Proof of Theorem 2sqlem7
| Step | Hyp | Ref
| Expression |
| 1 | | 2sqlem7.2 |
. 2
⊢ 𝑌 = {𝑧 ∣ ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2)))} |
| 2 | | simpr 484 |
. . . . . . 7
⊢ (((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2))) → 𝑧 = ((𝑥↑2) + (𝑦↑2))) |
| 3 | 2 | reximi 3083 |
. . . . . 6
⊢
(∃𝑦 ∈
ℤ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2))) → ∃𝑦 ∈ ℤ 𝑧 = ((𝑥↑2) + (𝑦↑2))) |
| 4 | 3 | reximi 3083 |
. . . . 5
⊢
(∃𝑥 ∈
ℤ ∃𝑦 ∈
ℤ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2))) → ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ 𝑧 = ((𝑥↑2) + (𝑦↑2))) |
| 5 | | 2sq.1 |
. . . . . 6
⊢ 𝑆 = ran (𝑤 ∈ ℤ[i] ↦ ((abs‘𝑤)↑2)) |
| 6 | 5 | 2sqlem2 27463 |
. . . . 5
⊢ (𝑧 ∈ 𝑆 ↔ ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ 𝑧 = ((𝑥↑2) + (𝑦↑2))) |
| 7 | 4, 6 | sylibr 234 |
. . . 4
⊢
(∃𝑥 ∈
ℤ ∃𝑦 ∈
ℤ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2))) → 𝑧 ∈ 𝑆) |
| 8 | | ax-1ne0 11225 |
. . . . . . . . . 10
⊢ 1 ≠
0 |
| 9 | | gcdeq0 16555 |
. . . . . . . . . . . . 13
⊢ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) → ((𝑥 gcd 𝑦) = 0 ↔ (𝑥 = 0 ∧ 𝑦 = 0))) |
| 10 | 9 | adantr 480 |
. . . . . . . . . . . 12
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → ((𝑥 gcd 𝑦) = 0 ↔ (𝑥 = 0 ∧ 𝑦 = 0))) |
| 11 | | simpr 484 |
. . . . . . . . . . . . 13
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (𝑥 gcd 𝑦) = 1) |
| 12 | 11 | eqeq1d 2738 |
. . . . . . . . . . . 12
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → ((𝑥 gcd 𝑦) = 0 ↔ 1 = 0)) |
| 13 | 10, 12 | bitr3d 281 |
. . . . . . . . . . 11
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → ((𝑥 = 0 ∧ 𝑦 = 0) ↔ 1 = 0)) |
| 14 | 13 | necon3bbid 2977 |
. . . . . . . . . 10
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (¬ (𝑥 = 0 ∧ 𝑦 = 0) ↔ 1 ≠ 0)) |
| 15 | 8, 14 | mpbiri 258 |
. . . . . . . . 9
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → ¬ (𝑥 = 0 ∧ 𝑦 = 0)) |
| 16 | | zsqcl2 14179 |
. . . . . . . . . . . . 13
⊢ (𝑥 ∈ ℤ → (𝑥↑2) ∈
ℕ0) |
| 17 | 16 | ad2antrr 726 |
. . . . . . . . . . . 12
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (𝑥↑2) ∈
ℕ0) |
| 18 | 17 | nn0red 12590 |
. . . . . . . . . . 11
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (𝑥↑2) ∈ ℝ) |
| 19 | 17 | nn0ge0d 12592 |
. . . . . . . . . . 11
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → 0 ≤ (𝑥↑2)) |
| 20 | | zsqcl2 14179 |
. . . . . . . . . . . . 13
⊢ (𝑦 ∈ ℤ → (𝑦↑2) ∈
ℕ0) |
| 21 | 20 | ad2antlr 727 |
. . . . . . . . . . . 12
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (𝑦↑2) ∈
ℕ0) |
| 22 | 21 | nn0red 12590 |
. . . . . . . . . . 11
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (𝑦↑2) ∈ ℝ) |
| 23 | 21 | nn0ge0d 12592 |
. . . . . . . . . . 11
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → 0 ≤ (𝑦↑2)) |
| 24 | | add20 11776 |
. . . . . . . . . . 11
⊢ ((((𝑥↑2) ∈ ℝ ∧ 0
≤ (𝑥↑2)) ∧
((𝑦↑2) ∈ ℝ
∧ 0 ≤ (𝑦↑2)))
→ (((𝑥↑2) +
(𝑦↑2)) = 0 ↔
((𝑥↑2) = 0 ∧
(𝑦↑2) =
0))) |
| 25 | 18, 19, 22, 23, 24 | syl22anc 838 |
. . . . . . . . . 10
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (((𝑥↑2) + (𝑦↑2)) = 0 ↔ ((𝑥↑2) = 0 ∧ (𝑦↑2) = 0))) |
| 26 | | zcn 12620 |
. . . . . . . . . . . 12
⊢ (𝑥 ∈ ℤ → 𝑥 ∈
ℂ) |
| 27 | 26 | ad2antrr 726 |
. . . . . . . . . . 11
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → 𝑥 ∈ ℂ) |
| 28 | | zcn 12620 |
. . . . . . . . . . . 12
⊢ (𝑦 ∈ ℤ → 𝑦 ∈
ℂ) |
| 29 | 28 | ad2antlr 727 |
. . . . . . . . . . 11
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → 𝑦 ∈ ℂ) |
| 30 | | sqeq0 14161 |
. . . . . . . . . . . 12
⊢ (𝑥 ∈ ℂ → ((𝑥↑2) = 0 ↔ 𝑥 = 0)) |
| 31 | | sqeq0 14161 |
. . . . . . . . . . . 12
⊢ (𝑦 ∈ ℂ → ((𝑦↑2) = 0 ↔ 𝑦 = 0)) |
| 32 | 30, 31 | bi2anan9 638 |
. . . . . . . . . . 11
⊢ ((𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ) → (((𝑥↑2) = 0 ∧ (𝑦↑2) = 0) ↔ (𝑥 = 0 ∧ 𝑦 = 0))) |
| 33 | 27, 29, 32 | syl2anc 584 |
. . . . . . . . . 10
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (((𝑥↑2) = 0 ∧ (𝑦↑2) = 0) ↔ (𝑥 = 0 ∧ 𝑦 = 0))) |
| 34 | 25, 33 | bitrd 279 |
. . . . . . . . 9
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (((𝑥↑2) + (𝑦↑2)) = 0 ↔ (𝑥 = 0 ∧ 𝑦 = 0))) |
| 35 | 15, 34 | mtbird 325 |
. . . . . . . 8
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → ¬ ((𝑥↑2) + (𝑦↑2)) = 0) |
| 36 | | nn0addcl 12563 |
. . . . . . . . . . . 12
⊢ (((𝑥↑2) ∈
ℕ0 ∧ (𝑦↑2) ∈ ℕ0) →
((𝑥↑2) + (𝑦↑2)) ∈
ℕ0) |
| 37 | 16, 20, 36 | syl2an 596 |
. . . . . . . . . . 11
⊢ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) → ((𝑥↑2) + (𝑦↑2)) ∈
ℕ0) |
| 38 | 37 | adantr 480 |
. . . . . . . . . 10
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → ((𝑥↑2) + (𝑦↑2)) ∈
ℕ0) |
| 39 | | elnn0 12530 |
. . . . . . . . . 10
⊢ (((𝑥↑2) + (𝑦↑2)) ∈ ℕ0 ↔
(((𝑥↑2) + (𝑦↑2)) ∈ ℕ ∨
((𝑥↑2) + (𝑦↑2)) = 0)) |
| 40 | 38, 39 | sylib 218 |
. . . . . . . . 9
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (((𝑥↑2) + (𝑦↑2)) ∈ ℕ ∨ ((𝑥↑2) + (𝑦↑2)) = 0)) |
| 41 | 40 | ord 864 |
. . . . . . . 8
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (¬ ((𝑥↑2) + (𝑦↑2)) ∈ ℕ → ((𝑥↑2) + (𝑦↑2)) = 0)) |
| 42 | 35, 41 | mt3d 148 |
. . . . . . 7
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → ((𝑥↑2) + (𝑦↑2)) ∈ ℕ) |
| 43 | | eleq1 2828 |
. . . . . . 7
⊢ (𝑧 = ((𝑥↑2) + (𝑦↑2)) → (𝑧 ∈ ℕ ↔ ((𝑥↑2) + (𝑦↑2)) ∈ ℕ)) |
| 44 | 42, 43 | syl5ibrcom 247 |
. . . . . 6
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) ∧ (𝑥 gcd 𝑦) = 1) → (𝑧 = ((𝑥↑2) + (𝑦↑2)) → 𝑧 ∈ ℕ)) |
| 45 | 44 | expimpd 453 |
. . . . 5
⊢ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) → (((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2))) → 𝑧 ∈ ℕ)) |
| 46 | 45 | rexlimivv 3200 |
. . . 4
⊢
(∃𝑥 ∈
ℤ ∃𝑦 ∈
ℤ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2))) → 𝑧 ∈ ℕ) |
| 47 | 7, 46 | elind 4199 |
. . 3
⊢
(∃𝑥 ∈
ℤ ∃𝑦 ∈
ℤ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2))) → 𝑧 ∈ (𝑆 ∩ ℕ)) |
| 48 | 47 | abssi 4069 |
. 2
⊢ {𝑧 ∣ ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2)))} ⊆ (𝑆 ∩ ℕ) |
| 49 | 1, 48 | eqsstri 4029 |
1
⊢ 𝑌 ⊆ (𝑆 ∩ ℕ) |