| Step | Hyp | Ref
 | Expression | 
| 1 |   | ax-1cn 7972 | 
. . . . . 6
⊢ 1 ∈
ℂ | 
| 2 |   | 1ap0 8617 | 
. . . . . 6
⊢ 1 #
0 | 
| 3 | 1, 2 | div0api 8773 | 
. . . . 5
⊢ (0 / 1) =
0 | 
| 4 |   | 0z 9337 | 
. . . . . 6
⊢ 0 ∈
ℤ | 
| 5 |   | 1nn 9001 | 
. . . . . 6
⊢ 1 ∈
ℕ | 
| 6 |   | znq 9698 | 
. . . . . 6
⊢ ((0
∈ ℤ ∧ 1 ∈ ℕ) → (0 / 1) ∈
ℚ) | 
| 7 | 4, 5, 6 | mp2an 426 | 
. . . . 5
⊢ (0 / 1)
∈ ℚ | 
| 8 | 3, 7 | eqeltrri 2270 | 
. . . 4
⊢ 0 ∈
ℚ | 
| 9 |   | qapne 9713 | 
. . . 4
⊢ ((𝐴 ∈ ℚ ∧ 0 ∈
ℚ) → (𝐴 # 0
↔ 𝐴 ≠
0)) | 
| 10 | 8, 9 | mpan2 425 | 
. . 3
⊢ (𝐴 ∈ ℚ → (𝐴 # 0 ↔ 𝐴 ≠ 0)) | 
| 11 | 10 | biimpar 297 | 
. 2
⊢ ((𝐴 ∈ ℚ ∧ 𝐴 ≠ 0) → 𝐴 # 0) | 
| 12 |   | elq 9696 | 
. . . 4
⊢ (𝐴 ∈ ℚ ↔
∃𝑥 ∈ ℤ
∃𝑦 ∈ ℕ
𝐴 = (𝑥 / 𝑦)) | 
| 13 |   | nnne0 9018 | 
. . . . . . . 8
⊢ (𝑦 ∈ ℕ → 𝑦 ≠ 0) | 
| 14 | 13 | ancli 323 | 
. . . . . . 7
⊢ (𝑦 ∈ ℕ → (𝑦 ∈ ℕ ∧ 𝑦 ≠ 0)) | 
| 15 |   | nnz 9345 | 
. . . . . . . . . . . . . . . 16
⊢ (𝑦 ∈ ℕ → 𝑦 ∈
ℤ) | 
| 16 |   | zapne 9400 | 
. . . . . . . . . . . . . . . 16
⊢ ((𝑦 ∈ ℤ ∧ 0 ∈
ℤ) → (𝑦 # 0
↔ 𝑦 ≠
0)) | 
| 17 | 15, 4, 16 | sylancl 413 | 
. . . . . . . . . . . . . . 15
⊢ (𝑦 ∈ ℕ → (𝑦 # 0 ↔ 𝑦 ≠ 0)) | 
| 18 | 17 | adantl 277 | 
. . . . . . . . . . . . . 14
⊢ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) → (𝑦 # 0 ↔ 𝑦 ≠ 0)) | 
| 19 | 18 | pm5.32i 454 | 
. . . . . . . . . . . . 13
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 # 0) ↔ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0)) | 
| 20 | 19 | anbi1i 458 | 
. . . . . . . . . . . 12
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 # 0) ∧ 𝐴 = (𝑥 / 𝑦)) ↔ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦))) | 
| 21 |   | breq1 4036 | 
. . . . . . . . . . . . 13
⊢ (𝐴 = (𝑥 / 𝑦) → (𝐴 # 0 ↔ (𝑥 / 𝑦) # 0)) | 
| 22 |   | zcn 9331 | 
. . . . . . . . . . . . . . . 16
⊢ (𝑥 ∈ ℤ → 𝑥 ∈
ℂ) | 
| 23 |   | nncn 8998 | 
. . . . . . . . . . . . . . . 16
⊢ (𝑦 ∈ ℕ → 𝑦 ∈
ℂ) | 
| 24 | 22, 23 | anim12i 338 | 
. . . . . . . . . . . . . . 15
⊢ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) → (𝑥 ∈ ℂ ∧ 𝑦 ∈
ℂ)) | 
| 25 |   | divap0b 8710 | 
. . . . . . . . . . . . . . . 16
⊢ ((𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ ∧ 𝑦 # 0) → (𝑥 # 0 ↔ (𝑥 / 𝑦) # 0)) | 
| 26 | 25 | 3expa 1205 | 
. . . . . . . . . . . . . . 15
⊢ (((𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ) ∧ 𝑦 # 0) → (𝑥 # 0 ↔ (𝑥 / 𝑦) # 0)) | 
| 27 | 24, 26 | sylan 283 | 
. . . . . . . . . . . . . 14
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 # 0) → (𝑥 # 0 ↔ (𝑥 / 𝑦) # 0)) | 
| 28 | 27 | bicomd 141 | 
. . . . . . . . . . . . 13
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 # 0) → ((𝑥 / 𝑦) # 0 ↔ 𝑥 # 0)) | 
| 29 | 21, 28 | sylan9bbr 463 | 
. . . . . . . . . . . 12
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 # 0) ∧ 𝐴 = (𝑥 / 𝑦)) → (𝐴 # 0 ↔ 𝑥 # 0)) | 
| 30 | 20, 29 | sylbir 135 | 
. . . . . . . . . . 11
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦)) → (𝐴 # 0 ↔ 𝑥 # 0)) | 
| 31 |   | simplll 533 | 
. . . . . . . . . . . 12
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦)) → 𝑥 ∈ ℤ) | 
| 32 |   | zapne 9400 | 
. . . . . . . . . . . 12
⊢ ((𝑥 ∈ ℤ ∧ 0 ∈
ℤ) → (𝑥 # 0
↔ 𝑥 ≠
0)) | 
| 33 | 31, 4, 32 | sylancl 413 | 
. . . . . . . . . . 11
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦)) → (𝑥 # 0 ↔ 𝑥 ≠ 0)) | 
| 34 | 30, 33 | bitrd 188 | 
. . . . . . . . . 10
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦)) → (𝐴 # 0 ↔ 𝑥 ≠ 0)) | 
| 35 |   | zmulcl 9379 | 
. . . . . . . . . . . . . . . . 17
⊢ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℤ) → (𝑥 · 𝑦) ∈ ℤ) | 
| 36 | 15, 35 | sylan2 286 | 
. . . . . . . . . . . . . . . 16
⊢ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) → (𝑥 · 𝑦) ∈ ℤ) | 
| 37 | 36 | adantr 276 | 
. . . . . . . . . . . . . . 15
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑥 ≠ 0) → (𝑥 · 𝑦) ∈ ℤ) | 
| 38 |   | msqznn 9426 | 
. . . . . . . . . . . . . . . 16
⊢ ((𝑥 ∈ ℤ ∧ 𝑥 ≠ 0) → (𝑥 · 𝑥) ∈ ℕ) | 
| 39 | 38 | adantlr 477 | 
. . . . . . . . . . . . . . 15
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑥 ≠ 0) → (𝑥 · 𝑥) ∈ ℕ) | 
| 40 | 37, 39 | jca 306 | 
. . . . . . . . . . . . . 14
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑥 ≠ 0) → ((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ)) | 
| 41 | 40 | adantlr 477 | 
. . . . . . . . . . . . 13
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝑥 ≠ 0) → ((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ)) | 
| 42 | 41 | adantlr 477 | 
. . . . . . . . . . . 12
⊢
(((((𝑥 ∈
ℤ ∧ 𝑦 ∈
ℕ) ∧ 𝑦 ≠ 0)
∧ 𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 ≠ 0) → ((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ)) | 
| 43 | 20 | anbi1i 458 | 
. . . . . . . . . . . . . 14
⊢
(((((𝑥 ∈
ℤ ∧ 𝑦 ∈
ℕ) ∧ 𝑦 # 0) ∧
𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 # 0) ↔ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 # 0)) | 
| 44 | 33 | pm5.32i 454 | 
. . . . . . . . . . . . . 14
⊢
(((((𝑥 ∈
ℤ ∧ 𝑦 ∈
ℕ) ∧ 𝑦 ≠ 0)
∧ 𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 # 0) ↔ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 ≠ 0)) | 
| 45 | 43, 44 | bitri 184 | 
. . . . . . . . . . . . 13
⊢
(((((𝑥 ∈
ℤ ∧ 𝑦 ∈
ℕ) ∧ 𝑦 # 0) ∧
𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 # 0) ↔ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 ≠ 0)) | 
| 46 |   | oveq2 5930 | 
. . . . . . . . . . . . . . 15
⊢ (𝐴 = (𝑥 / 𝑦) → (1 / 𝐴) = (1 / (𝑥 / 𝑦))) | 
| 47 |   | dividap 8728 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ ((𝑥 ∈ ℂ ∧ 𝑥 # 0) → (𝑥 / 𝑥) = 1) | 
| 48 | 47 | adantr 276 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (((𝑥 ∈ ℂ ∧ 𝑥 # 0) ∧ (𝑦 ∈ ℂ ∧ 𝑦 # 0)) → (𝑥 / 𝑥) = 1) | 
| 49 | 48 | oveq1d 5937 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (((𝑥 ∈ ℂ ∧ 𝑥 # 0) ∧ (𝑦 ∈ ℂ ∧ 𝑦 # 0)) → ((𝑥 / 𝑥) / (𝑥 / 𝑦)) = (1 / (𝑥 / 𝑦))) | 
| 50 |   | simpll 527 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (((𝑥 ∈ ℂ ∧ 𝑥 # 0) ∧ (𝑦 ∈ ℂ ∧ 𝑦 # 0)) → 𝑥 ∈ ℂ) | 
| 51 |   | simpl 109 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (((𝑥 ∈ ℂ ∧ 𝑥 # 0) ∧ (𝑦 ∈ ℂ ∧ 𝑦 # 0)) → (𝑥 ∈ ℂ ∧ 𝑥 # 0)) | 
| 52 |   | simpr 110 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (((𝑥 ∈ ℂ ∧ 𝑥 # 0) ∧ (𝑦 ∈ ℂ ∧ 𝑦 # 0)) → (𝑦 ∈ ℂ ∧ 𝑦 # 0)) | 
| 53 |   | divdivdivap 8740 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (((𝑥 ∈ ℂ ∧ (𝑥 ∈ ℂ ∧ 𝑥 # 0)) ∧ ((𝑥 ∈ ℂ ∧ 𝑥 # 0) ∧ (𝑦 ∈ ℂ ∧ 𝑦 # 0))) → ((𝑥 / 𝑥) / (𝑥 / 𝑦)) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) | 
| 54 | 50, 51, 51, 52, 53 | syl22anc 1250 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (((𝑥 ∈ ℂ ∧ 𝑥 # 0) ∧ (𝑦 ∈ ℂ ∧ 𝑦 # 0)) → ((𝑥 / 𝑥) / (𝑥 / 𝑦)) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) | 
| 55 | 49, 54 | eqtr3d 2231 | 
. . . . . . . . . . . . . . . . . 18
⊢ (((𝑥 ∈ ℂ ∧ 𝑥 # 0) ∧ (𝑦 ∈ ℂ ∧ 𝑦 # 0)) → (1 / (𝑥 / 𝑦)) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) | 
| 56 | 55 | an4s 588 | 
. . . . . . . . . . . . . . . . 17
⊢ (((𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ) ∧ (𝑥 # 0 ∧ 𝑦 # 0)) → (1 / (𝑥 / 𝑦)) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) | 
| 57 | 24, 56 | sylan 283 | 
. . . . . . . . . . . . . . . 16
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ (𝑥 # 0 ∧ 𝑦 # 0)) → (1 / (𝑥 / 𝑦)) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) | 
| 58 | 57 | anass1rs 571 | 
. . . . . . . . . . . . . . 15
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 # 0) ∧ 𝑥 # 0) → (1 / (𝑥 / 𝑦)) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) | 
| 59 | 46, 58 | sylan9eqr 2251 | 
. . . . . . . . . . . . . 14
⊢
(((((𝑥 ∈
ℤ ∧ 𝑦 ∈
ℕ) ∧ 𝑦 # 0) ∧
𝑥 # 0) ∧ 𝐴 = (𝑥 / 𝑦)) → (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) | 
| 60 | 59 | an32s 568 | 
. . . . . . . . . . . . 13
⊢
(((((𝑥 ∈
ℤ ∧ 𝑦 ∈
ℕ) ∧ 𝑦 # 0) ∧
𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 # 0) → (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) | 
| 61 | 45, 60 | sylbir 135 | 
. . . . . . . . . . . 12
⊢
(((((𝑥 ∈
ℤ ∧ 𝑦 ∈
ℕ) ∧ 𝑦 ≠ 0)
∧ 𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 ≠ 0) → (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) | 
| 62 | 42, 61 | jca 306 | 
. . . . . . . . . . 11
⊢
(((((𝑥 ∈
ℤ ∧ 𝑦 ∈
ℕ) ∧ 𝑦 ≠ 0)
∧ 𝐴 = (𝑥 / 𝑦)) ∧ 𝑥 ≠ 0) → (((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ) ∧ (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥)))) | 
| 63 | 62 | ex 115 | 
. . . . . . . . . 10
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦)) → (𝑥 ≠ 0 → (((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ) ∧ (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))))) | 
| 64 | 34, 63 | sylbid 150 | 
. . . . . . . . 9
⊢ ((((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) ∧ 𝐴 = (𝑥 / 𝑦)) → (𝐴 # 0 → (((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ) ∧ (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))))) | 
| 65 | 64 | ex 115 | 
. . . . . . . 8
⊢ (((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) ∧ 𝑦 ≠ 0) → (𝐴 = (𝑥 / 𝑦) → (𝐴 # 0 → (((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ) ∧ (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥)))))) | 
| 66 | 65 | anasss 399 | 
. . . . . . 7
⊢ ((𝑥 ∈ ℤ ∧ (𝑦 ∈ ℕ ∧ 𝑦 ≠ 0)) → (𝐴 = (𝑥 / 𝑦) → (𝐴 # 0 → (((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ) ∧ (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥)))))) | 
| 67 | 14, 66 | sylan2 286 | 
. . . . . 6
⊢ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) → (𝐴 = (𝑥 / 𝑦) → (𝐴 # 0 → (((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ) ∧ (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥)))))) | 
| 68 |   | rspceov 5964 | 
. . . . . . . 8
⊢ (((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ ∧ (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) → ∃𝑧 ∈ ℤ ∃𝑤 ∈ ℕ (1 / 𝐴) = (𝑧 / 𝑤)) | 
| 69 | 68 | 3expa 1205 | 
. . . . . . 7
⊢ ((((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ) ∧ (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) → ∃𝑧 ∈ ℤ ∃𝑤 ∈ ℕ (1 / 𝐴) = (𝑧 / 𝑤)) | 
| 70 |   | elq 9696 | 
. . . . . . 7
⊢ ((1 /
𝐴) ∈ ℚ ↔
∃𝑧 ∈ ℤ
∃𝑤 ∈ ℕ (1
/ 𝐴) = (𝑧 / 𝑤)) | 
| 71 | 69, 70 | sylibr 134 | 
. . . . . 6
⊢ ((((𝑥 · 𝑦) ∈ ℤ ∧ (𝑥 · 𝑥) ∈ ℕ) ∧ (1 / 𝐴) = ((𝑥 · 𝑦) / (𝑥 · 𝑥))) → (1 / 𝐴) ∈ ℚ) | 
| 72 | 67, 71 | syl8 71 | 
. . . . 5
⊢ ((𝑥 ∈ ℤ ∧ 𝑦 ∈ ℕ) → (𝐴 = (𝑥 / 𝑦) → (𝐴 # 0 → (1 / 𝐴) ∈ ℚ))) | 
| 73 | 72 | rexlimivv 2620 | 
. . . 4
⊢
(∃𝑥 ∈
ℤ ∃𝑦 ∈
ℕ 𝐴 = (𝑥 / 𝑦) → (𝐴 # 0 → (1 / 𝐴) ∈ ℚ)) | 
| 74 | 12, 73 | sylbi 121 | 
. . 3
⊢ (𝐴 ∈ ℚ → (𝐴 # 0 → (1 / 𝐴) ∈
ℚ)) | 
| 75 | 74 | imp 124 | 
. 2
⊢ ((𝐴 ∈ ℚ ∧ 𝐴 # 0) → (1 / 𝐴) ∈
ℚ) | 
| 76 | 11, 75 | syldan 282 | 
1
⊢ ((𝐴 ∈ ℚ ∧ 𝐴 ≠ 0) → (1 / 𝐴) ∈
ℚ) |