| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lgsdir2lem2.1 |  |-  ( K e. ZZ /\ 2 || ( K + 1 ) /\ ( ( A e. ZZ /\ -. 2 || A ) -> ( ( A mod 8 ) e. ( 0 ... K ) -> ( A mod 8 ) e. S ) ) ) | 
						
							| 2 |  | lgsdir2lem2.2 |  |-  M = ( K + 1 ) | 
						
							| 3 |  | lgsdir2lem2.3 |  |-  N = ( M + 1 ) | 
						
							| 4 |  | lgsdir2lem2.4 |  |-  N e. S | 
						
							| 5 | 1 | simp1i |  |-  K e. ZZ | 
						
							| 6 |  | peano2z |  |-  ( K e. ZZ -> ( K + 1 ) e. ZZ ) | 
						
							| 7 | 5 6 | ax-mp |  |-  ( K + 1 ) e. ZZ | 
						
							| 8 | 2 7 | eqeltri |  |-  M e. ZZ | 
						
							| 9 |  | peano2z |  |-  ( M e. ZZ -> ( M + 1 ) e. ZZ ) | 
						
							| 10 | 8 9 | ax-mp |  |-  ( M + 1 ) e. ZZ | 
						
							| 11 | 3 10 | eqeltri |  |-  N e. ZZ | 
						
							| 12 | 1 | simp2i |  |-  2 || ( K + 1 ) | 
						
							| 13 |  | 2z |  |-  2 e. ZZ | 
						
							| 14 |  | dvdsadd |  |-  ( ( 2 e. ZZ /\ ( K + 1 ) e. ZZ ) -> ( 2 || ( K + 1 ) <-> 2 || ( 2 + ( K + 1 ) ) ) ) | 
						
							| 15 | 13 7 14 | mp2an |  |-  ( 2 || ( K + 1 ) <-> 2 || ( 2 + ( K + 1 ) ) ) | 
						
							| 16 | 12 15 | mpbi |  |-  2 || ( 2 + ( K + 1 ) ) | 
						
							| 17 |  | zcn |  |-  ( K e. ZZ -> K e. CC ) | 
						
							| 18 | 5 17 | ax-mp |  |-  K e. CC | 
						
							| 19 |  | ax-1cn |  |-  1 e. CC | 
						
							| 20 | 18 19 | addcomi |  |-  ( K + 1 ) = ( 1 + K ) | 
						
							| 21 | 2 20 | eqtri |  |-  M = ( 1 + K ) | 
						
							| 22 | 21 | oveq1i |  |-  ( M + 1 ) = ( ( 1 + K ) + 1 ) | 
						
							| 23 | 3 22 | eqtri |  |-  N = ( ( 1 + K ) + 1 ) | 
						
							| 24 |  | df-2 |  |-  2 = ( 1 + 1 ) | 
						
							| 25 | 24 | oveq1i |  |-  ( 2 + K ) = ( ( 1 + 1 ) + K ) | 
						
							| 26 | 19 18 19 | add32i |  |-  ( ( 1 + K ) + 1 ) = ( ( 1 + 1 ) + K ) | 
						
							| 27 | 25 26 | eqtr4i |  |-  ( 2 + K ) = ( ( 1 + K ) + 1 ) | 
						
							| 28 | 23 27 | eqtr4i |  |-  N = ( 2 + K ) | 
						
							| 29 | 28 | oveq1i |  |-  ( N + 1 ) = ( ( 2 + K ) + 1 ) | 
						
							| 30 |  | 2cn |  |-  2 e. CC | 
						
							| 31 | 30 18 19 | addassi |  |-  ( ( 2 + K ) + 1 ) = ( 2 + ( K + 1 ) ) | 
						
							| 32 | 29 31 | eqtri |  |-  ( N + 1 ) = ( 2 + ( K + 1 ) ) | 
						
							| 33 | 16 32 | breqtrri |  |-  2 || ( N + 1 ) | 
						
							| 34 |  | elfzuz2 |  |-  ( ( A mod 8 ) e. ( 0 ... N ) -> N e. ( ZZ>= ` 0 ) ) | 
						
							| 35 |  | fzm1 |  |-  ( N e. ( ZZ>= ` 0 ) -> ( ( A mod 8 ) e. ( 0 ... N ) <-> ( ( A mod 8 ) e. ( 0 ... ( N - 1 ) ) \/ ( A mod 8 ) = N ) ) ) | 
						
							| 36 | 34 35 | syl |  |-  ( ( A mod 8 ) e. ( 0 ... N ) -> ( ( A mod 8 ) e. ( 0 ... N ) <-> ( ( A mod 8 ) e. ( 0 ... ( N - 1 ) ) \/ ( A mod 8 ) = N ) ) ) | 
						
							| 37 | 36 | ibi |  |-  ( ( A mod 8 ) e. ( 0 ... N ) -> ( ( A mod 8 ) e. ( 0 ... ( N - 1 ) ) \/ ( A mod 8 ) = N ) ) | 
						
							| 38 |  | elfzuz2 |  |-  ( ( A mod 8 ) e. ( 0 ... M ) -> M e. ( ZZ>= ` 0 ) ) | 
						
							| 39 |  | fzm1 |  |-  ( M e. ( ZZ>= ` 0 ) -> ( ( A mod 8 ) e. ( 0 ... M ) <-> ( ( A mod 8 ) e. ( 0 ... ( M - 1 ) ) \/ ( A mod 8 ) = M ) ) ) | 
						
							| 40 | 38 39 | syl |  |-  ( ( A mod 8 ) e. ( 0 ... M ) -> ( ( A mod 8 ) e. ( 0 ... M ) <-> ( ( A mod 8 ) e. ( 0 ... ( M - 1 ) ) \/ ( A mod 8 ) = M ) ) ) | 
						
							| 41 | 40 | ibi |  |-  ( ( A mod 8 ) e. ( 0 ... M ) -> ( ( A mod 8 ) e. ( 0 ... ( M - 1 ) ) \/ ( A mod 8 ) = M ) ) | 
						
							| 42 |  | zcn |  |-  ( M e. ZZ -> M e. CC ) | 
						
							| 43 | 8 42 | ax-mp |  |-  M e. CC | 
						
							| 44 | 43 19 3 | mvrraddi |  |-  ( N - 1 ) = M | 
						
							| 45 | 44 | oveq2i |  |-  ( 0 ... ( N - 1 ) ) = ( 0 ... M ) | 
						
							| 46 | 41 45 | eleq2s |  |-  ( ( A mod 8 ) e. ( 0 ... ( N - 1 ) ) -> ( ( A mod 8 ) e. ( 0 ... ( M - 1 ) ) \/ ( A mod 8 ) = M ) ) | 
						
							| 47 | 18 19 2 | mvrraddi |  |-  ( M - 1 ) = K | 
						
							| 48 | 47 | oveq2i |  |-  ( 0 ... ( M - 1 ) ) = ( 0 ... K ) | 
						
							| 49 | 48 | eleq2i |  |-  ( ( A mod 8 ) e. ( 0 ... ( M - 1 ) ) <-> ( A mod 8 ) e. ( 0 ... K ) ) | 
						
							| 50 | 1 | simp3i |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> ( ( A mod 8 ) e. ( 0 ... K ) -> ( A mod 8 ) e. S ) ) | 
						
							| 51 | 49 50 | biimtrid |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> ( ( A mod 8 ) e. ( 0 ... ( M - 1 ) ) -> ( A mod 8 ) e. S ) ) | 
						
							| 52 |  | 2nn |  |-  2 e. NN | 
						
							| 53 |  | 8nn |  |-  8 e. NN | 
						
							| 54 |  | 4z |  |-  4 e. ZZ | 
						
							| 55 |  | dvdsmul2 |  |-  ( ( 4 e. ZZ /\ 2 e. ZZ ) -> 2 || ( 4 x. 2 ) ) | 
						
							| 56 | 54 13 55 | mp2an |  |-  2 || ( 4 x. 2 ) | 
						
							| 57 |  | 4t2e8 |  |-  ( 4 x. 2 ) = 8 | 
						
							| 58 | 56 57 | breqtri |  |-  2 || 8 | 
						
							| 59 |  | dvdsmod |  |-  ( ( ( 2 e. NN /\ 8 e. NN /\ A e. ZZ ) /\ 2 || 8 ) -> ( 2 || ( A mod 8 ) <-> 2 || A ) ) | 
						
							| 60 | 58 59 | mpan2 |  |-  ( ( 2 e. NN /\ 8 e. NN /\ A e. ZZ ) -> ( 2 || ( A mod 8 ) <-> 2 || A ) ) | 
						
							| 61 | 52 53 60 | mp3an12 |  |-  ( A e. ZZ -> ( 2 || ( A mod 8 ) <-> 2 || A ) ) | 
						
							| 62 | 61 | notbid |  |-  ( A e. ZZ -> ( -. 2 || ( A mod 8 ) <-> -. 2 || A ) ) | 
						
							| 63 | 62 | biimpar |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> -. 2 || ( A mod 8 ) ) | 
						
							| 64 | 12 2 | breqtrri |  |-  2 || M | 
						
							| 65 |  | id |  |-  ( ( A mod 8 ) = M -> ( A mod 8 ) = M ) | 
						
							| 66 | 64 65 | breqtrrid |  |-  ( ( A mod 8 ) = M -> 2 || ( A mod 8 ) ) | 
						
							| 67 | 63 66 | nsyl |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> -. ( A mod 8 ) = M ) | 
						
							| 68 | 67 | pm2.21d |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> ( ( A mod 8 ) = M -> ( A mod 8 ) e. S ) ) | 
						
							| 69 | 51 68 | jaod |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> ( ( ( A mod 8 ) e. ( 0 ... ( M - 1 ) ) \/ ( A mod 8 ) = M ) -> ( A mod 8 ) e. S ) ) | 
						
							| 70 | 46 69 | syl5 |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> ( ( A mod 8 ) e. ( 0 ... ( N - 1 ) ) -> ( A mod 8 ) e. S ) ) | 
						
							| 71 |  | eleq1 |  |-  ( ( A mod 8 ) = N -> ( ( A mod 8 ) e. S <-> N e. S ) ) | 
						
							| 72 | 4 71 | mpbiri |  |-  ( ( A mod 8 ) = N -> ( A mod 8 ) e. S ) | 
						
							| 73 | 72 | a1i |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> ( ( A mod 8 ) = N -> ( A mod 8 ) e. S ) ) | 
						
							| 74 | 70 73 | jaod |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> ( ( ( A mod 8 ) e. ( 0 ... ( N - 1 ) ) \/ ( A mod 8 ) = N ) -> ( A mod 8 ) e. S ) ) | 
						
							| 75 | 37 74 | syl5 |  |-  ( ( A e. ZZ /\ -. 2 || A ) -> ( ( A mod 8 ) e. ( 0 ... N ) -> ( A mod 8 ) e. S ) ) | 
						
							| 76 | 11 33 75 | 3pm3.2i |  |-  ( N e. ZZ /\ 2 || ( N + 1 ) /\ ( ( A e. ZZ /\ -. 2 || A ) -> ( ( A mod 8 ) e. ( 0 ... N ) -> ( A mod 8 ) e. S ) ) ) |