| Step | Hyp | Ref
 | Expression | 
| 1 |   | elq 9696 | 
. . . . 5
⊢ (𝐴 ∈ ℚ ↔
∃𝑧 ∈ ℤ
∃𝑦 ∈ ℕ
𝐴 = (𝑧 / 𝑦)) | 
| 2 |   | rexcom 2661 | 
. . . . 5
⊢
(∃𝑧 ∈
ℤ ∃𝑦 ∈
ℕ 𝐴 = (𝑧 / 𝑦) ↔ ∃𝑦 ∈ ℕ ∃𝑧 ∈ ℤ 𝐴 = (𝑧 / 𝑦)) | 
| 3 | 1, 2 | bitri 184 | 
. . . 4
⊢ (𝐴 ∈ ℚ ↔
∃𝑦 ∈ ℕ
∃𝑧 ∈ ℤ
𝐴 = (𝑧 / 𝑦)) | 
| 4 |   | breq2 4037 | 
. . . . . . . . . . 11
⊢ (𝐴 = (𝑧 / 𝑦) → (0 < 𝐴 ↔ 0 < (𝑧 / 𝑦))) | 
| 5 |   | zre 9330 | 
. . . . . . . . . . . . . 14
⊢ (𝑧 ∈ ℤ → 𝑧 ∈
ℝ) | 
| 6 | 5 | adantl 277 | 
. . . . . . . . . . . . 13
⊢ ((𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ) → 𝑧 ∈
ℝ) | 
| 7 |   | nnre 8997 | 
. . . . . . . . . . . . . 14
⊢ (𝑦 ∈ ℕ → 𝑦 ∈
ℝ) | 
| 8 | 7 | adantr 276 | 
. . . . . . . . . . . . 13
⊢ ((𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ) → 𝑦 ∈
ℝ) | 
| 9 |   | nngt0 9015 | 
. . . . . . . . . . . . . 14
⊢ (𝑦 ∈ ℕ → 0 <
𝑦) | 
| 10 | 9 | adantr 276 | 
. . . . . . . . . . . . 13
⊢ ((𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ) → 0 <
𝑦) | 
| 11 |   | gt0div 8897 | 
. . . . . . . . . . . . 13
⊢ ((𝑧 ∈ ℝ ∧ 𝑦 ∈ ℝ ∧ 0 <
𝑦) → (0 < 𝑧 ↔ 0 < (𝑧 / 𝑦))) | 
| 12 | 6, 8, 10, 11 | syl3anc 1249 | 
. . . . . . . . . . . 12
⊢ ((𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ) → (0 <
𝑧 ↔ 0 < (𝑧 / 𝑦))) | 
| 13 | 12 | bicomd 141 | 
. . . . . . . . . . 11
⊢ ((𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ) → (0 <
(𝑧 / 𝑦) ↔ 0 < 𝑧)) | 
| 14 | 4, 13 | sylan9bb 462 | 
. . . . . . . . . 10
⊢ ((𝐴 = (𝑧 / 𝑦) ∧ (𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ)) → (0 < 𝐴 ↔ 0 < 𝑧)) | 
| 15 |   | elnnz 9336 | 
. . . . . . . . . . . . . . . 16
⊢ (𝑧 ∈ ℕ ↔ (𝑧 ∈ ℤ ∧ 0 <
𝑧)) | 
| 16 | 15 | simplbi2 385 | 
. . . . . . . . . . . . . . 15
⊢ (𝑧 ∈ ℤ → (0 <
𝑧 → 𝑧 ∈ ℕ)) | 
| 17 | 16 | adantl 277 | 
. . . . . . . . . . . . . 14
⊢ ((𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ) → (0 <
𝑧 → 𝑧 ∈ ℕ)) | 
| 18 | 17 | adantl 277 | 
. . . . . . . . . . . . 13
⊢ ((𝐴 = (𝑧 / 𝑦) ∧ (𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ)) → (0 < 𝑧 → 𝑧 ∈ ℕ)) | 
| 19 | 18 | imp 124 | 
. . . . . . . . . . . 12
⊢ (((𝐴 = (𝑧 / 𝑦) ∧ (𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ)) ∧ 0 < 𝑧) → 𝑧 ∈ ℕ) | 
| 20 |   | oveq1 5929 | 
. . . . . . . . . . . . . 14
⊢ (𝑥 = 𝑧 → (𝑥 / 𝑦) = (𝑧 / 𝑦)) | 
| 21 | 20 | eqeq2d 2208 | 
. . . . . . . . . . . . 13
⊢ (𝑥 = 𝑧 → (𝐴 = (𝑥 / 𝑦) ↔ 𝐴 = (𝑧 / 𝑦))) | 
| 22 | 21 | adantl 277 | 
. . . . . . . . . . . 12
⊢ ((((𝐴 = (𝑧 / 𝑦) ∧ (𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ)) ∧ 0 < 𝑧) ∧ 𝑥 = 𝑧) → (𝐴 = (𝑥 / 𝑦) ↔ 𝐴 = (𝑧 / 𝑦))) | 
| 23 |   | simpll 527 | 
. . . . . . . . . . . 12
⊢ (((𝐴 = (𝑧 / 𝑦) ∧ (𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ)) ∧ 0 < 𝑧) → 𝐴 = (𝑧 / 𝑦)) | 
| 24 | 19, 22, 23 | rspcedvd 2874 | 
. . . . . . . . . . 11
⊢ (((𝐴 = (𝑧 / 𝑦) ∧ (𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ)) ∧ 0 < 𝑧) → ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦)) | 
| 25 | 24 | ex 115 | 
. . . . . . . . . 10
⊢ ((𝐴 = (𝑧 / 𝑦) ∧ (𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ)) → (0 < 𝑧 → ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦))) | 
| 26 | 14, 25 | sylbid 150 | 
. . . . . . . . 9
⊢ ((𝐴 = (𝑧 / 𝑦) ∧ (𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ)) → (0 < 𝐴 → ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦))) | 
| 27 | 26 | ex 115 | 
. . . . . . . 8
⊢ (𝐴 = (𝑧 / 𝑦) → ((𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ) → (0 < 𝐴 → ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦)))) | 
| 28 | 27 | com13 80 | 
. . . . . . 7
⊢ (0 <
𝐴 → ((𝑦 ∈ ℕ ∧ 𝑧 ∈ ℤ) → (𝐴 = (𝑧 / 𝑦) → ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦)))) | 
| 29 | 28 | impl 380 | 
. . . . . 6
⊢ (((0 <
𝐴 ∧ 𝑦 ∈ ℕ) ∧ 𝑧 ∈ ℤ) → (𝐴 = (𝑧 / 𝑦) → ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦))) | 
| 30 | 29 | rexlimdva 2614 | 
. . . . 5
⊢ ((0 <
𝐴 ∧ 𝑦 ∈ ℕ) → (∃𝑧 ∈ ℤ 𝐴 = (𝑧 / 𝑦) → ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦))) | 
| 31 | 30 | reximdva 2599 | 
. . . 4
⊢ (0 <
𝐴 → (∃𝑦 ∈ ℕ ∃𝑧 ∈ ℤ 𝐴 = (𝑧 / 𝑦) → ∃𝑦 ∈ ℕ ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦))) | 
| 32 | 3, 31 | biimtrid 152 | 
. . 3
⊢ (0 <
𝐴 → (𝐴 ∈ ℚ → ∃𝑦 ∈ ℕ ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦))) | 
| 33 | 32 | impcom 125 | 
. 2
⊢ ((𝐴 ∈ ℚ ∧ 0 <
𝐴) → ∃𝑦 ∈ ℕ ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦)) | 
| 34 |   | rexcom 2661 | 
. 2
⊢
(∃𝑥 ∈
ℕ ∃𝑦 ∈
ℕ 𝐴 = (𝑥 / 𝑦) ↔ ∃𝑦 ∈ ℕ ∃𝑥 ∈ ℕ 𝐴 = (𝑥 / 𝑦)) | 
| 35 | 33, 34 | sylibr 134 | 
1
⊢ ((𝐴 ∈ ℚ ∧ 0 <
𝐴) → ∃𝑥 ∈ ℕ ∃𝑦 ∈ ℕ 𝐴 = (𝑥 / 𝑦)) |