Proof of Theorem lgsdir2lem3
| Step | Hyp | Ref
 | Expression | 
| 1 |   | simpl 109 | 
. . . 4
⊢ ((𝐴 ∈ ℤ ∧ ¬ 2
∥ 𝐴) → 𝐴 ∈
ℤ) | 
| 2 |   | 8nn 9158 | 
. . . 4
⊢ 8 ∈
ℕ | 
| 3 |   | zmodfz 10438 | 
. . . 4
⊢ ((𝐴 ∈ ℤ ∧ 8 ∈
ℕ) → (𝐴 mod 8)
∈ (0...(8 − 1))) | 
| 4 | 1, 2, 3 | sylancl 413 | 
. . 3
⊢ ((𝐴 ∈ ℤ ∧ ¬ 2
∥ 𝐴) → (𝐴 mod 8) ∈ (0...(8 −
1))) | 
| 5 |   | 8m1e7 9115 | 
. . . 4
⊢ (8
− 1) = 7 | 
| 6 | 5 | oveq2i 5933 | 
. . 3
⊢ (0...(8
− 1)) = (0...7) | 
| 7 | 4, 6 | eleqtrdi 2289 | 
. 2
⊢ ((𝐴 ∈ ℤ ∧ ¬ 2
∥ 𝐴) → (𝐴 mod 8) ∈
(0...7)) | 
| 8 |   | neg1z 9358 | 
. . . . . . . 8
⊢ -1 ∈
ℤ | 
| 9 |   | z0even 12076 | 
. . . . . . . . 9
⊢ 2 ∥
0 | 
| 10 |   | 1pneg1e0 9101 | 
. . . . . . . . . 10
⊢ (1 + -1)
= 0 | 
| 11 |   | ax-1cn 7972 | 
. . . . . . . . . . 11
⊢ 1 ∈
ℂ | 
| 12 |   | neg1cn 9095 | 
. . . . . . . . . . 11
⊢ -1 ∈
ℂ | 
| 13 | 11, 12 | addcomi 8170 | 
. . . . . . . . . 10
⊢ (1 + -1)
= (-1 + 1) | 
| 14 | 10, 13 | eqtr3i 2219 | 
. . . . . . . . 9
⊢ 0 = (-1 +
1) | 
| 15 | 9, 14 | breqtri 4058 | 
. . . . . . . 8
⊢ 2 ∥
(-1 + 1) | 
| 16 |   | noel 3454 | 
. . . . . . . . . . 11
⊢  ¬
(𝐴 mod 8) ∈
∅ | 
| 17 | 16 | pm2.21i 647 | 
. . . . . . . . . 10
⊢ ((𝐴 mod 8) ∈ ∅ →
(𝐴 mod 8) ∈ ({1, 7}
∪ {3, 5})) | 
| 18 |   | neg1lt0 9098 | 
. . . . . . . . . . 11
⊢ -1 <
0 | 
| 19 |   | 0z 9337 | 
. . . . . . . . . . . 12
⊢ 0 ∈
ℤ | 
| 20 |   | fzn 10117 | 
. . . . . . . . . . . 12
⊢ ((0
∈ ℤ ∧ -1 ∈ ℤ) → (-1 < 0 ↔ (0...-1) =
∅)) | 
| 21 | 19, 8, 20 | mp2an 426 | 
. . . . . . . . . . 11
⊢ (-1 <
0 ↔ (0...-1) = ∅) | 
| 22 | 18, 21 | mpbi 145 | 
. . . . . . . . . 10
⊢ (0...-1)
= ∅ | 
| 23 | 17, 22 | eleq2s 2291 | 
. . . . . . . . 9
⊢ ((𝐴 mod 8) ∈ (0...-1) →
(𝐴 mod 8) ∈ ({1, 7}
∪ {3, 5})) | 
| 24 | 23 | a1i 9 | 
. . . . . . . 8
⊢ ((𝐴 ∈ ℤ ∧ ¬ 2
∥ 𝐴) → ((𝐴 mod 8) ∈ (0...-1) →
(𝐴 mod 8) ∈ ({1, 7}
∪ {3, 5}))) | 
| 25 | 8, 15, 24 | 3pm3.2i 1177 | 
. . . . . . 7
⊢ (-1
∈ ℤ ∧ 2 ∥ (-1 + 1) ∧ ((𝐴 ∈ ℤ ∧ ¬ 2 ∥ 𝐴) → ((𝐴 mod 8) ∈ (0...-1) → (𝐴 mod 8) ∈ ({1, 7} ∪ {3,
5})))) | 
| 26 |   | 1e0p1 9498 | 
. . . . . . 7
⊢ 1 = (0 +
1) | 
| 27 |   | ssun1 3326 | 
. . . . . . . 8
⊢ {1, 7}
⊆ ({1, 7} ∪ {3, 5}) | 
| 28 |   | 1ex 8021 | 
. . . . . . . . 9
⊢ 1 ∈
V | 
| 29 | 28 | prid1 3728 | 
. . . . . . . 8
⊢ 1 ∈
{1, 7} | 
| 30 | 27, 29 | sselii 3180 | 
. . . . . . 7
⊢ 1 ∈
({1, 7} ∪ {3, 5}) | 
| 31 | 25, 14, 26, 30 | lgsdir2lem2 15270 | 
. . . . . 6
⊢ (1 ∈
ℤ ∧ 2 ∥ (1 + 1) ∧ ((𝐴 ∈ ℤ ∧ ¬ 2 ∥ 𝐴) → ((𝐴 mod 8) ∈ (0...1) → (𝐴 mod 8) ∈ ({1, 7} ∪ {3,
5})))) | 
| 32 |   | df-2 9049 | 
. . . . . 6
⊢ 2 = (1 +
1) | 
| 33 |   | df-3 9050 | 
. . . . . 6
⊢ 3 = (2 +
1) | 
| 34 |   | ssun2 3327 | 
. . . . . . 7
⊢ {3, 5}
⊆ ({1, 7} ∪ {3, 5}) | 
| 35 |   | 3ex 9066 | 
. . . . . . . 8
⊢ 3 ∈
V | 
| 36 | 35 | prid1 3728 | 
. . . . . . 7
⊢ 3 ∈
{3, 5} | 
| 37 | 34, 36 | sselii 3180 | 
. . . . . 6
⊢ 3 ∈
({1, 7} ∪ {3, 5}) | 
| 38 | 31, 32, 33, 37 | lgsdir2lem2 15270 | 
. . . . 5
⊢ (3 ∈
ℤ ∧ 2 ∥ (3 + 1) ∧ ((𝐴 ∈ ℤ ∧ ¬ 2 ∥ 𝐴) → ((𝐴 mod 8) ∈ (0...3) → (𝐴 mod 8) ∈ ({1, 7} ∪ {3,
5})))) | 
| 39 |   | df-4 9051 | 
. . . . 5
⊢ 4 = (3 +
1) | 
| 40 |   | df-5 9052 | 
. . . . 5
⊢ 5 = (4 +
1) | 
| 41 |   | 5nn 9155 | 
. . . . . . . 8
⊢ 5 ∈
ℕ | 
| 42 | 41 | elexi 2775 | 
. . . . . . 7
⊢ 5 ∈
V | 
| 43 | 42 | prid2 3729 | 
. . . . . 6
⊢ 5 ∈
{3, 5} | 
| 44 | 34, 43 | sselii 3180 | 
. . . . 5
⊢ 5 ∈
({1, 7} ∪ {3, 5}) | 
| 45 | 38, 39, 40, 44 | lgsdir2lem2 15270 | 
. . . 4
⊢ (5 ∈
ℤ ∧ 2 ∥ (5 + 1) ∧ ((𝐴 ∈ ℤ ∧ ¬ 2 ∥ 𝐴) → ((𝐴 mod 8) ∈ (0...5) → (𝐴 mod 8) ∈ ({1, 7} ∪ {3,
5})))) | 
| 46 |   | df-6 9053 | 
. . . 4
⊢ 6 = (5 +
1) | 
| 47 |   | df-7 9054 | 
. . . 4
⊢ 7 = (6 +
1) | 
| 48 |   | 7nn 9157 | 
. . . . . . 7
⊢ 7 ∈
ℕ | 
| 49 | 48 | elexi 2775 | 
. . . . . 6
⊢ 7 ∈
V | 
| 50 | 49 | prid2 3729 | 
. . . . 5
⊢ 7 ∈
{1, 7} | 
| 51 | 27, 50 | sselii 3180 | 
. . . 4
⊢ 7 ∈
({1, 7} ∪ {3, 5}) | 
| 52 | 45, 46, 47, 51 | lgsdir2lem2 15270 | 
. . 3
⊢ (7 ∈
ℤ ∧ 2 ∥ (7 + 1) ∧ ((𝐴 ∈ ℤ ∧ ¬ 2 ∥ 𝐴) → ((𝐴 mod 8) ∈ (0...7) → (𝐴 mod 8) ∈ ({1, 7} ∪ {3,
5})))) | 
| 53 | 52 | simp3i 1010 | 
. 2
⊢ ((𝐴 ∈ ℤ ∧ ¬ 2
∥ 𝐴) → ((𝐴 mod 8) ∈ (0...7) →
(𝐴 mod 8) ∈ ({1, 7}
∪ {3, 5}))) | 
| 54 | 7, 53 | mpd 13 | 
1
⊢ ((𝐴 ∈ ℤ ∧ ¬ 2
∥ 𝐴) → (𝐴 mod 8) ∈ ({1, 7} ∪ {3,
5})) |