /\ b e. ( I X. 2o ) ) ) -> <" b ( M ` b ) "> e. Word ( I X. 2o ) ) | 
						
							| 14 |  | splcl |  |-  ( ( X e. Word ( I X. 2o ) /\ <" b ( M ` b ) "> e. Word ( I X. 2o ) ) -> ( X splice <. a , a , <" b ( M ` b ) "> >. ) e. Word ( I X. 2o ) ) | 
						
							| 15 | 8 13 14 | syl2anc |  |-  ( ( X e. W /\ ( a e. ( 0 ... ( # ` X ) ) /\ b e. ( I X. 2o ) ) ) -> ( X splice <. a , a , <" b ( M ` b ) "> >. ) e. Word ( I X. 2o ) ) | 
						
							| 16 | 1 | efgrcl |  |-  ( X e. W -> ( I e. _V /\ W = Word ( I X. 2o ) ) ) | 
						
							| 17 | 16 | simprd |  |-  ( X e. W -> W = Word ( I X. 2o ) ) | 
						
							| 18 | 17 | adantr |  |-  ( ( X e. W /\ ( a e. ( 0 ... ( # ` X ) ) /\ b e. ( I X. 2o ) ) ) -> W = Word ( I X. 2o ) ) | 
						
							| 19 | 15 18 | eleqtrrd |  |-  ( ( X e. W /\ ( a e. ( 0 ... ( # ` X ) ) /\ b e. ( I X. 2o ) ) ) -> ( X splice <. a , a , <" b ( M ` b ) "> >. ) e. W ) | 
						
							| 20 | 19 | ralrimivva |  |-  ( X e. W -> A. a e. ( 0 ... ( # ` X ) ) A. b e. ( I X. 2o ) ( X splice <. a , a , <" b ( M ` b ) "> >. ) e. W ) | 
						
							| 21 |  | eqid |  |-  ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) = ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) | 
						
							| 22 | 21 | fmpo |  |-  ( A. a e. ( 0 ... ( # ` X ) ) A. b e. ( I X. 2o ) ( X splice <. a , a , <" b ( M ` b ) "> >. ) e. W <-> ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) : ( ( 0 ... ( # ` X ) ) X. ( I X. 2o ) ) --> W ) | 
						
							| 23 | 20 22 | sylib |  |-  ( X e. W -> ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) : ( ( 0 ... ( # ` X ) ) X. ( I X. 2o ) ) --> W ) | 
						
							| 24 |  | ovex |  |-  ( 0 ... ( # ` X ) ) e. _V | 
						
							| 25 | 16 | simpld |  |-  ( X e. W -> I e. _V ) | 
						
							| 26 |  | 2on |  |-  2o e. On | 
						
							| 27 |  | xpexg |  |-  ( ( I e. _V /\ 2o e. On ) -> ( I X. 2o ) e. _V ) | 
						
							| 28 | 25 26 27 | sylancl |  |-  ( X e. W -> ( I X. 2o ) e. _V ) | 
						
							| 29 |  | xpexg |  |-  ( ( ( 0 ... ( # ` X ) ) e. _V /\ ( I X. 2o ) e. _V ) -> ( ( 0 ... ( # ` X ) ) X. ( I X. 2o ) ) e. _V ) | 
						
							| 30 | 24 28 29 | sylancr |  |-  ( X e. W -> ( ( 0 ... ( # ` X ) ) X. ( I X. 2o ) ) e. _V ) | 
						
							| 31 | 23 30 | fexd |  |-  ( X e. W -> ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) e. _V ) | 
						
							| 32 |  | fveq2 |  |-  ( u = X -> ( # ` u ) = ( # ` X ) ) | 
						
							| 33 | 32 | oveq2d |  |-  ( u = X -> ( 0 ... ( # ` u ) ) = ( 0 ... ( # ` X ) ) ) | 
						
							| 34 |  | eqidd |  |-  ( u = X -> ( I X. 2o ) = ( I X. 2o ) ) | 
						
							| 35 |  | oveq1 |  |-  ( u = X -> ( u splice <. a , a , <" b ( M ` b ) "> >. ) = ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) | 
						
							| 36 | 33 34 35 | mpoeq123dv |  |-  ( u = X -> ( a e. ( 0 ... ( # ` u ) ) , b e. ( I X. 2o ) |-> ( u splice <. a , a , <" b ( M ` b ) "> >. ) ) = ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) ) | 
						
							| 37 |  | oteq1 |  |-  ( n = a -> <. n , n , <" w ( M ` w ) "> >. = <. a , n , <" w ( M ` w ) "> >. ) | 
						
							| 38 |  | oteq2 |  |-  ( n = a -> <. a , n , <" w ( M ` w ) "> >. = <. a , a , <" w ( M ` w ) "> >. ) | 
						
							| 39 | 37 38 | eqtrd |  |-  ( n = a -> <. n , n , <" w ( M ` w ) "> >. = <. a , a , <" w ( M ` w ) "> >. ) | 
						
							| 40 | 39 | oveq2d |  |-  ( n = a -> ( v splice <. n , n , <" w ( M ` w ) "> >. ) = ( v splice <. a , a , <" w ( M ` w ) "> >. ) ) | 
						
							| 41 |  | id |  |-  ( w = b -> w = b ) | 
						
							| 42 |  | fveq2 |  |-  ( w = b -> ( M ` w ) = ( M ` b ) ) | 
						
							| 43 | 41 42 | s2eqd |  |-  ( w = b -> <" w ( M ` w ) "> = <" b ( M ` b ) "> ) | 
						
							| 44 | 43 | oteq3d |  |-  ( w = b -> <. a , a , <" w ( M ` w ) "> >. = <. a , a , <" b ( M ` b ) "> >. ) | 
						
							| 45 | 44 | oveq2d |  |-  ( w = b -> ( v splice <. a , a , <" w ( M ` w ) "> >. ) = ( v splice <. a , a , <" b ( M ` b ) "> >. ) ) | 
						
							| 46 | 40 45 | cbvmpov |  |-  ( n e. ( 0 ... ( # ` v ) ) , w e. ( I X. 2o ) |-> ( v splice <. n , n , <" w ( M ` w ) "> >. ) ) = ( a e. ( 0 ... ( # ` v ) ) , b e. ( I X. 2o ) |-> ( v splice <. a , a , <" b ( M ` b ) "> >. ) ) | 
						
							| 47 |  | fveq2 |  |-  ( v = u -> ( # ` v ) = ( # ` u ) ) | 
						
							| 48 | 47 | oveq2d |  |-  ( v = u -> ( 0 ... ( # ` v ) ) = ( 0 ... ( # ` u ) ) ) | 
						
							| 49 |  | eqidd |  |-  ( v = u -> ( I X. 2o ) = ( I X. 2o ) ) | 
						
							| 50 |  | oveq1 |  |-  ( v = u -> ( v splice <. a , a , <" b ( M ` b ) "> >. ) = ( u splice <. a , a , <" b ( M ` b ) "> >. ) ) | 
						
							| 51 | 48 49 50 | mpoeq123dv |  |-  ( v = u -> ( a e. ( 0 ... ( # ` v ) ) , b e. ( I X. 2o ) |-> ( v splice <. a , a , <" b ( M ` b ) "> >. ) ) = ( a e. ( 0 ... ( # ` u ) ) , b e. ( I X. 2o ) |-> ( u splice <. a , a , <" b ( M ` b ) "> >. ) ) ) | 
						
							| 52 | 46 51 | eqtrid |  |-  ( v = u -> ( n e. ( 0 ... ( # ` v ) ) , w e. ( I X. 2o ) |-> ( v splice <. n , n , <" w ( M ` w ) "> >. ) ) = ( a e. ( 0 ... ( # ` u ) ) , b e. ( I X. 2o ) |-> ( u splice <. a , a , <" b ( M ` b ) "> >. ) ) ) | 
						
							| 53 | 52 | cbvmptv |  |-  ( v e. W |-> ( n e. ( 0 ... ( # ` v ) ) , w e. ( I X. 2o ) |-> ( v splice <. n , n , <" w ( M ` w ) "> >. ) ) ) = ( u e. W |-> ( a e. ( 0 ... ( # ` u ) ) , b e. ( I X. 2o ) |-> ( u splice <. a , a , <" b ( M ` b ) "> >. ) ) ) | 
						
							| 54 | 4 53 | eqtri |  |-  T = ( u e. W |-> ( a e. ( 0 ... ( # ` u ) ) , b e. ( I X. 2o ) |-> ( u splice <. a , a , <" b ( M ` b ) "> >. ) ) ) | 
						
							| 55 | 36 54 | fvmptg |  |-  ( ( X e. W /\ ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) e. _V ) -> ( T ` X ) = ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) ) | 
						
							| 56 | 31 55 | mpdan |  |-  ( X e. W -> ( T ` X ) = ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) ) | 
						
							| 57 | 56 | feq1d |  |-  ( X e. W -> ( ( T ` X ) : ( ( 0 ... ( # ` X ) ) X. ( I X. 2o ) ) --> W <-> ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) : ( ( 0 ... ( # ` X ) ) X. ( I X. 2o ) ) --> W ) ) | 
						
							| 58 | 23 57 | mpbird |  |-  ( X e. W -> ( T ` X ) : ( ( 0 ... ( # ` X ) ) X. ( I X. 2o ) ) --> W ) | 
						
							| 59 | 56 58 | jca |  |-  ( X e. W -> ( ( T ` X ) = ( a e. ( 0 ... ( # ` X ) ) , b e. ( I X. 2o ) |-> ( X splice <. a , a , <" b ( M ` b ) "> >. ) ) /\ ( T ` X ) : ( ( 0 ... ( # ` X ) ) X. ( I X. 2o ) ) --> W ) ) |