| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lgsdir2lem2.1 | ⊢ ( 𝐾  ∈  ℤ  ∧  2  ∥  ( 𝐾  +  1 )  ∧  ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝐾 )  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) ) | 
						
							| 2 |  | lgsdir2lem2.2 | ⊢ 𝑀  =  ( 𝐾  +  1 ) | 
						
							| 3 |  | lgsdir2lem2.3 | ⊢ 𝑁  =  ( 𝑀  +  1 ) | 
						
							| 4 |  | lgsdir2lem2.4 | ⊢ 𝑁  ∈  𝑆 | 
						
							| 5 | 1 | simp1i | ⊢ 𝐾  ∈  ℤ | 
						
							| 6 |  | peano2z | ⊢ ( 𝐾  ∈  ℤ  →  ( 𝐾  +  1 )  ∈  ℤ ) | 
						
							| 7 | 5 6 | ax-mp | ⊢ ( 𝐾  +  1 )  ∈  ℤ | 
						
							| 8 | 2 7 | eqeltri | ⊢ 𝑀  ∈  ℤ | 
						
							| 9 |  | peano2z | ⊢ ( 𝑀  ∈  ℤ  →  ( 𝑀  +  1 )  ∈  ℤ ) | 
						
							| 10 | 8 9 | ax-mp | ⊢ ( 𝑀  +  1 )  ∈  ℤ | 
						
							| 11 | 3 10 | eqeltri | ⊢ 𝑁  ∈  ℤ | 
						
							| 12 | 1 | simp2i | ⊢ 2  ∥  ( 𝐾  +  1 ) | 
						
							| 13 |  | 2z | ⊢ 2  ∈  ℤ | 
						
							| 14 |  | dvdsadd | ⊢ ( ( 2  ∈  ℤ  ∧  ( 𝐾  +  1 )  ∈  ℤ )  →  ( 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  ∈  ℤ  →  𝐾  ∈  ℂ ) | 
						
							| 18 | 5 17 | ax-mp | ⊢ 𝐾  ∈  ℂ | 
						
							| 19 |  | ax-1cn | ⊢ 1  ∈  ℂ | 
						
							| 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  ∈  ℂ | 
						
							| 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 )  ∈  ( 0 ... 𝑁 )  →  𝑁  ∈  ( ℤ≥ ‘ 0 ) ) | 
						
							| 35 |  | fzm1 | ⊢ ( 𝑁  ∈  ( ℤ≥ ‘ 0 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑁 )  ↔  ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑁  −  1 ) )  ∨  ( 𝐴  mod  8 )  =  𝑁 ) ) ) | 
						
							| 36 | 34 35 | syl | ⊢ ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑁 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑁 )  ↔  ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑁  −  1 ) )  ∨  ( 𝐴  mod  8 )  =  𝑁 ) ) ) | 
						
							| 37 | 36 | ibi | ⊢ ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑁 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑁  −  1 ) )  ∨  ( 𝐴  mod  8 )  =  𝑁 ) ) | 
						
							| 38 |  | elfzuz2 | ⊢ ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑀 )  →  𝑀  ∈  ( ℤ≥ ‘ 0 ) ) | 
						
							| 39 |  | fzm1 | ⊢ ( 𝑀  ∈  ( ℤ≥ ‘ 0 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑀 )  ↔  ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑀  −  1 ) )  ∨  ( 𝐴  mod  8 )  =  𝑀 ) ) ) | 
						
							| 40 | 38 39 | syl | ⊢ ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑀 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑀 )  ↔  ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑀  −  1 ) )  ∨  ( 𝐴  mod  8 )  =  𝑀 ) ) ) | 
						
							| 41 | 40 | ibi | ⊢ ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑀 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑀  −  1 ) )  ∨  ( 𝐴  mod  8 )  =  𝑀 ) ) | 
						
							| 42 |  | zcn | ⊢ ( 𝑀  ∈  ℤ  →  𝑀  ∈  ℂ ) | 
						
							| 43 | 8 42 | ax-mp | ⊢ 𝑀  ∈  ℂ | 
						
							| 44 | 43 19 3 | mvrraddi | ⊢ ( 𝑁  −  1 )  =  𝑀 | 
						
							| 45 | 44 | oveq2i | ⊢ ( 0 ... ( 𝑁  −  1 ) )  =  ( 0 ... 𝑀 ) | 
						
							| 46 | 41 45 | eleq2s | ⊢ ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑁  −  1 ) )  →  ( ( 𝐴  mod  8 )  ∈  ( 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 )  ∈  ( 0 ... ( 𝑀  −  1 ) )  ↔  ( 𝐴  mod  8 )  ∈  ( 0 ... 𝐾 ) ) | 
						
							| 50 | 1 | simp3i | ⊢ ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝐾 )  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) | 
						
							| 51 | 49 50 | biimtrid | ⊢ ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑀  −  1 ) )  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) | 
						
							| 52 |  | 2nn | ⊢ 2  ∈  ℕ | 
						
							| 53 |  | 8nn | ⊢ 8  ∈  ℕ | 
						
							| 54 |  | 4z | ⊢ 4  ∈  ℤ | 
						
							| 55 |  | dvdsmul2 | ⊢ ( ( 4  ∈  ℤ  ∧  2  ∈  ℤ )  →  2  ∥  ( 4  ·  2 ) ) | 
						
							| 56 | 54 13 55 | mp2an | ⊢ 2  ∥  ( 4  ·  2 ) | 
						
							| 57 |  | 4t2e8 | ⊢ ( 4  ·  2 )  =  8 | 
						
							| 58 | 56 57 | breqtri | ⊢ 2  ∥  8 | 
						
							| 59 |  | dvdsmod | ⊢ ( ( ( 2  ∈  ℕ  ∧  8  ∈  ℕ  ∧  𝐴  ∈  ℤ )  ∧  2  ∥  8 )  →  ( 2  ∥  ( 𝐴  mod  8 )  ↔  2  ∥  𝐴 ) ) | 
						
							| 60 | 58 59 | mpan2 | ⊢ ( ( 2  ∈  ℕ  ∧  8  ∈  ℕ  ∧  𝐴  ∈  ℤ )  →  ( 2  ∥  ( 𝐴  mod  8 )  ↔  2  ∥  𝐴 ) ) | 
						
							| 61 | 52 53 60 | mp3an12 | ⊢ ( 𝐴  ∈  ℤ  →  ( 2  ∥  ( 𝐴  mod  8 )  ↔  2  ∥  𝐴 ) ) | 
						
							| 62 | 61 | notbid | ⊢ ( 𝐴  ∈  ℤ  →  ( ¬  2  ∥  ( 𝐴  mod  8 )  ↔  ¬  2  ∥  𝐴 ) ) | 
						
							| 63 | 62 | biimpar | ⊢ ( ( 𝐴  ∈  ℤ  ∧  ¬  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  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ¬  ( 𝐴  mod  8 )  =  𝑀 ) | 
						
							| 68 | 67 | pm2.21d | ⊢ ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( 𝐴  mod  8 )  =  𝑀  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) | 
						
							| 69 | 51 68 | jaod | ⊢ ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑀  −  1 ) )  ∨  ( 𝐴  mod  8 )  =  𝑀 )  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) | 
						
							| 70 | 46 69 | syl5 | ⊢ ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑁  −  1 ) )  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) | 
						
							| 71 |  | eleq1 | ⊢ ( ( 𝐴  mod  8 )  =  𝑁  →  ( ( 𝐴  mod  8 )  ∈  𝑆  ↔  𝑁  ∈  𝑆 ) ) | 
						
							| 72 | 4 71 | mpbiri | ⊢ ( ( 𝐴  mod  8 )  =  𝑁  →  ( 𝐴  mod  8 )  ∈  𝑆 ) | 
						
							| 73 | 72 | a1i | ⊢ ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( 𝐴  mod  8 )  =  𝑁  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) | 
						
							| 74 | 70 73 | jaod | ⊢ ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( ( 𝐴  mod  8 )  ∈  ( 0 ... ( 𝑁  −  1 ) )  ∨  ( 𝐴  mod  8 )  =  𝑁 )  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) | 
						
							| 75 | 37 74 | syl5 | ⊢ ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑁 )  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) | 
						
							| 76 | 11 33 75 | 3pm3.2i | ⊢ ( 𝑁  ∈  ℤ  ∧  2  ∥  ( 𝑁  +  1 )  ∧  ( ( 𝐴  ∈  ℤ  ∧  ¬  2  ∥  𝐴 )  →  ( ( 𝐴  mod  8 )  ∈  ( 0 ... 𝑁 )  →  ( 𝐴  mod  8 )  ∈  𝑆 ) ) ) |