| Step | Hyp | Ref
 | Expression | 
| 1 |   | elnn0 9251 | 
. . . 4
⊢ (𝑘 ∈ ℕ0
↔ (𝑘 ∈ ℕ
∨ 𝑘 =
0)) | 
| 2 |   | eleq1 2259 | 
. . . . . 6
⊢ (𝑗 = 1 → (𝑗 ∈ 𝑆 ↔ 1 ∈ 𝑆)) | 
| 3 |   | eleq1 2259 | 
. . . . . 6
⊢ (𝑗 = 𝑚 → (𝑗 ∈ 𝑆 ↔ 𝑚 ∈ 𝑆)) | 
| 4 |   | eleq1 2259 | 
. . . . . 6
⊢ (𝑗 = 𝑖 → (𝑗 ∈ 𝑆 ↔ 𝑖 ∈ 𝑆)) | 
| 5 |   | eleq1 2259 | 
. . . . . 6
⊢ (𝑗 = (𝑚 · 𝑖) → (𝑗 ∈ 𝑆 ↔ (𝑚 · 𝑖) ∈ 𝑆)) | 
| 6 |   | eleq1 2259 | 
. . . . . 6
⊢ (𝑗 = 𝑘 → (𝑗 ∈ 𝑆 ↔ 𝑘 ∈ 𝑆)) | 
| 7 |   | abs1 11237 | 
. . . . . . . . . . 11
⊢
(abs‘1) = 1 | 
| 8 | 7 | oveq1i 5932 | 
. . . . . . . . . 10
⊢
((abs‘1)↑2) = (1↑2) | 
| 9 |   | sq1 10725 | 
. . . . . . . . . 10
⊢
(1↑2) = 1 | 
| 10 | 8, 9 | eqtri 2217 | 
. . . . . . . . 9
⊢
((abs‘1)↑2) = 1 | 
| 11 |   | abs0 11223 | 
. . . . . . . . . . 11
⊢
(abs‘0) = 0 | 
| 12 | 11 | oveq1i 5932 | 
. . . . . . . . . 10
⊢
((abs‘0)↑2) = (0↑2) | 
| 13 |   | sq0 10722 | 
. . . . . . . . . 10
⊢
(0↑2) = 0 | 
| 14 | 12, 13 | eqtri 2217 | 
. . . . . . . . 9
⊢
((abs‘0)↑2) = 0 | 
| 15 | 10, 14 | oveq12i 5934 | 
. . . . . . . 8
⊢
(((abs‘1)↑2) + ((abs‘0)↑2)) = (1 +
0) | 
| 16 |   | 1p0e1 9106 | 
. . . . . . . 8
⊢ (1 + 0) =
1 | 
| 17 | 15, 16 | eqtri 2217 | 
. . . . . . 7
⊢
(((abs‘1)↑2) + ((abs‘0)↑2)) = 1 | 
| 18 |   | 1z 9352 | 
. . . . . . . . 9
⊢ 1 ∈
ℤ | 
| 19 |   | zgz 12542 | 
. . . . . . . . 9
⊢ (1 ∈
ℤ → 1 ∈ ℤ[i]) | 
| 20 | 18, 19 | ax-mp 5 | 
. . . . . . . 8
⊢ 1 ∈
ℤ[i] | 
| 21 |   | 0z 9337 | 
. . . . . . . . 9
⊢ 0 ∈
ℤ | 
| 22 |   | zgz 12542 | 
. . . . . . . . 9
⊢ (0 ∈
ℤ → 0 ∈ ℤ[i]) | 
| 23 | 21, 22 | ax-mp 5 | 
. . . . . . . 8
⊢ 0 ∈
ℤ[i] | 
| 24 |   | 4sqlem11.1 | 
. . . . . . . . 9
⊢ 𝑆 = {𝑛 ∣ ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ ∃𝑧 ∈ ℤ ∃𝑤 ∈ ℤ 𝑛 = (((𝑥↑2) + (𝑦↑2)) + ((𝑧↑2) + (𝑤↑2)))} | 
| 25 | 24 | 4sqlem4a 12560 | 
. . . . . . . 8
⊢ ((1
∈ ℤ[i] ∧ 0 ∈ ℤ[i]) → (((abs‘1)↑2) +
((abs‘0)↑2)) ∈ 𝑆) | 
| 26 | 20, 23, 25 | mp2an 426 | 
. . . . . . 7
⊢
(((abs‘1)↑2) + ((abs‘0)↑2)) ∈ 𝑆 | 
| 27 | 17, 26 | eqeltrri 2270 | 
. . . . . 6
⊢ 1 ∈
𝑆 | 
| 28 | 10, 10 | oveq12i 5934 | 
. . . . . . . . . 10
⊢
(((abs‘1)↑2) + ((abs‘1)↑2)) = (1 +
1) | 
| 29 |   | df-2 9049 | 
. . . . . . . . . 10
⊢ 2 = (1 +
1) | 
| 30 | 28, 29 | eqtr4i 2220 | 
. . . . . . . . 9
⊢
(((abs‘1)↑2) + ((abs‘1)↑2)) = 2 | 
| 31 | 24 | 4sqlem4a 12560 | 
. . . . . . . . . 10
⊢ ((1
∈ ℤ[i] ∧ 1 ∈ ℤ[i]) → (((abs‘1)↑2) +
((abs‘1)↑2)) ∈ 𝑆) | 
| 32 | 20, 20, 31 | mp2an 426 | 
. . . . . . . . 9
⊢
(((abs‘1)↑2) + ((abs‘1)↑2)) ∈ 𝑆 | 
| 33 | 30, 32 | eqeltrri 2270 | 
. . . . . . . 8
⊢ 2 ∈
𝑆 | 
| 34 |   | eleq1 2259 | 
. . . . . . . . 9
⊢ (𝑗 = 2 → (𝑗 ∈ 𝑆 ↔ 2 ∈ 𝑆)) | 
| 35 | 34 | adantl 277 | 
. . . . . . . 8
⊢ (((𝑗 ∈ ℙ ∧
∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) ∧ 𝑗 = 2) → (𝑗 ∈ 𝑆 ↔ 2 ∈ 𝑆)) | 
| 36 | 33, 35 | mpbiri 168 | 
. . . . . . 7
⊢ (((𝑗 ∈ ℙ ∧
∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) ∧ 𝑗 = 2) → 𝑗 ∈ 𝑆) | 
| 37 |   | eldifsn 3749 | 
. . . . . . . . 9
⊢ (𝑗 ∈ (ℙ ∖ {2})
↔ (𝑗 ∈ ℙ
∧ 𝑗 ≠
2)) | 
| 38 |   | oddprm 12428 | 
. . . . . . . . . . 11
⊢ (𝑗 ∈ (ℙ ∖ {2})
→ ((𝑗 − 1) / 2)
∈ ℕ) | 
| 39 | 38 | adantr 276 | 
. . . . . . . . . 10
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → ((𝑗 − 1) / 2) ∈
ℕ) | 
| 40 |   | eldifi 3285 | 
. . . . . . . . . . . . . . . 16
⊢ (𝑗 ∈ (ℙ ∖ {2})
→ 𝑗 ∈
ℙ) | 
| 41 | 40 | adantr 276 | 
. . . . . . . . . . . . . . 15
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → 𝑗 ∈ ℙ) | 
| 42 |   | prmnn 12278 | 
. . . . . . . . . . . . . . 15
⊢ (𝑗 ∈ ℙ → 𝑗 ∈
ℕ) | 
| 43 |   | nncn 8998 | 
. . . . . . . . . . . . . . 15
⊢ (𝑗 ∈ ℕ → 𝑗 ∈
ℂ) | 
| 44 | 41, 42, 43 | 3syl 17 | 
. . . . . . . . . . . . . 14
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → 𝑗 ∈ ℂ) | 
| 45 |   | ax-1cn 7972 | 
. . . . . . . . . . . . . 14
⊢ 1 ∈
ℂ | 
| 46 |   | subcl 8225 | 
. . . . . . . . . . . . . 14
⊢ ((𝑗 ∈ ℂ ∧ 1 ∈
ℂ) → (𝑗 −
1) ∈ ℂ) | 
| 47 | 44, 45, 46 | sylancl 413 | 
. . . . . . . . . . . . 13
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (𝑗 − 1) ∈ ℂ) | 
| 48 |   | 2cnd 9063 | 
. . . . . . . . . . . . 13
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → 2 ∈ ℂ) | 
| 49 |   | 2ap0 9083 | 
. . . . . . . . . . . . . 14
⊢ 2 #
0 | 
| 50 | 49 | a1i 9 | 
. . . . . . . . . . . . 13
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → 2 # 0) | 
| 51 | 47, 48, 50 | divcanap2d 8819 | 
. . . . . . . . . . . 12
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (2 · ((𝑗 − 1) / 2)) = (𝑗 − 1)) | 
| 52 | 51 | oveq1d 5937 | 
. . . . . . . . . . 11
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → ((2 · ((𝑗 − 1) / 2)) + 1) = ((𝑗 − 1) + 1)) | 
| 53 |   | npcan 8235 | 
. . . . . . . . . . . 12
⊢ ((𝑗 ∈ ℂ ∧ 1 ∈
ℂ) → ((𝑗 −
1) + 1) = 𝑗) | 
| 54 | 44, 45, 53 | sylancl 413 | 
. . . . . . . . . . 11
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → ((𝑗 − 1) + 1) = 𝑗) | 
| 55 | 52, 54 | eqtr2d 2230 | 
. . . . . . . . . 10
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → 𝑗 = ((2 · ((𝑗 − 1) / 2)) + 1)) | 
| 56 | 51 | oveq2d 5938 | 
. . . . . . . . . . . 12
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (0...(2 · ((𝑗 − 1) / 2))) = (0...(𝑗 − 1))) | 
| 57 |   | nnm1nn0 9290 | 
. . . . . . . . . . . . . . 15
⊢ (𝑗 ∈ ℕ → (𝑗 − 1) ∈
ℕ0) | 
| 58 | 41, 42, 57 | 3syl 17 | 
. . . . . . . . . . . . . 14
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (𝑗 − 1) ∈
ℕ0) | 
| 59 |   | elnn0uz 9639 | 
. . . . . . . . . . . . . 14
⊢ ((𝑗 − 1) ∈
ℕ0 ↔ (𝑗 − 1) ∈
(ℤ≥‘0)) | 
| 60 | 58, 59 | sylib 122 | 
. . . . . . . . . . . . 13
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (𝑗 − 1) ∈
(ℤ≥‘0)) | 
| 61 |   | eluzfz1 10106 | 
. . . . . . . . . . . . 13
⊢ ((𝑗 − 1) ∈
(ℤ≥‘0) → 0 ∈ (0...(𝑗 − 1))) | 
| 62 |   | fzsplit 10126 | 
. . . . . . . . . . . . 13
⊢ (0 ∈
(0...(𝑗 − 1)) →
(0...(𝑗 − 1)) =
((0...0) ∪ ((0 + 1)...(𝑗 − 1)))) | 
| 63 | 60, 61, 62 | 3syl 17 | 
. . . . . . . . . . . 12
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (0...(𝑗 − 1)) = ((0...0) ∪ ((0 +
1)...(𝑗 −
1)))) | 
| 64 | 56, 63 | eqtrd 2229 | 
. . . . . . . . . . 11
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (0...(2 · ((𝑗 − 1) / 2))) = ((0...0)
∪ ((0 + 1)...(𝑗 −
1)))) | 
| 65 |   | fz0sn 10196 | 
. . . . . . . . . . . . . 14
⊢ (0...0) =
{0} | 
| 66 | 14, 14 | oveq12i 5934 | 
. . . . . . . . . . . . . . . . 17
⊢
(((abs‘0)↑2) + ((abs‘0)↑2)) = (0 +
0) | 
| 67 |   | 00id 8167 | 
. . . . . . . . . . . . . . . . 17
⊢ (0 + 0) =
0 | 
| 68 | 66, 67 | eqtri 2217 | 
. . . . . . . . . . . . . . . 16
⊢
(((abs‘0)↑2) + ((abs‘0)↑2)) = 0 | 
| 69 | 24 | 4sqlem4a 12560 | 
. . . . . . . . . . . . . . . . 17
⊢ ((0
∈ ℤ[i] ∧ 0 ∈ ℤ[i]) → (((abs‘0)↑2) +
((abs‘0)↑2)) ∈ 𝑆) | 
| 70 | 23, 23, 69 | mp2an 426 | 
. . . . . . . . . . . . . . . 16
⊢
(((abs‘0)↑2) + ((abs‘0)↑2)) ∈ 𝑆 | 
| 71 | 68, 70 | eqeltrri 2270 | 
. . . . . . . . . . . . . . 15
⊢ 0 ∈
𝑆 | 
| 72 |   | snssi 3766 | 
. . . . . . . . . . . . . . 15
⊢ (0 ∈
𝑆 → {0} ⊆ 𝑆) | 
| 73 | 71, 72 | ax-mp 5 | 
. . . . . . . . . . . . . 14
⊢ {0}
⊆ 𝑆 | 
| 74 | 65, 73 | eqsstri 3215 | 
. . . . . . . . . . . . 13
⊢ (0...0)
⊆ 𝑆 | 
| 75 | 74 | a1i 9 | 
. . . . . . . . . . . 12
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (0...0) ⊆ 𝑆) | 
| 76 |   | 0p1e1 9104 | 
. . . . . . . . . . . . . 14
⊢ (0 + 1) =
1 | 
| 77 | 76 | oveq1i 5932 | 
. . . . . . . . . . . . 13
⊢ ((0 +
1)...(𝑗 − 1)) =
(1...(𝑗 −
1)) | 
| 78 |   | simpr 110 | 
. . . . . . . . . . . . . 14
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → ∀𝑚 ∈ (1...(𝑗 − 1))𝑚 ∈ 𝑆) | 
| 79 |   | dfss3 3173 | 
. . . . . . . . . . . . . 14
⊢
((1...(𝑗 − 1))
⊆ 𝑆 ↔
∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) | 
| 80 | 78, 79 | sylibr 134 | 
. . . . . . . . . . . . 13
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (1...(𝑗 − 1)) ⊆ 𝑆) | 
| 81 | 77, 80 | eqsstrid 3229 | 
. . . . . . . . . . . 12
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → ((0 + 1)...(𝑗 − 1)) ⊆ 𝑆) | 
| 82 | 75, 81 | unssd 3339 | 
. . . . . . . . . . 11
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → ((0...0) ∪ ((0 + 1)...(𝑗 − 1))) ⊆ 𝑆) | 
| 83 | 64, 82 | eqsstrd 3219 | 
. . . . . . . . . 10
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (0...(2 · ((𝑗 − 1) / 2))) ⊆ 𝑆) | 
| 84 |   | oveq1 5929 | 
. . . . . . . . . . . 12
⊢ (𝑘 = 𝑖 → (𝑘 · 𝑗) = (𝑖 · 𝑗)) | 
| 85 | 84 | eleq1d 2265 | 
. . . . . . . . . . 11
⊢ (𝑘 = 𝑖 → ((𝑘 · 𝑗) ∈ 𝑆 ↔ (𝑖 · 𝑗) ∈ 𝑆)) | 
| 86 | 85 | cbvrabv 2762 | 
. . . . . . . . . 10
⊢ {𝑘 ∈ ℕ ∣ (𝑘 · 𝑗) ∈ 𝑆} = {𝑖 ∈ ℕ ∣ (𝑖 · 𝑗) ∈ 𝑆} | 
| 87 |   | eqid 2196 | 
. . . . . . . . . 10
⊢
inf({𝑘 ∈
ℕ ∣ (𝑘 ·
𝑗) ∈ 𝑆}, ℝ, < ) = inf({𝑘 ∈ ℕ ∣ (𝑘 · 𝑗) ∈ 𝑆}, ℝ, < ) | 
| 88 | 24, 39, 55, 41, 83, 86, 87 | 4sqlem18 12577 | 
. . . . . . . . 9
⊢ ((𝑗 ∈ (ℙ ∖ {2})
∧ ∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → 𝑗 ∈ 𝑆) | 
| 89 | 37, 88 | sylanbr 285 | 
. . . . . . . 8
⊢ (((𝑗 ∈ ℙ ∧ 𝑗 ≠ 2) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚 ∈ 𝑆) → 𝑗 ∈ 𝑆) | 
| 90 | 89 | an32s 568 | 
. . . . . . 7
⊢ (((𝑗 ∈ ℙ ∧
∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) ∧ 𝑗 ≠ 2) → 𝑗 ∈ 𝑆) | 
| 91 |   | prmz 12279 | 
. . . . . . . . . 10
⊢ (𝑗 ∈ ℙ → 𝑗 ∈
ℤ) | 
| 92 | 91 | adantr 276 | 
. . . . . . . . 9
⊢ ((𝑗 ∈ ℙ ∧
∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → 𝑗 ∈ ℤ) | 
| 93 |   | 2z 9354 | 
. . . . . . . . 9
⊢ 2 ∈
ℤ | 
| 94 |   | zdceq 9401 | 
. . . . . . . . 9
⊢ ((𝑗 ∈ ℤ ∧ 2 ∈
ℤ) → DECID 𝑗 = 2) | 
| 95 | 92, 93, 94 | sylancl 413 | 
. . . . . . . 8
⊢ ((𝑗 ∈ ℙ ∧
∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → DECID 𝑗 = 2) | 
| 96 |   | dcne 2378 | 
. . . . . . . 8
⊢
(DECID 𝑗 = 2 ↔ (𝑗 = 2 ∨ 𝑗 ≠ 2)) | 
| 97 | 95, 96 | sylib 122 | 
. . . . . . 7
⊢ ((𝑗 ∈ ℙ ∧
∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → (𝑗 = 2 ∨ 𝑗 ≠ 2)) | 
| 98 | 36, 90, 97 | mpjaodan 799 | 
. . . . . 6
⊢ ((𝑗 ∈ ℙ ∧
∀𝑚 ∈
(1...(𝑗 − 1))𝑚 ∈ 𝑆) → 𝑗 ∈ 𝑆) | 
| 99 | 24 | mul4sq 12563 | 
. . . . . . 7
⊢ ((𝑚 ∈ 𝑆 ∧ 𝑖 ∈ 𝑆) → (𝑚 · 𝑖) ∈ 𝑆) | 
| 100 | 99 | a1i 9 | 
. . . . . 6
⊢ ((𝑚 ∈
(ℤ≥‘2) ∧ 𝑖 ∈ (ℤ≥‘2))
→ ((𝑚 ∈ 𝑆 ∧ 𝑖 ∈ 𝑆) → (𝑚 · 𝑖) ∈ 𝑆)) | 
| 101 | 2, 3, 4, 5, 6, 27,
98, 100 | prmind2 12288 | 
. . . . 5
⊢ (𝑘 ∈ ℕ → 𝑘 ∈ 𝑆) | 
| 102 |   | id 19 | 
. . . . . 6
⊢ (𝑘 = 0 → 𝑘 = 0) | 
| 103 | 102, 71 | eqeltrdi 2287 | 
. . . . 5
⊢ (𝑘 = 0 → 𝑘 ∈ 𝑆) | 
| 104 | 101, 103 | jaoi 717 | 
. . . 4
⊢ ((𝑘 ∈ ℕ ∨ 𝑘 = 0) → 𝑘 ∈ 𝑆) | 
| 105 | 1, 104 | sylbi 121 | 
. . 3
⊢ (𝑘 ∈ ℕ0
→ 𝑘 ∈ 𝑆) | 
| 106 | 105 | ssriv 3187 | 
. 2
⊢
ℕ0 ⊆ 𝑆 | 
| 107 | 24 | 4sqlem1 12557 | 
. 2
⊢ 𝑆 ⊆
ℕ0 | 
| 108 | 106, 107 | eqssi 3199 | 
1
⊢
ℕ0 = 𝑆 |