| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | tru 1544 | . . . 4
⊢
⊤ | 
| 2 |  | eqeq12 2754 | . . . . . 6
⊢ ((𝑎 = 𝑥 ∧ 𝑏 = 𝑦) → (𝑎 = 𝑏 ↔ 𝑥 = 𝑦)) | 
| 3 |  | csbeq1 3902 | . . . . . . . 8
⊢ (𝑎 = 𝑥 → ⦋𝑎 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) = ⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) | 
| 4 |  | csbeq1 3902 | . . . . . . . 8
⊢ (𝑏 = 𝑦 → ⦋𝑏 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) = ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) | 
| 5 | 3, 4 | ineqan12d 4222 | . . . . . . 7
⊢ ((𝑎 = 𝑥 ∧ 𝑏 = 𝑦) → (⦋𝑎 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑏 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵))) | 
| 6 | 5 | eqeq1d 2739 | . . . . . 6
⊢ ((𝑎 = 𝑥 ∧ 𝑏 = 𝑦) → ((⦋𝑎 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑏 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅ ↔ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 7 | 2, 6 | orbi12d 919 | . . . . 5
⊢ ((𝑎 = 𝑥 ∧ 𝑏 = 𝑦) → ((𝑎 = 𝑏 ∨ (⦋𝑎 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑏 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅) ↔ (𝑥 = 𝑦 ∨ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅))) | 
| 8 |  | eqeq12 2754 | . . . . . . 7
⊢ ((𝑎 = 𝑦 ∧ 𝑏 = 𝑥) → (𝑎 = 𝑏 ↔ 𝑦 = 𝑥)) | 
| 9 |  | equcom 2017 | . . . . . . 7
⊢ (𝑦 = 𝑥 ↔ 𝑥 = 𝑦) | 
| 10 | 8, 9 | bitrdi 287 | . . . . . 6
⊢ ((𝑎 = 𝑦 ∧ 𝑏 = 𝑥) → (𝑎 = 𝑏 ↔ 𝑥 = 𝑦)) | 
| 11 |  | csbeq1 3902 | . . . . . . . . 9
⊢ (𝑎 = 𝑦 → ⦋𝑎 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) = ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) | 
| 12 |  | csbeq1 3902 | . . . . . . . . 9
⊢ (𝑏 = 𝑥 → ⦋𝑏 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) = ⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) | 
| 13 | 11, 12 | ineqan12d 4222 | . . . . . . . 8
⊢ ((𝑎 = 𝑦 ∧ 𝑏 = 𝑥) → (⦋𝑎 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑏 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = (⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵))) | 
| 14 |  | incom 4209 | . . . . . . . 8
⊢
(⦋𝑦 /
𝑛⦌(𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) | 
| 15 | 13, 14 | eqtrdi 2793 | . . . . . . 7
⊢ ((𝑎 = 𝑦 ∧ 𝑏 = 𝑥) → (⦋𝑎 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑏 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵))) | 
| 16 | 15 | eqeq1d 2739 | . . . . . 6
⊢ ((𝑎 = 𝑦 ∧ 𝑏 = 𝑥) → ((⦋𝑎 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑏 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅ ↔ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 17 | 10, 16 | orbi12d 919 | . . . . 5
⊢ ((𝑎 = 𝑦 ∧ 𝑏 = 𝑥) → ((𝑎 = 𝑏 ∨ (⦋𝑎 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑏 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅) ↔ (𝑥 = 𝑦 ∨ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅))) | 
| 18 |  | nnssre 12270 | . . . . . 6
⊢ ℕ
⊆ ℝ | 
| 19 | 18 | a1i 11 | . . . . 5
⊢ (⊤
→ ℕ ⊆ ℝ) | 
| 20 |  | biidd 262 | . . . . 5
⊢
((⊤ ∧ (𝑥
∈ ℕ ∧ 𝑦
∈ ℕ)) → ((𝑥
= 𝑦 ∨
(⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅) ↔ (𝑥 = 𝑦 ∨ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅))) | 
| 21 |  | nesym 2997 | . . . . . . . 8
⊢ (𝑦 ≠ 𝑥 ↔ ¬ 𝑥 = 𝑦) | 
| 22 |  | nnre 12273 | . . . . . . . . . 10
⊢ (𝑥 ∈ ℕ → 𝑥 ∈
ℝ) | 
| 23 |  | nnre 12273 | . . . . . . . . . 10
⊢ (𝑦 ∈ ℕ → 𝑦 ∈
ℝ) | 
| 24 |  | id 22 | . . . . . . . . . 10
⊢ (𝑥 ≤ 𝑦 → 𝑥 ≤ 𝑦) | 
| 25 |  | leltne 11350 | . . . . . . . . . 10
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ ∧ 𝑥 ≤ 𝑦) → (𝑥 < 𝑦 ↔ 𝑦 ≠ 𝑥)) | 
| 26 | 22, 23, 24, 25 | syl3an 1161 | . . . . . . . . 9
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 ≤ 𝑦) → (𝑥 < 𝑦 ↔ 𝑦 ≠ 𝑥)) | 
| 27 |  | vex 3484 | . . . . . . . . . . . . . . 15
⊢ 𝑥 ∈ V | 
| 28 |  | nfcsb1v 3923 | . . . . . . . . . . . . . . . 16
⊢
Ⅎ𝑛⦋𝑥 / 𝑛⦌𝐴 | 
| 29 |  | nfcv 2905 | . . . . . . . . . . . . . . . . 17
⊢
Ⅎ𝑛(1..^𝑥) | 
| 30 |  | iundisjf.2 | . . . . . . . . . . . . . . . . 17
⊢
Ⅎ𝑛𝐵 | 
| 31 | 29, 30 | nfiun 5023 | . . . . . . . . . . . . . . . 16
⊢
Ⅎ𝑛∪ 𝑘 ∈ (1..^𝑥)𝐵 | 
| 32 | 28, 31 | nfdif 4129 | . . . . . . . . . . . . . . 15
⊢
Ⅎ𝑛(⦋𝑥 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑥)𝐵) | 
| 33 |  | csbeq1a 3913 | . . . . . . . . . . . . . . . 16
⊢ (𝑛 = 𝑥 → 𝐴 = ⦋𝑥 / 𝑛⦌𝐴) | 
| 34 |  | oveq2 7439 | . . . . . . . . . . . . . . . . 17
⊢ (𝑛 = 𝑥 → (1..^𝑛) = (1..^𝑥)) | 
| 35 | 34 | iuneq1d 5019 | . . . . . . . . . . . . . . . 16
⊢ (𝑛 = 𝑥 → ∪
𝑘 ∈ (1..^𝑛)𝐵 = ∪ 𝑘 ∈ (1..^𝑥)𝐵) | 
| 36 | 33, 35 | difeq12d 4127 | . . . . . . . . . . . . . . 15
⊢ (𝑛 = 𝑥 → (𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) = (⦋𝑥 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑥)𝐵)) | 
| 37 | 27, 32, 36 | csbief 3933 | . . . . . . . . . . . . . 14
⊢
⦋𝑥 /
𝑛⦌(𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) = (⦋𝑥 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑥)𝐵) | 
| 38 |  | vex 3484 | . . . . . . . . . . . . . . 15
⊢ 𝑦 ∈ V | 
| 39 |  | nfcsb1v 3923 | . . . . . . . . . . . . . . . 16
⊢
Ⅎ𝑛⦋𝑦 / 𝑛⦌𝐴 | 
| 40 |  | nfcv 2905 | . . . . . . . . . . . . . . . . 17
⊢
Ⅎ𝑛(1..^𝑦) | 
| 41 | 40, 30 | nfiun 5023 | . . . . . . . . . . . . . . . 16
⊢
Ⅎ𝑛∪ 𝑘 ∈ (1..^𝑦)𝐵 | 
| 42 | 39, 41 | nfdif 4129 | . . . . . . . . . . . . . . 15
⊢
Ⅎ𝑛(⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵) | 
| 43 |  | csbeq1a 3913 | . . . . . . . . . . . . . . . 16
⊢ (𝑛 = 𝑦 → 𝐴 = ⦋𝑦 / 𝑛⦌𝐴) | 
| 44 |  | oveq2 7439 | . . . . . . . . . . . . . . . . 17
⊢ (𝑛 = 𝑦 → (1..^𝑛) = (1..^𝑦)) | 
| 45 | 44 | iuneq1d 5019 | . . . . . . . . . . . . . . . 16
⊢ (𝑛 = 𝑦 → ∪
𝑘 ∈ (1..^𝑛)𝐵 = ∪ 𝑘 ∈ (1..^𝑦)𝐵) | 
| 46 | 43, 45 | difeq12d 4127 | . . . . . . . . . . . . . . 15
⊢ (𝑛 = 𝑦 → (𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) = (⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵)) | 
| 47 | 38, 42, 46 | csbief 3933 | . . . . . . . . . . . . . 14
⊢
⦋𝑦 /
𝑛⦌(𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) = (⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵) | 
| 48 | 37, 47 | ineq12i 4218 | . . . . . . . . . . . . 13
⊢
(⦋𝑥 /
𝑛⦌(𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ((⦋𝑥 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑥)𝐵) ∩ (⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵)) | 
| 49 |  | simp1 1137 | . . . . . . . . . . . . . . . . . 18
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → 𝑥 ∈ ℕ) | 
| 50 |  | nnuz 12921 | . . . . . . . . . . . . . . . . . 18
⊢ ℕ =
(ℤ≥‘1) | 
| 51 | 49, 50 | eleqtrdi 2851 | . . . . . . . . . . . . . . . . 17
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → 𝑥 ∈
(ℤ≥‘1)) | 
| 52 |  | simp2 1138 | . . . . . . . . . . . . . . . . . 18
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → 𝑦 ∈ ℕ) | 
| 53 | 52 | nnzd 12640 | . . . . . . . . . . . . . . . . 17
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → 𝑦 ∈ ℤ) | 
| 54 |  | simp3 1139 | . . . . . . . . . . . . . . . . 17
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → 𝑥 < 𝑦) | 
| 55 |  | elfzo2 13702 | . . . . . . . . . . . . . . . . 17
⊢ (𝑥 ∈ (1..^𝑦) ↔ (𝑥 ∈ (ℤ≥‘1)
∧ 𝑦 ∈ ℤ
∧ 𝑥 < 𝑦)) | 
| 56 | 51, 53, 54, 55 | syl3anbrc 1344 | . . . . . . . . . . . . . . . 16
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → 𝑥 ∈ (1..^𝑦)) | 
| 57 |  | nfcv 2905 | . . . . . . . . . . . . . . . . 17
⊢
Ⅎ𝑘(1..^𝑦) | 
| 58 |  | nfcv 2905 | . . . . . . . . . . . . . . . . 17
⊢
Ⅎ𝑘𝑥 | 
| 59 |  | iundisjf.1 | . . . . . . . . . . . . . . . . . 18
⊢
Ⅎ𝑘𝐴 | 
| 60 | 58, 59 | nfcsbw 3925 | . . . . . . . . . . . . . . . . 17
⊢
Ⅎ𝑘⦋𝑥 / 𝑛⦌𝐴 | 
| 61 |  | nfcv 2905 | . . . . . . . . . . . . . . . . . . . 20
⊢
Ⅎ𝑛𝑘 | 
| 62 |  | iundisjf.3 | . . . . . . . . . . . . . . . . . . . 20
⊢ (𝑛 = 𝑘 → 𝐴 = 𝐵) | 
| 63 | 61, 30, 62 | csbhypf 3927 | . . . . . . . . . . . . . . . . . . 19
⊢ (𝑥 = 𝑘 → ⦋𝑥 / 𝑛⦌𝐴 = 𝐵) | 
| 64 | 63 | equcoms 2019 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑘 = 𝑥 → ⦋𝑥 / 𝑛⦌𝐴 = 𝐵) | 
| 65 | 64 | eqcomd 2743 | . . . . . . . . . . . . . . . . 17
⊢ (𝑘 = 𝑥 → 𝐵 = ⦋𝑥 / 𝑛⦌𝐴) | 
| 66 | 57, 58, 60, 65 | ssiun2sf 32572 | . . . . . . . . . . . . . . . 16
⊢ (𝑥 ∈ (1..^𝑦) → ⦋𝑥 / 𝑛⦌𝐴 ⊆ ∪
𝑘 ∈ (1..^𝑦)𝐵) | 
| 67 | 56, 66 | syl 17 | . . . . . . . . . . . . . . 15
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → ⦋𝑥 / 𝑛⦌𝐴 ⊆ ∪
𝑘 ∈ (1..^𝑦)𝐵) | 
| 68 | 67 | ssdifssd 4147 | . . . . . . . . . . . . . 14
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → (⦋𝑥 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑥)𝐵) ⊆ ∪ 𝑘 ∈ (1..^𝑦)𝐵) | 
| 69 | 68 | ssrind 4244 | . . . . . . . . . . . . 13
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → ((⦋𝑥 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑥)𝐵) ∩ (⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵)) ⊆ (∪ 𝑘 ∈ (1..^𝑦)𝐵 ∩ (⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵))) | 
| 70 | 48, 69 | eqsstrid 4022 | . . . . . . . . . . . 12
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) ⊆ (∪ 𝑘 ∈ (1..^𝑦)𝐵 ∩ (⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵))) | 
| 71 |  | disjdif 4472 | . . . . . . . . . . . 12
⊢ (∪ 𝑘 ∈ (1..^𝑦)𝐵 ∩ (⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵)) = ∅ | 
| 72 |  | sseq0 4403 | . . . . . . . . . . . 12
⊢
(((⦋𝑥
/ 𝑛⦌(𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) ⊆ (∪ 𝑘 ∈ (1..^𝑦)𝐵 ∩ (⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵)) ∧ (∪ 𝑘 ∈ (1..^𝑦)𝐵 ∩ (⦋𝑦 / 𝑛⦌𝐴 ∖ ∪
𝑘 ∈ (1..^𝑦)𝐵)) = ∅) → (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅) | 
| 73 | 70, 71, 72 | sylancl 586 | . . . . . . . . . . 11
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 < 𝑦) → (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅) | 
| 74 | 73 | 3expia 1122 | . . . . . . . . . 10
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ) → (𝑥 < 𝑦 → (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 75 | 74 | 3adant3 1133 | . . . . . . . . 9
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 ≤ 𝑦) → (𝑥 < 𝑦 → (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 76 | 26, 75 | sylbird 260 | . . . . . . . 8
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 ≤ 𝑦) → (𝑦 ≠ 𝑥 → (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 77 | 21, 76 | biimtrrid 243 | . . . . . . 7
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 ≤ 𝑦) → (¬ 𝑥 = 𝑦 → (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 78 | 77 | orrd 864 | . . . . . 6
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ ∧ 𝑥 ≤ 𝑦) → (𝑥 = 𝑦 ∨ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 79 | 78 | adantl 481 | . . . . 5
⊢
((⊤ ∧ (𝑥
∈ ℕ ∧ 𝑦
∈ ℕ ∧ 𝑥 ≤
𝑦)) → (𝑥 = 𝑦 ∨ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 80 | 7, 17, 19, 20, 79 | wlogle 11796 | . . . 4
⊢
((⊤ ∧ (𝑥
∈ ℕ ∧ 𝑦
∈ ℕ)) → (𝑥
= 𝑦 ∨
(⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 81 | 1, 80 | mpan 690 | . . 3
⊢ ((𝑥 ∈ ℕ ∧ 𝑦 ∈ ℕ) → (𝑥 = 𝑦 ∨ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 82 | 81 | rgen2 3199 | . 2
⊢
∀𝑥 ∈
ℕ ∀𝑦 ∈
ℕ (𝑥 = 𝑦 ∨ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅) | 
| 83 |  | disjors 5126 | . 2
⊢
(Disj 𝑛
∈ ℕ (𝐴 ∖
∪ 𝑘 ∈ (1..^𝑛)𝐵) ↔ ∀𝑥 ∈ ℕ ∀𝑦 ∈ ℕ (𝑥 = 𝑦 ∨ (⦋𝑥 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵) ∩ ⦋𝑦 / 𝑛⦌(𝐴 ∖ ∪
𝑘 ∈ (1..^𝑛)𝐵)) = ∅)) | 
| 84 | 82, 83 | mpbir 231 | 1
⊢
Disj 𝑛 ∈
ℕ (𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) |