| Step | Hyp | Ref
 | Expression | 
| 1 |   | 1zzd 9353 | 
. . 3
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → 1 ∈
ℤ) | 
| 2 |   | breq1 4036 | 
. . . 4
⊢ (𝑛 = 1 → (𝑛 ∥ 𝑋 ↔ 1 ∥ 𝑋)) | 
| 3 |   | breq1 4036 | 
. . . 4
⊢ (𝑛 = 1 → (𝑛 ∥ 𝑌 ↔ 1 ∥ 𝑌)) | 
| 4 | 2, 3 | anbi12d 473 | 
. . 3
⊢ (𝑛 = 1 → ((𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌) ↔ (1 ∥ 𝑋 ∧ 1 ∥ 𝑌))) | 
| 5 |   | 1dvds 11970 | 
. . . . 5
⊢ (𝑋 ∈ ℤ → 1 ∥
𝑋) | 
| 6 |   | 1dvds 11970 | 
. . . . 5
⊢ (𝑌 ∈ ℤ → 1 ∥
𝑌) | 
| 7 | 5, 6 | anim12i 338 | 
. . . 4
⊢ ((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) → (1
∥ 𝑋 ∧ 1 ∥
𝑌)) | 
| 8 | 7 | adantr 276 | 
. . 3
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → (1 ∥ 𝑋 ∧ 1 ∥ 𝑌)) | 
| 9 |   | elnnuz 9638 | 
. . . . . . 7
⊢ (𝑛 ∈ ℕ ↔ 𝑛 ∈
(ℤ≥‘1)) | 
| 10 | 9 | biimpri 133 | 
. . . . . 6
⊢ (𝑛 ∈
(ℤ≥‘1) → 𝑛 ∈ ℕ) | 
| 11 |   | simpll 527 | 
. . . . . 6
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ 𝑛 ∈
(ℤ≥‘1)) → 𝑋 ∈ ℤ) | 
| 12 |   | dvdsdc 11963 | 
. . . . . 6
⊢ ((𝑛 ∈ ℕ ∧ 𝑋 ∈ ℤ) →
DECID 𝑛
∥ 𝑋) | 
| 13 | 10, 11, 12 | syl2an2 594 | 
. . . . 5
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ 𝑛 ∈
(ℤ≥‘1)) → DECID 𝑛 ∥ 𝑋) | 
| 14 |   | simplr 528 | 
. . . . . 6
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ 𝑛 ∈
(ℤ≥‘1)) → 𝑌 ∈ ℤ) | 
| 15 |   | dvdsdc 11963 | 
. . . . . 6
⊢ ((𝑛 ∈ ℕ ∧ 𝑌 ∈ ℤ) →
DECID 𝑛
∥ 𝑌) | 
| 16 | 10, 14, 15 | syl2an2 594 | 
. . . . 5
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ 𝑛 ∈
(ℤ≥‘1)) → DECID 𝑛 ∥ 𝑌) | 
| 17 | 13, 16 | dcand 934 | 
. . . 4
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ 𝑛 ∈
(ℤ≥‘1)) → DECID (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 18 | 17 | adantlr 477 | 
. . 3
⊢ ((((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) ∧ 𝑛 ∈ (ℤ≥‘1))
→ DECID (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 19 |   | dvdsbnd 12123 | 
. . . . . . 7
⊢ ((𝑋 ∈ ℤ ∧ 𝑋 ≠ 0) → ∃𝑗 ∈ ℕ ∀𝑛 ∈
(ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑋) | 
| 20 |   | nnuz 9637 | 
. . . . . . . 8
⊢ ℕ =
(ℤ≥‘1) | 
| 21 | 20 | rexeqi 2698 | 
. . . . . . 7
⊢
(∃𝑗 ∈
ℕ ∀𝑛 ∈
(ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑋 ↔ ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑋) | 
| 22 | 19, 21 | sylib 122 | 
. . . . . 6
⊢ ((𝑋 ∈ ℤ ∧ 𝑋 ≠ 0) → ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑋) | 
| 23 |   | id 19 | 
. . . . . . . . 9
⊢ (¬
𝑛 ∥ 𝑋 → ¬ 𝑛 ∥ 𝑋) | 
| 24 | 23 | intnanrd 933 | 
. . . . . . . 8
⊢ (¬
𝑛 ∥ 𝑋 → ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 25 | 24 | ralimi 2560 | 
. . . . . . 7
⊢
(∀𝑛 ∈
(ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑋 → ∀𝑛 ∈ (ℤ≥‘𝑗) ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 26 | 25 | reximi 2594 | 
. . . . . 6
⊢
(∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑋 → ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 27 | 22, 26 | syl 14 | 
. . . . 5
⊢ ((𝑋 ∈ ℤ ∧ 𝑋 ≠ 0) → ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 28 | 27 | ad4ant14 514 | 
. . . 4
⊢ ((((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) ∧ 𝑋 ≠ 0) → ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 29 |   | dvdsbnd 12123 | 
. . . . . . 7
⊢ ((𝑌 ∈ ℤ ∧ 𝑌 ≠ 0) → ∃𝑗 ∈ ℕ ∀𝑛 ∈
(ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑌) | 
| 30 | 20 | rexeqi 2698 | 
. . . . . . 7
⊢
(∃𝑗 ∈
ℕ ∀𝑛 ∈
(ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑌 ↔ ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑌) | 
| 31 | 29, 30 | sylib 122 | 
. . . . . 6
⊢ ((𝑌 ∈ ℤ ∧ 𝑌 ≠ 0) → ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑌) | 
| 32 |   | id 19 | 
. . . . . . . . 9
⊢ (¬
𝑛 ∥ 𝑌 → ¬ 𝑛 ∥ 𝑌) | 
| 33 | 32 | intnand 932 | 
. . . . . . . 8
⊢ (¬
𝑛 ∥ 𝑌 → ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 34 | 33 | ralimi 2560 | 
. . . . . . 7
⊢
(∀𝑛 ∈
(ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑌 → ∀𝑛 ∈ (ℤ≥‘𝑗) ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 35 | 34 | reximi 2594 | 
. . . . . 6
⊢
(∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ 𝑛 ∥ 𝑌 → ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 36 | 31, 35 | syl 14 | 
. . . . 5
⊢ ((𝑌 ∈ ℤ ∧ 𝑌 ≠ 0) → ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 37 | 36 | ad4ant24 516 | 
. . . 4
⊢ ((((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) ∧ 𝑌 ≠ 0) → ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 38 |   | simpr 110 | 
. . . . . 6
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → ¬ (𝑋 = 0 ∧ 𝑌 = 0)) | 
| 39 |   | simpll 527 | 
. . . . . . . 8
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → 𝑋 ∈ ℤ) | 
| 40 |   | 0z 9337 | 
. . . . . . . 8
⊢ 0 ∈
ℤ | 
| 41 |   | zdceq 9401 | 
. . . . . . . 8
⊢ ((𝑋 ∈ ℤ ∧ 0 ∈
ℤ) → DECID 𝑋 = 0) | 
| 42 | 39, 40, 41 | sylancl 413 | 
. . . . . . 7
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) →
DECID 𝑋 =
0) | 
| 43 |   | ianordc 900 | 
. . . . . . 7
⊢
(DECID 𝑋 = 0 → (¬ (𝑋 = 0 ∧ 𝑌 = 0) ↔ (¬ 𝑋 = 0 ∨ ¬ 𝑌 = 0))) | 
| 44 | 42, 43 | syl 14 | 
. . . . . 6
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → (¬ (𝑋 = 0 ∧ 𝑌 = 0) ↔ (¬ 𝑋 = 0 ∨ ¬ 𝑌 = 0))) | 
| 45 | 38, 44 | mpbid 147 | 
. . . . 5
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → (¬ 𝑋 = 0 ∨ ¬ 𝑌 = 0)) | 
| 46 |   | df-ne 2368 | 
. . . . . 6
⊢ (𝑋 ≠ 0 ↔ ¬ 𝑋 = 0) | 
| 47 |   | df-ne 2368 | 
. . . . . 6
⊢ (𝑌 ≠ 0 ↔ ¬ 𝑌 = 0) | 
| 48 | 46, 47 | orbi12i 765 | 
. . . . 5
⊢ ((𝑋 ≠ 0 ∨ 𝑌 ≠ 0) ↔ (¬ 𝑋 = 0 ∨ ¬ 𝑌 = 0)) | 
| 49 | 45, 48 | sylibr 134 | 
. . . 4
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → (𝑋 ≠ 0 ∨ 𝑌 ≠ 0)) | 
| 50 | 28, 37, 49 | mpjaodan 799 | 
. . 3
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → ∃𝑗 ∈
(ℤ≥‘1)∀𝑛 ∈ (ℤ≥‘𝑗) ¬ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)) | 
| 51 | 1, 4, 8, 18, 50 | zsupcl 10321 | 
. 2
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)}, ℝ, < ) ∈
(ℤ≥‘1)) | 
| 52 | 51, 20 | eleqtrrdi 2290 | 
1
⊢ (((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) ∧ ¬
(𝑋 = 0 ∧ 𝑌 = 0)) → sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑋 ∧ 𝑛 ∥ 𝑌)}, ℝ, < ) ∈
ℕ) |