| 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 |  | efgredlem.1 |  |-  ( ph -> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( # ` ( S ` A ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 8 |  | efgredlem.2 |  |-  ( ph -> A e. dom S ) | 
						
							| 9 |  | efgredlem.3 |  |-  ( ph -> B e. dom S ) | 
						
							| 10 |  | efgredlem.4 |  |-  ( ph -> ( S ` A ) = ( S ` B ) ) | 
						
							| 11 |  | efgredlem.5 |  |-  ( ph -> -. ( A ` 0 ) = ( B ` 0 ) ) | 
						
							| 12 |  | efgredlemb.k |  |-  K = ( ( ( # ` A ) - 1 ) - 1 ) | 
						
							| 13 |  | efgredlemb.l |  |-  L = ( ( ( # ` B ) - 1 ) - 1 ) | 
						
							| 14 |  | efgredlemb.p |  |-  ( ph -> P e. ( 0 ... ( # ` ( A ` K ) ) ) ) | 
						
							| 15 |  | efgredlemb.q |  |-  ( ph -> Q e. ( 0 ... ( # ` ( B ` L ) ) ) ) | 
						
							| 16 |  | efgredlemb.u |  |-  ( ph -> U e. ( I X. 2o ) ) | 
						
							| 17 |  | efgredlemb.v |  |-  ( ph -> V e. ( I X. 2o ) ) | 
						
							| 18 |  | efgredlemb.6 |  |-  ( ph -> ( S ` A ) = ( P ( T ` ( A ` K ) ) U ) ) | 
						
							| 19 |  | efgredlemb.7 |  |-  ( ph -> ( S ` B ) = ( Q ( T ` ( B ` L ) ) V ) ) | 
						
							| 20 |  | efgredlemb.8 |  |-  ( ph -> -. ( A ` K ) = ( B ` L ) ) | 
						
							| 21 |  | fveq2 |  |-  ( ( S ` A ) = ( S ` B ) -> ( # ` ( S ` A ) ) = ( # ` ( S ` B ) ) ) | 
						
							| 22 | 21 | breq2d |  |-  ( ( S ` A ) = ( S ` B ) -> ( ( # ` ( S ` a ) ) < ( # ` ( S ` A ) ) <-> ( # ` ( S ` a ) ) < ( # ` ( S ` B ) ) ) ) | 
						
							| 23 | 22 | imbi1d |  |-  ( ( S ` A ) = ( S ` B ) -> ( ( ( # ` ( S ` a ) ) < ( # ` ( S ` A ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> ( ( # ` ( S ` a ) ) < ( # ` ( S ` B ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 24 | 23 | 2ralbidv |  |-  ( ( S ` A ) = ( S ` B ) -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( # ` ( S ` A ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( # ` ( S ` B ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 25 | 10 24 | syl |  |-  ( ph -> ( A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( # ` ( S ` A ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) <-> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( # ` ( S ` B ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) ) | 
						
							| 26 | 7 25 | mpbid |  |-  ( ph -> A. a e. dom S A. b e. dom S ( ( # ` ( S ` a ) ) < ( # ` ( S ` B ) ) -> ( ( S ` a ) = ( S ` b ) -> ( a ` 0 ) = ( b ` 0 ) ) ) ) | 
						
							| 27 | 10 | eqcomd |  |-  ( ph -> ( S ` B ) = ( S ` A ) ) | 
						
							| 28 |  | eqcom |  |-  ( ( A ` 0 ) = ( B ` 0 ) <-> ( B ` 0 ) = ( A ` 0 ) ) | 
						
							| 29 | 11 28 | sylnib |  |-  ( ph -> -. ( B ` 0 ) = ( A ` 0 ) ) | 
						
							| 30 |  | eqcom |  |-  ( ( A ` K ) = ( B ` L ) <-> ( B ` L ) = ( A ` K ) ) | 
						
							| 31 | 20 30 | sylnib |  |-  ( ph -> -. ( B ` L ) = ( A ` K ) ) | 
						
							| 32 | 1 2 3 4 5 6 26 9 8 27 29 13 12 15 14 17 16 19 18 31 | efgredlemc |  |-  ( ph -> ( Q e. ( ZZ>= ` P ) -> ( B ` 0 ) = ( A ` 0 ) ) ) | 
						
							| 33 | 32 28 | imbitrrdi |  |-  ( ph -> ( Q e. ( ZZ>= ` P ) -> ( A ` 0 ) = ( B ` 0 ) ) ) | 
						
							| 34 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | efgredlemc |  |-  ( ph -> ( P e. ( ZZ>= ` Q ) -> ( A ` 0 ) = ( B ` 0 ) ) ) | 
						
							| 35 | 14 | elfzelzd |  |-  ( ph -> P e. ZZ ) | 
						
							| 36 | 15 | elfzelzd |  |-  ( ph -> Q e. ZZ ) | 
						
							| 37 |  | uztric |  |-  ( ( P e. ZZ /\ Q e. ZZ ) -> ( Q e. ( ZZ>= ` P ) \/ P e. ( ZZ>= ` Q ) ) ) | 
						
							| 38 | 35 36 37 | syl2anc |  |-  ( ph -> ( Q e. ( ZZ>= ` P ) \/ P e. ( ZZ>= ` Q ) ) ) | 
						
							| 39 | 33 34 38 | mpjaod |  |-  ( ph -> ( A ` 0 ) = ( B ` 0 ) ) | 
						
							| 40 | 39 11 | pm2.65i |  |-  -. ph |