| 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 |  | fviss |  |-  ( _I ` Word ( I X. 2o ) ) C_ Word ( I X. 2o ) | 
						
							| 8 | 1 7 | eqsstri |  |-  W C_ Word ( I X. 2o ) | 
						
							| 9 | 1 2 3 4 5 6 | efgsf |  |-  S : { t e. ( Word W \ { (/) } ) | ( ( t ` 0 ) e. D /\ A. k e. ( 1 ..^ ( # ` t ) ) ( t ` k ) e. ran ( T ` ( t ` ( k - 1 ) ) ) ) } --> W | 
						
							| 10 | 9 | fdmi |  |-  dom S = { t e. ( Word W \ { (/) } ) | ( ( t ` 0 ) e. D /\ A. k e. ( 1 ..^ ( # ` t ) ) ( t ` k ) e. ran ( T ` ( t ` ( k - 1 ) ) ) ) } | 
						
							| 11 | 10 | feq2i |  |-  ( S : dom S --> W <-> S : { t e. ( Word W \ { (/) } ) | ( ( t ` 0 ) e. D /\ A. k e. ( 1 ..^ ( # ` t ) ) ( t ` k ) e. ran ( T ` ( t ` ( k - 1 ) ) ) ) } --> W ) | 
						
							| 12 | 9 11 | mpbir |  |-  S : dom S --> W | 
						
							| 13 | 12 | ffvelcdmi |  |-  ( A e. dom S -> ( S ` A ) e. W ) | 
						
							| 14 | 13 | adantr |  |-  ( ( A e. dom S /\ B e. dom S ) -> ( S ` A ) e. W ) | 
						
							| 15 | 8 14 | sselid |  |-  ( ( A e. dom S /\ B e. dom S ) -> ( S ` A ) e. Word ( I X. 2o ) ) | 
						
							| 16 |  | lencl |  |-  ( ( S ` A ) e. Word ( I X. 2o ) -> ( # ` ( S ` A ) ) e. NN0 ) | 
						
							| 17 | 15 16 | syl |  |-  ( ( A e. dom S /\ B e. dom S ) -> ( # ` ( S ` A ) ) e. NN0 ) | 
						
							| 18 |  | peano2nn0 |  |-  ( ( # ` ( S ` A ) ) e. NN0 -> ( ( # ` ( S ` A ) ) + 1 ) e. NN0 ) | 
						
							| 19 | 17 18 | syl |  |-  ( ( A e. dom S /\ B e. dom S ) -> ( ( # ` ( S ` A ) ) + 1 ) e. NN0 ) | 
						
							| 20 |  | breq2 |  |-  ( c = 0 -> ( ( # ` ( S ` a ) ) < c <-> ( # ` ( S ` a ) ) < 0 ) ) | 
						
							| 21 | 20 | imbi1d |  |-  ( c = 0 -> ( ( ( # ` ( S ` a ) ) < c -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( # ` ( S ` a ) ) < 0 -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 22 | 21 | 2ralbidv |  |-  ( c = 0 -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < c -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < 0 -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 23 |  | breq2 |  |-  ( c = i -> ( ( # ` ( S ` a ) ) < c <-> ( # ` ( S ` a ) ) < i ) ) | 
						
							| 24 | 23 | imbi1d |  |-  ( c = i -> ( ( ( # ` ( S ` a ) ) < c -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 25 | 24 | 2ralbidv |  |-  ( c = i -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < c -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 26 |  | breq2 |  |-  ( c = ( i + 1 ) -> ( ( # ` ( S ` a ) ) < c <-> ( # ` ( S ` a ) ) < ( i + 1 ) ) ) | 
						
							| 27 | 26 | imbi1d |  |-  ( c = ( i + 1 ) -> ( ( ( # ` ( S ` a ) ) < c -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( # ` ( S ` a ) ) < ( i + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 28 | 27 | 2ralbidv |  |-  ( c = ( i + 1 ) -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < c -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( i + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 29 |  | breq2 |  |-  ( c = ( ( # ` ( S ` A ) ) + 1 ) -> ( ( # ` ( S ` a ) ) < c <-> ( # ` ( S ` a ) ) < ( ( # ` ( S ` A ) ) + 1 ) ) ) | 
						
							| 30 | 29 | imbi1d |  |-  ( c = ( ( # ` ( S ` A ) ) + 1 ) -> ( ( ( # ` ( S ` a ) ) < c -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( # ` ( S ` a ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 31 | 30 | 2ralbidv |  |-  ( c = ( ( # ` ( S ` A ) ) + 1 ) -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < c -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 32 | 12 | ffvelcdmi |  |-  ( a e. dom S -> ( S ` a ) e. W ) | 
						
							| 33 | 8 32 | sselid |  |-  ( a e. dom S -> ( S ` a ) e. Word ( I X. 2o ) ) | 
						
							| 34 |  | lencl |  |-  ( ( S ` a ) e. Word ( I X. 2o ) -> ( # ` ( S ` a ) ) e. NN0 ) | 
						
							| 35 | 33 34 | syl |  |-  ( a e. dom S -> ( # ` ( S ` a ) ) e. NN0 ) | 
						
							| 36 |  | nn0nlt0 |  |-  ( ( # ` ( S ` a ) ) e. NN0 -> -. ( # ` ( S ` a ) ) < 0 ) | 
						
							| 37 | 35 36 | syl |  |-  ( a e. dom S -> -. ( # ` ( S ` a ) ) < 0 ) | 
						
							| 38 | 37 | pm2.21d |  |-  ( a e. dom S -> ( ( # ` ( S ` a ) ) < 0 -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 39 | 38 | adantr |  |-  ( ( a e. dom S /\ b e. dom S ) -> ( ( # ` ( S ` a ) ) < 0 -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 40 | 39 | rgen2 |  |-  A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < 0 -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) | 
						
							| 41 |  | simpl1 |  |-  ( ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) -> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 42 |  | simpl3l |  |-  ( ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) -> ( # ` ( S ` c ) ) = i ) | 
						
							| 43 |  | breq2 |  |-  ( ( # ` ( S ` c ) ) = i -> ( ( # ` ( S ` a ) ) < ( # ` ( S ` c ) ) <-> ( # ` ( S ` a ) ) < i ) ) | 
						
							| 44 | 43 | imbi1d |  |-  ( ( # ` ( S ` c ) ) = i -> ( ( ( # ` ( S ` a ) ) < ( # ` ( S ` c ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 45 | 44 | 2ralbidv |  |-  ( ( # ` ( S ` c ) ) = i -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( # ` ( S ` c ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 46 | 42 45 | syl |  |-  ( ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( # ` ( S ` c ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 47 | 41 46 | mpbird |  |-  ( ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) -> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( # ` ( S ` c ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 48 |  | simpl2l |  |-  ( ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) -> c e. dom S ) | 
						
							| 49 |  | simpl2r |  |-  ( ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) -> d e. dom S ) | 
						
							| 50 |  | simpl3r |  |-  ( ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) -> ( S ` c ) = ( S ` d ) ) | 
						
							| 51 |  | simpr |  |-  ( ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) -> -. ( c ` 0 ) = ( d ` 0 ) ) | 
						
							| 52 | 1 2 3 4 5 6 47 48 49 50 51 | efgredlem |  |-  -. ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) | 
						
							| 53 |  | iman |  |-  ( ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) -> ( c ` 0 ) = ( d ` 0 ) ) <-> -. ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) /\ -. ( c ` 0 ) = ( d ` 0 ) ) ) | 
						
							| 54 | 52 53 | mpbir |  |-  ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) /\ ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) ) -> ( c ` 0 ) = ( d ` 0 ) ) | 
						
							| 55 | 54 | 3expia |  |-  ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) ) -> ( ( ( # ` ( S ` c ) ) = i /\ ( S ` c ) = ( S ` d ) ) -> ( c ` 0 ) = ( d ` 0 ) ) ) | 
						
							| 56 | 55 | expd |  |-  ( ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( c e. dom S /\ d e. dom S ) ) -> ( ( # ` ( S ` c ) ) = i -> ( ( S ` c ) = ( S ` d ) -> ( c ` 0 ) = ( d ` 0 ) ) ) ) | 
						
							| 57 | 56 | ralrimivva |  |-  ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) -> A. c e. dom S A. d e. dom S ( ( # ` ( S ` c ) ) = i -> ( ( S ` c ) = ( S ` d ) -> ( c ` 0 ) = ( d ` 0 ) ) ) ) | 
						
							| 58 |  | 2fveq3 |  |-  ( c = a -> ( # ` ( S ` c ) ) = ( # ` ( S ` a ) ) ) | 
						
							| 59 | 58 | eqeq1d |  |-  ( c = a -> ( ( # ` ( S ` c ) ) = i <-> ( # ` ( S ` a ) ) = i ) ) | 
						
							| 60 |  | fveqeq2 |  |-  ( c = a -> ( ( S ` c ) = ( S ` d ) <-> ( S ` a ) = ( S ` d ) ) ) | 
						
							| 61 |  | fveq1 |  |-  ( c = a -> ( c ` 0 ) = ( a ` 0 ) ) | 
						
							| 62 | 61 | eqeq1d |  |-  ( c = a -> ( ( c ` 0 ) = ( d ` 0 ) <-> ( a ` 0 ) = ( d ` 0 ) ) ) | 
						
							| 63 | 60 62 | imbi12d |  |-  ( c = a -> ( ( ( S ` c ) = ( S ` d ) -> ( c ` 0 ) = ( d ` 0 ) ) <-> ( ( S ` a ) = ( S ` d ) -> ( a ` 0 ) = ( d ` 0 ) ) ) ) | 
						
							| 64 | 59 63 | imbi12d |  |-  ( c = a -> ( ( ( # ` ( S ` c ) ) = i -> ( ( S ` c ) = ( S ` d ) -> ( c ` 0 ) = ( d ` 0 ) ) ) <-> ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` d ) -> ( a ` 0 ) = ( d ` 0 ) ) ) ) ) | 
						
							| 65 |  | fveq2 |  |-  ( d = b -> ( S ` d ) = ( S ` b ) ) | 
						
							| 66 | 65 | eqeq2d |  |-  ( d = b -> ( ( S ` a ) = ( S ` d ) <-> ( S ` a ) = ( S ` b ) ) ) | 
						
							| 67 |  | fveq1 |  |-  ( d = b -> ( d ` 0 ) = ( b ` 0 ) ) | 
						
							| 68 | 67 | eqeq2d |  |-  ( d = b -> ( ( a ` 0 ) = ( d ` 0 ) <-> ( a ` 0 ) = ( b ` 0 ) ) ) | 
						
							| 69 | 66 68 | imbi12d |  |-  ( d = b -> ( ( ( S ` a ) = ( S ` d ) -> ( a ` 0 ) = ( d ` 0 ) ) <-> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 70 | 69 | imbi2d |  |-  ( d = b -> ( ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` d ) -> ( a ` 0 ) = ( d ` 0 ) ) ) <-> ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 71 | 64 70 | cbvral2vw |  |-  ( A. c e. dom S A. d e. dom S ( ( # ` ( S ` c ) ) = i -> ( ( S ` c ) = ( S ` d ) -> ( c ` 0 ) = ( d ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 72 | 57 71 | sylib |  |-  ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) -> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 73 | 72 | ancli |  |-  ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 74 | 35 | adantr |  |-  ( ( a e. dom S /\ b e. dom S ) -> ( # ` ( S ` a ) ) e. NN0 ) | 
						
							| 75 |  | nn0leltp1 |  |-  ( ( ( # ` ( S ` a ) ) e. NN0 /\ i e. NN0 ) -> ( ( # ` ( S ` a ) ) <_ i <-> ( # ` ( S ` a ) ) < ( i + 1 ) ) ) | 
						
							| 76 |  | nn0re |  |-  ( ( # ` ( S ` a ) ) e. NN0 -> ( # ` ( S ` a ) ) e. RR ) | 
						
							| 77 |  | nn0re |  |-  ( i e. NN0 -> i e. RR ) | 
						
							| 78 |  | leloe |  |-  ( ( ( # ` ( S ` a ) ) e. RR /\ i e. RR ) -> ( ( # ` ( S ` a ) ) <_ i <-> ( ( # ` ( S ` a ) ) < i \/ ( # ` ( S ` a ) ) = i ) ) ) | 
						
							| 79 | 76 77 78 | syl2an |  |-  ( ( ( # ` ( S ` a ) ) e. NN0 /\ i e. NN0 ) -> ( ( # ` ( S ` a ) ) <_ i <-> ( ( # ` ( S ` a ) ) < i \/ ( # ` ( S ` a ) ) = i ) ) ) | 
						
							| 80 | 75 79 | bitr3d |  |-  ( ( ( # ` ( S ` a ) ) e. NN0 /\ i e. NN0 ) -> ( ( # ` ( S ` a ) ) < ( i + 1 ) <-> ( ( # ` ( S ` a ) ) < i \/ ( # ` ( S ` a ) ) = i ) ) ) | 
						
							| 81 | 80 | ancoms |  |-  ( ( i e. NN0 /\ ( # ` ( S ` a ) ) e. NN0 ) -> ( ( # ` ( S ` a ) ) < ( i + 1 ) <-> ( ( # ` ( S ` a ) ) < i \/ ( # ` ( S ` a ) ) = i ) ) ) | 
						
							| 82 | 74 81 | sylan2 |  |-  ( ( i e. NN0 /\ ( a e. dom S /\ b e. dom S ) ) -> ( ( # ` ( S ` a ) ) < ( i + 1 ) <-> ( ( # ` ( S ` a ) ) < i \/ ( # ` ( S ` a ) ) = i ) ) ) | 
						
							| 83 | 82 | imbi1d |  |-  ( ( i e. NN0 /\ ( a e. dom S /\ b e. dom S ) ) -> ( ( ( # ` ( S ` a ) ) < ( i + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( ( # ` ( S ` a ) ) < i \/ ( # ` ( S ` a ) ) = i ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 84 |  | jaob |  |-  ( ( ( ( # ` ( S ` a ) ) < i \/ ( # ` ( S ` a ) ) = i ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 85 | 83 84 | bitrdi |  |-  ( ( i e. NN0 /\ ( a e. dom S /\ b e. dom S ) ) -> ( ( ( # ` ( S ` a ) ) < ( i + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) ) | 
						
							| 86 | 85 | 2ralbidva |  |-  ( i e. NN0 -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( i + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) ) | 
						
							| 87 |  | r19.26-2 |  |-  ( A. a e. dom S A. b e. dom S ( ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) <-> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 88 | 86 87 | bitrdi |  |-  ( i e. NN0 -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( i + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) /\ A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) = i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) ) | 
						
							| 89 | 73 88 | imbitrrid |  |-  ( i e. NN0 -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < i -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) -> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( i + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 90 | 22 25 28 31 40 89 | nn0ind |  |-  ( ( ( # ` ( S ` A ) ) + 1 ) e. NN0 -> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 91 | 19 90 | syl |  |-  ( ( A e. dom S /\ B e. dom S ) -> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 92 | 17 | nn0red |  |-  ( ( A e. dom S /\ B e. dom S ) -> ( # ` ( S ` A ) ) e. RR ) | 
						
							| 93 | 92 | ltp1d |  |-  ( ( A e. dom S /\ B e. dom S ) -> ( # ` ( S ` A ) ) < ( ( # ` ( S ` A ) ) + 1 ) ) | 
						
							| 94 |  | 2fveq3 |  |-  ( a = A -> ( # ` ( S ` a ) ) = ( # ` ( S ` A ) ) ) | 
						
							| 95 | 94 | breq1d |  |-  ( a = A -> ( ( # ` ( S ` a ) ) < ( ( # ` ( S ` A ) ) + 1 ) <-> ( # ` ( S ` A ) ) < ( ( # ` ( S ` A ) ) + 1 ) ) ) | 
						
							| 96 |  | fveqeq2 |  |-  ( a = A -> ( ( S ` a ) = ( S ` b ) <-> ( S ` A ) = ( S ` b ) ) ) | 
						
							| 97 |  | fveq1 |  |-  ( a = A -> ( a ` 0 ) = ( A ` 0 ) ) | 
						
							| 98 | 97 | eqeq1d |  |-  ( a = A -> ( ( a ` 0 ) = ( b ` 0 ) <-> ( A ` 0 ) = ( b ` 0 ) ) ) | 
						
							| 99 | 96 98 | imbi12d |  |-  ( a = A -> ( ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) <-> ( ( S ` A ) = ( S ` b ) -> ( A ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 100 | 95 99 | imbi12d |  |-  ( a = A -> ( ( ( # ` ( S ` a ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( # ` ( S ` A ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` A ) = ( S ` b ) -> ( A ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 101 |  | fveq2 |  |-  ( b = B -> ( S ` b ) = ( S ` B ) ) | 
						
							| 102 | 101 | eqeq2d |  |-  ( b = B -> ( ( S ` A ) = ( S ` b ) <-> ( S ` A ) = ( S ` B ) ) ) | 
						
							| 103 |  | fveq1 |  |-  ( b = B -> ( b ` 0 ) = ( B ` 0 ) ) | 
						
							| 104 | 103 | eqeq2d |  |-  ( b = B -> ( ( A ` 0 ) = ( b ` 0 ) <-> ( A ` 0 ) = ( B ` 0 ) ) ) | 
						
							| 105 | 102 104 | imbi12d |  |-  ( b = B -> ( ( ( S ` A ) = ( S ` b ) -> ( A ` 0 ) = ( b ` 0 ) ) <-> ( ( S ` A ) = ( S ` B ) -> ( A ` 0 ) = ( B ` 0 ) ) ) ) | 
						
							| 106 | 105 | imbi2d |  |-  ( b = B -> ( ( ( # ` ( S ` A ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` A ) = ( S ` b ) -> ( A ` 0 ) = ( b ` 0 ) ) ) <-> ( ( # ` ( S ` A ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` A ) = ( S ` B ) -> ( A ` 0 ) = ( B ` 0 ) ) ) ) ) | 
						
							| 107 | 100 106 | rspc2v |  |-  ( ( A e. dom S /\ B e. dom S ) -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) -> ( ( # ` ( S ` A ) ) < ( ( # ` ( S ` A ) ) + 1 ) -> ( ( S ` A ) = ( S ` B ) -> ( A ` 0 ) = ( B ` 0 ) ) ) ) ) | 
						
							| 108 | 91 93 107 | mp2d |  |-  ( ( A e. dom S /\ B e. dom S ) -> ( ( S ` A ) = ( S ` B ) -> ( A ` 0 ) = ( B ` 0 ) ) ) | 
						
							| 109 | 108 | 3impia |  |-  ( ( A e. dom S /\ B e. dom S /\ ( S ` A ) = ( S ` B ) ) -> ( A ` 0 ) = ( B ` 0 ) ) |