| Step | Hyp | Ref | Expression | 
						
							| 1 |  | axlowdimlem15.1 |  |-  F = ( i e. ( 1 ... ( N - 1 ) ) |-> if ( i = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) ) ) | 
						
							| 2 |  | eqid |  |-  ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) = ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) | 
						
							| 3 | 2 | axlowdimlem7 |  |-  ( N e. ( ZZ>= ` 3 ) -> ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) e. ( EE ` N ) ) | 
						
							| 4 | 3 | adantr |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ i e. ( 1 ... ( N - 1 ) ) ) -> ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) e. ( EE ` N ) ) | 
						
							| 5 |  | eluzge3nn |  |-  ( N e. ( ZZ>= ` 3 ) -> N e. NN ) | 
						
							| 6 |  | eqid |  |-  ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) = ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) | 
						
							| 7 | 6 | axlowdimlem10 |  |-  ( ( N e. NN /\ i e. ( 1 ... ( N - 1 ) ) ) -> ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) e. ( EE ` N ) ) | 
						
							| 8 | 5 7 | sylan |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ i e. ( 1 ... ( N - 1 ) ) ) -> ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) e. ( EE ` N ) ) | 
						
							| 9 | 4 8 | ifcld |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ i e. ( 1 ... ( N - 1 ) ) ) -> if ( i = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) ) e. ( EE ` N ) ) | 
						
							| 10 | 9 1 | fmptd |  |-  ( N e. ( ZZ>= ` 3 ) -> F : ( 1 ... ( N - 1 ) ) --> ( EE ` N ) ) | 
						
							| 11 |  | eqeq1 |  |-  ( i = j -> ( i = 1 <-> j = 1 ) ) | 
						
							| 12 |  | oveq1 |  |-  ( i = j -> ( i + 1 ) = ( j + 1 ) ) | 
						
							| 13 | 12 | opeq1d |  |-  ( i = j -> <. ( i + 1 ) , 1 >. = <. ( j + 1 ) , 1 >. ) | 
						
							| 14 | 13 | sneqd |  |-  ( i = j -> { <. ( i + 1 ) , 1 >. } = { <. ( j + 1 ) , 1 >. } ) | 
						
							| 15 | 12 | sneqd |  |-  ( i = j -> { ( i + 1 ) } = { ( j + 1 ) } ) | 
						
							| 16 | 15 | difeq2d |  |-  ( i = j -> ( ( 1 ... N ) \ { ( i + 1 ) } ) = ( ( 1 ... N ) \ { ( j + 1 ) } ) ) | 
						
							| 17 | 16 | xpeq1d |  |-  ( i = j -> ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) = ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) | 
						
							| 18 | 14 17 | uneq12d |  |-  ( i = j -> ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) = ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) | 
						
							| 19 | 11 18 | ifbieq2d |  |-  ( i = j -> if ( i = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) ) = if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) ) | 
						
							| 20 |  | snex |  |-  { <. 3 , -u 1 >. } e. _V | 
						
							| 21 |  | ovex |  |-  ( 1 ... N ) e. _V | 
						
							| 22 | 21 | difexi |  |-  ( ( 1 ... N ) \ { 3 } ) e. _V | 
						
							| 23 |  | snex |  |-  { 0 } e. _V | 
						
							| 24 | 22 23 | xpex |  |-  ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) e. _V | 
						
							| 25 | 20 24 | unex |  |-  ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) e. _V | 
						
							| 26 |  | snex |  |-  { <. ( j + 1 ) , 1 >. } e. _V | 
						
							| 27 | 21 | difexi |  |-  ( ( 1 ... N ) \ { ( j + 1 ) } ) e. _V | 
						
							| 28 | 27 23 | xpex |  |-  ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) e. _V | 
						
							| 29 | 26 28 | unex |  |-  ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) e. _V | 
						
							| 30 | 25 29 | ifex |  |-  if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) e. _V | 
						
							| 31 | 19 1 30 | fvmpt |  |-  ( j e. ( 1 ... ( N - 1 ) ) -> ( F ` j ) = if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) ) | 
						
							| 32 |  | eqeq1 |  |-  ( i = k -> ( i = 1 <-> k = 1 ) ) | 
						
							| 33 |  | oveq1 |  |-  ( i = k -> ( i + 1 ) = ( k + 1 ) ) | 
						
							| 34 | 33 | opeq1d |  |-  ( i = k -> <. ( i + 1 ) , 1 >. = <. ( k + 1 ) , 1 >. ) | 
						
							| 35 | 34 | sneqd |  |-  ( i = k -> { <. ( i + 1 ) , 1 >. } = { <. ( k + 1 ) , 1 >. } ) | 
						
							| 36 | 33 | sneqd |  |-  ( i = k -> { ( i + 1 ) } = { ( k + 1 ) } ) | 
						
							| 37 | 36 | difeq2d |  |-  ( i = k -> ( ( 1 ... N ) \ { ( i + 1 ) } ) = ( ( 1 ... N ) \ { ( k + 1 ) } ) ) | 
						
							| 38 | 37 | xpeq1d |  |-  ( i = k -> ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) = ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) | 
						
							| 39 | 35 38 | uneq12d |  |-  ( i = k -> ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) | 
						
							| 40 | 32 39 | ifbieq2d |  |-  ( i = k -> if ( i = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( i + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( i + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) ) | 
						
							| 41 |  | snex |  |-  { <. ( k + 1 ) , 1 >. } e. _V | 
						
							| 42 | 21 | difexi |  |-  ( ( 1 ... N ) \ { ( k + 1 ) } ) e. _V | 
						
							| 43 | 42 23 | xpex |  |-  ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) e. _V | 
						
							| 44 | 41 43 | unex |  |-  ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) e. _V | 
						
							| 45 | 25 44 | ifex |  |-  if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) e. _V | 
						
							| 46 | 40 1 45 | fvmpt |  |-  ( k e. ( 1 ... ( N - 1 ) ) -> ( F ` k ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) ) | 
						
							| 47 | 31 46 | eqeqan12d |  |-  ( ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) -> ( ( F ` j ) = ( F ` k ) <-> if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) ) ) | 
						
							| 48 | 47 | adantl |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( ( F ` j ) = ( F ` k ) <-> if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) ) ) | 
						
							| 49 |  | eqtr3 |  |-  ( ( j = 1 /\ k = 1 ) -> j = k ) | 
						
							| 50 | 49 | 2a1d |  |-  ( ( j = 1 /\ k = 1 ) -> ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) -> j = k ) ) ) | 
						
							| 51 |  | eqid |  |-  ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) | 
						
							| 52 | 2 51 | axlowdimlem13 |  |-  ( ( N e. NN /\ k e. ( 1 ... ( N - 1 ) ) ) -> ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) =/= ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) | 
						
							| 53 | 52 | neneqd |  |-  ( ( N e. NN /\ k e. ( 1 ... ( N - 1 ) ) ) -> -. ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) | 
						
							| 54 | 53 | pm2.21d |  |-  ( ( N e. NN /\ k e. ( 1 ... ( N - 1 ) ) ) -> ( ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) -> j = k ) ) | 
						
							| 55 | 54 | adantrl |  |-  ( ( N e. NN /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) -> j = k ) ) | 
						
							| 56 | 5 55 | sylan |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) -> j = k ) ) | 
						
							| 57 |  | iftrue |  |-  ( j = 1 -> if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) ) | 
						
							| 58 |  | iffalse |  |-  ( -. k = 1 -> if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) | 
						
							| 59 | 57 58 | eqeqan12d |  |-  ( ( j = 1 /\ -. k = 1 ) -> ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) <-> ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) ) | 
						
							| 60 | 59 | imbi1d |  |-  ( ( j = 1 /\ -. k = 1 ) -> ( ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) -> j = k ) <-> ( ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) -> j = k ) ) ) | 
						
							| 61 | 56 60 | imbitrrid |  |-  ( ( j = 1 /\ -. k = 1 ) -> ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) -> j = k ) ) ) | 
						
							| 62 |  | eqid |  |-  ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) | 
						
							| 63 | 2 62 | axlowdimlem13 |  |-  ( ( N e. NN /\ j e. ( 1 ... ( N - 1 ) ) ) -> ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) =/= ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) | 
						
							| 64 | 63 | necomd |  |-  ( ( N e. NN /\ j e. ( 1 ... ( N - 1 ) ) ) -> ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) =/= ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) ) | 
						
							| 65 | 64 | neneqd |  |-  ( ( N e. NN /\ j e. ( 1 ... ( N - 1 ) ) ) -> -. ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) ) | 
						
							| 66 | 65 | pm2.21d |  |-  ( ( N e. NN /\ j e. ( 1 ... ( N - 1 ) ) ) -> ( ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) -> j = k ) ) | 
						
							| 67 | 5 66 | sylan |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ j e. ( 1 ... ( N - 1 ) ) ) -> ( ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) -> j = k ) ) | 
						
							| 68 | 67 | adantrr |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) -> j = k ) ) | 
						
							| 69 |  | iffalse |  |-  ( -. j = 1 -> if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) | 
						
							| 70 |  | iftrue |  |-  ( k = 1 -> if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) = ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) ) | 
						
							| 71 | 69 70 | eqeqan12d |  |-  ( ( -. j = 1 /\ k = 1 ) -> ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) <-> ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) ) ) | 
						
							| 72 | 71 | imbi1d |  |-  ( ( -. j = 1 /\ k = 1 ) -> ( ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) -> j = k ) <-> ( ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) -> j = k ) ) ) | 
						
							| 73 | 68 72 | imbitrrid |  |-  ( ( -. j = 1 /\ k = 1 ) -> ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) -> j = k ) ) ) | 
						
							| 74 | 62 51 | axlowdimlem14 |  |-  ( ( N e. NN /\ j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) -> ( ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) -> j = k ) ) | 
						
							| 75 | 74 | 3expb |  |-  ( ( N e. NN /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) -> j = k ) ) | 
						
							| 76 | 5 75 | sylan |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) -> j = k ) ) | 
						
							| 77 | 69 58 | eqeqan12d |  |-  ( ( -. j = 1 /\ -. k = 1 ) -> ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) <-> ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) ) | 
						
							| 78 | 77 | imbi1d |  |-  ( ( -. j = 1 /\ -. k = 1 ) -> ( ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) -> j = k ) <-> ( ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) = ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) -> j = k ) ) ) | 
						
							| 79 | 76 78 | imbitrrid |  |-  ( ( -. j = 1 /\ -. k = 1 ) -> ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) -> j = k ) ) ) | 
						
							| 80 | 50 61 73 79 | 4cases |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( if ( j = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( j + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( j + 1 ) } ) X. { 0 } ) ) ) = if ( k = 1 , ( { <. 3 , -u 1 >. } u. ( ( ( 1 ... N ) \ { 3 } ) X. { 0 } ) ) , ( { <. ( k + 1 ) , 1 >. } u. ( ( ( 1 ... N ) \ { ( k + 1 ) } ) X. { 0 } ) ) ) -> j = k ) ) | 
						
							| 81 | 48 80 | sylbid |  |-  ( ( N e. ( ZZ>= ` 3 ) /\ ( j e. ( 1 ... ( N - 1 ) ) /\ k e. ( 1 ... ( N - 1 ) ) ) ) -> ( ( F ` j ) = ( F ` k ) -> j = k ) ) | 
						
							| 82 | 81 | ralrimivva |  |-  ( N e. ( ZZ>= ` 3 ) -> A. j e. ( 1 ... ( N - 1 ) ) A. k e. ( 1 ... ( N - 1 ) ) ( ( F ` j ) = ( F ` k ) -> j = k ) ) | 
						
							| 83 |  | dff13 |  |-  ( F : ( 1 ... ( N - 1 ) ) -1-1-> ( EE ` N ) <-> ( F : ( 1 ... ( N - 1 ) ) --> ( EE ` N ) /\ A. j e. ( 1 ... ( N - 1 ) ) A. k e. ( 1 ... ( N - 1 ) ) ( ( F ` j ) = ( F ` k ) -> j = k ) ) ) | 
						
							| 84 | 10 82 83 | sylanbrc |  |-  ( N e. ( ZZ>= ` 3 ) -> F : ( 1 ... ( N - 1 ) ) -1-1-> ( EE ` N ) ) |