| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | disjel 4456 | . . . . . . . . . . 11
⊢ (((𝐴 ∩ 𝐵) = ∅ ∧ 𝑥 ∈ 𝐴) → ¬ 𝑥 ∈ 𝐵) | 
| 2 |  | eleq1w 2823 | . . . . . . . . . . . 12
⊢ (𝑥 = 𝑦 → (𝑥 ∈ 𝐵 ↔ 𝑦 ∈ 𝐵)) | 
| 3 | 2 | notbid 318 | . . . . . . . . . . 11
⊢ (𝑥 = 𝑦 → (¬ 𝑥 ∈ 𝐵 ↔ ¬ 𝑦 ∈ 𝐵)) | 
| 4 | 1, 3 | syl5ibcom 245 | . . . . . . . . . 10
⊢ (((𝐴 ∩ 𝐵) = ∅ ∧ 𝑥 ∈ 𝐴) → (𝑥 = 𝑦 → ¬ 𝑦 ∈ 𝐵)) | 
| 5 | 4 | con2d 134 | . . . . . . . . 9
⊢ (((𝐴 ∩ 𝐵) = ∅ ∧ 𝑥 ∈ 𝐴) → (𝑦 ∈ 𝐵 → ¬ 𝑥 = 𝑦)) | 
| 6 | 5 | impr 454 | . . . . . . . 8
⊢ (((𝐴 ∩ 𝐵) = ∅ ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)) → ¬ 𝑥 = 𝑦) | 
| 7 |  | biorf 936 | . . . . . . . 8
⊢ (¬
𝑥 = 𝑦 → ((𝐶 ∩ 𝐷) = ∅ ↔ (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 8 | 6, 7 | syl 17 | . . . . . . 7
⊢ (((𝐴 ∩ 𝐵) = ∅ ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)) → ((𝐶 ∩ 𝐷) = ∅ ↔ (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 9 | 8 | bicomd 223 | . . . . . 6
⊢ (((𝐴 ∩ 𝐵) = ∅ ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)) → ((𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ↔ (𝐶 ∩ 𝐷) = ∅)) | 
| 10 | 9 | 2ralbidva 3218 | . . . . 5
⊢ ((𝐴 ∩ 𝐵) = ∅ → (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅)) | 
| 11 | 10 | anbi2d 630 | . . . 4
⊢ ((𝐴 ∩ 𝐵) = ∅ → ((∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅)) ↔ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅))) | 
| 12 |  | ralunb 4196 | . . . . . 6
⊢
(∀𝑦 ∈
(𝐴 ∪ 𝐵)(𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ↔ (∀𝑦 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ∧ ∀𝑦 ∈ 𝐵 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 13 | 12 | ralbii 3092 | . . . . 5
⊢
(∀𝑥 ∈
𝐴 ∀𝑦 ∈ (𝐴 ∪ 𝐵)(𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ↔ ∀𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ∧ ∀𝑦 ∈ 𝐵 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 14 |  | nfv 1913 | . . . . . 6
⊢
Ⅎ𝑧∀𝑦 ∈ (𝐴 ∪ 𝐵)(𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) | 
| 15 |  | nfcv 2904 | . . . . . . 7
⊢
Ⅎ𝑥(𝐴 ∪ 𝐵) | 
| 16 |  | nfv 1913 | . . . . . . . 8
⊢
Ⅎ𝑥 𝑧 = 𝑤 | 
| 17 |  | nfcsb1v 3922 | . . . . . . . . . 10
⊢
Ⅎ𝑥⦋𝑧 / 𝑥⦌𝐶 | 
| 18 |  | nfcsb1v 3922 | . . . . . . . . . 10
⊢
Ⅎ𝑥⦋𝑤 / 𝑥⦌𝐶 | 
| 19 | 17, 18 | nfin 4223 | . . . . . . . . 9
⊢
Ⅎ𝑥(⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) | 
| 20 | 19 | nfeq1 2920 | . . . . . . . 8
⊢
Ⅎ𝑥(⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅ | 
| 21 | 16, 20 | nfor 1903 | . . . . . . 7
⊢
Ⅎ𝑥(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) | 
| 22 | 15, 21 | nfralw 3310 | . . . . . 6
⊢
Ⅎ𝑥∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) | 
| 23 |  | equequ2 2024 | . . . . . . . . 9
⊢ (𝑤 = 𝑦 → (𝑥 = 𝑤 ↔ 𝑥 = 𝑦)) | 
| 24 |  | nfcv 2904 | . . . . . . . . . . . 12
⊢
Ⅎ𝑥𝑦 | 
| 25 |  | nfcv 2904 | . . . . . . . . . . . 12
⊢
Ⅎ𝑥𝐷 | 
| 26 |  | disjxun.1 | . . . . . . . . . . . 12
⊢ (𝑥 = 𝑦 → 𝐶 = 𝐷) | 
| 27 | 24, 25, 26 | csbhypf 3926 | . . . . . . . . . . 11
⊢ (𝑤 = 𝑦 → ⦋𝑤 / 𝑥⦌𝐶 = 𝐷) | 
| 28 | 27 | ineq2d 4219 | . . . . . . . . . 10
⊢ (𝑤 = 𝑦 → (𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = (𝐶 ∩ 𝐷)) | 
| 29 | 28 | eqeq1d 2738 | . . . . . . . . 9
⊢ (𝑤 = 𝑦 → ((𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅ ↔ (𝐶 ∩ 𝐷) = ∅)) | 
| 30 | 23, 29 | orbi12d 918 | . . . . . . . 8
⊢ (𝑤 = 𝑦 → ((𝑥 = 𝑤 ∨ (𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 31 | 30 | cbvralvw 3236 | . . . . . . 7
⊢
(∀𝑤 ∈
(𝐴 ∪ 𝐵)(𝑥 = 𝑤 ∨ (𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ ∀𝑦 ∈ (𝐴 ∪ 𝐵)(𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅)) | 
| 32 |  | equequ1 2023 | . . . . . . . . 9
⊢ (𝑥 = 𝑧 → (𝑥 = 𝑤 ↔ 𝑧 = 𝑤)) | 
| 33 |  | csbeq1a 3912 | . . . . . . . . . . 11
⊢ (𝑥 = 𝑧 → 𝐶 = ⦋𝑧 / 𝑥⦌𝐶) | 
| 34 | 33 | ineq1d 4218 | . . . . . . . . . 10
⊢ (𝑥 = 𝑧 → (𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶)) | 
| 35 | 34 | eqeq1d 2738 | . . . . . . . . 9
⊢ (𝑥 = 𝑧 → ((𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅ ↔ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)) | 
| 36 | 32, 35 | orbi12d 918 | . . . . . . . 8
⊢ (𝑥 = 𝑧 → ((𝑥 = 𝑤 ∨ (𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 37 | 36 | ralbidv 3177 | . . . . . . 7
⊢ (𝑥 = 𝑧 → (∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑥 = 𝑤 ∨ (𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 38 | 31, 37 | bitr3id 285 | . . . . . 6
⊢ (𝑥 = 𝑧 → (∀𝑦 ∈ (𝐴 ∪ 𝐵)(𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ↔ ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 39 | 14, 22, 38 | cbvralw 3305 | . . . . 5
⊢
(∀𝑥 ∈
𝐴 ∀𝑦 ∈ (𝐴 ∪ 𝐵)(𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ↔ ∀𝑧 ∈ 𝐴 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)) | 
| 40 |  | r19.26 3110 | . . . . 5
⊢
(∀𝑥 ∈
𝐴 (∀𝑦 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ∧ ∀𝑦 ∈ 𝐵 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅)) ↔ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 41 | 13, 39, 40 | 3bitr3i 301 | . . . 4
⊢
(∀𝑧 ∈
𝐴 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 42 | 26 | disjor 5124 | . . . . 5
⊢
(Disj 𝑥
∈ 𝐴 𝐶 ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅)) | 
| 43 | 42 | anbi1i 624 | . . . 4
⊢
((Disj 𝑥
∈ 𝐴 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅) ↔ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅)) | 
| 44 | 11, 41, 43 | 3bitr4g 314 | . . 3
⊢ ((𝐴 ∩ 𝐵) = ∅ → (∀𝑧 ∈ 𝐴 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ (Disj 𝑥 ∈ 𝐴 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅))) | 
| 45 |  | nfv 1913 | . . . . . . . . . 10
⊢
Ⅎ𝑤(𝑧 = 𝑥 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = ∅) | 
| 46 |  | equequ2 2024 | . . . . . . . . . . 11
⊢ (𝑥 = 𝑤 → (𝑧 = 𝑥 ↔ 𝑧 = 𝑤)) | 
| 47 |  | csbeq1a 3912 | . . . . . . . . . . . . 13
⊢ (𝑥 = 𝑤 → 𝐶 = ⦋𝑤 / 𝑥⦌𝐶) | 
| 48 | 47 | ineq2d 4219 | . . . . . . . . . . . 12
⊢ (𝑥 = 𝑤 → (⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶)) | 
| 49 | 48 | eqeq1d 2738 | . . . . . . . . . . 11
⊢ (𝑥 = 𝑤 → ((⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = ∅ ↔ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)) | 
| 50 | 46, 49 | orbi12d 918 | . . . . . . . . . 10
⊢ (𝑥 = 𝑤 → ((𝑧 = 𝑥 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = ∅) ↔ (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 51 | 45, 21, 50 | cbvralw 3305 | . . . . . . . . 9
⊢
(∀𝑥 ∈
𝐴 (𝑧 = 𝑥 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = ∅) ↔ ∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)) | 
| 52 |  | equequ1 2023 | . . . . . . . . . . . 12
⊢ (𝑧 = 𝑦 → (𝑧 = 𝑥 ↔ 𝑦 = 𝑥)) | 
| 53 |  | equcom 2016 | . . . . . . . . . . . 12
⊢ (𝑦 = 𝑥 ↔ 𝑥 = 𝑦) | 
| 54 | 52, 53 | bitrdi 287 | . . . . . . . . . . 11
⊢ (𝑧 = 𝑦 → (𝑧 = 𝑥 ↔ 𝑥 = 𝑦)) | 
| 55 | 24, 25, 26 | csbhypf 3926 | . . . . . . . . . . . . . 14
⊢ (𝑧 = 𝑦 → ⦋𝑧 / 𝑥⦌𝐶 = 𝐷) | 
| 56 | 55 | ineq1d 4218 | . . . . . . . . . . . . 13
⊢ (𝑧 = 𝑦 → (⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = (𝐷 ∩ 𝐶)) | 
| 57 |  | incom 4208 | . . . . . . . . . . . . 13
⊢ (𝐷 ∩ 𝐶) = (𝐶 ∩ 𝐷) | 
| 58 | 56, 57 | eqtrdi 2792 | . . . . . . . . . . . 12
⊢ (𝑧 = 𝑦 → (⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = (𝐶 ∩ 𝐷)) | 
| 59 | 58 | eqeq1d 2738 | . . . . . . . . . . 11
⊢ (𝑧 = 𝑦 → ((⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = ∅ ↔ (𝐶 ∩ 𝐷) = ∅)) | 
| 60 | 54, 59 | orbi12d 918 | . . . . . . . . . 10
⊢ (𝑧 = 𝑦 → ((𝑧 = 𝑥 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = ∅) ↔ (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 61 | 60 | ralbidv 3177 | . . . . . . . . 9
⊢ (𝑧 = 𝑦 → (∀𝑥 ∈ 𝐴 (𝑧 = 𝑥 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ 𝐶) = ∅) ↔ ∀𝑥 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 62 | 51, 61 | bitr3id 285 | . . . . . . . 8
⊢ (𝑧 = 𝑦 → (∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ ∀𝑥 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅))) | 
| 63 | 62 | cbvralvw 3236 | . . . . . . 7
⊢
(∀𝑧 ∈
𝐵 ∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ ∀𝑦 ∈ 𝐵 ∀𝑥 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅)) | 
| 64 |  | ralcom 3288 | . . . . . . 7
⊢
(∀𝑦 ∈
𝐵 ∀𝑥 ∈ 𝐴 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅) ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅)) | 
| 65 | 63, 64 | bitri 275 | . . . . . 6
⊢
(∀𝑧 ∈
𝐵 ∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝑥 = 𝑦 ∨ (𝐶 ∩ 𝐷) = ∅)) | 
| 66 | 65, 10 | bitrid 283 | . . . . 5
⊢ ((𝐴 ∩ 𝐵) = ∅ → (∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅)) | 
| 67 | 66 | anbi1d 631 | . . . 4
⊢ ((𝐴 ∩ 𝐵) = ∅ → ((∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ∧ ∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐵 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)) ↔ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅ ∧ ∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐵 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)))) | 
| 68 |  | ralunb 4196 | . . . . . 6
⊢
(∀𝑤 ∈
(𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ (∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ∧ ∀𝑤 ∈ 𝐵 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 69 | 68 | ralbii 3092 | . . . . 5
⊢
(∀𝑧 ∈
𝐵 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ ∀𝑧 ∈ 𝐵 (∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ∧ ∀𝑤 ∈ 𝐵 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 70 |  | r19.26 3110 | . . . . 5
⊢
(∀𝑧 ∈
𝐵 (∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ∧ ∀𝑤 ∈ 𝐵 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)) ↔ (∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ∧ ∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐵 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 71 | 69, 70 | bitri 275 | . . . 4
⊢
(∀𝑧 ∈
𝐵 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ (∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐴 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ∧ ∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐵 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 72 |  | disjors 5125 | . . . . 5
⊢
(Disj 𝑥
∈ 𝐵 𝐶 ↔ ∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐵 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)) | 
| 73 | 72 | anbi2ci 625 | . . . 4
⊢
((Disj 𝑥
∈ 𝐵 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅) ↔ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅ ∧ ∀𝑧 ∈ 𝐵 ∀𝑤 ∈ 𝐵 (𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 74 | 67, 71, 73 | 3bitr4g 314 | . . 3
⊢ ((𝐴 ∩ 𝐵) = ∅ → (∀𝑧 ∈ 𝐵 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ (Disj 𝑥 ∈ 𝐵 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅))) | 
| 75 | 44, 74 | anbi12d 632 | . 2
⊢ ((𝐴 ∩ 𝐵) = ∅ → ((∀𝑧 ∈ 𝐴 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ∧ ∀𝑧 ∈ 𝐵 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)) ↔ ((Disj 𝑥 ∈ 𝐴 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅) ∧ (Disj 𝑥 ∈ 𝐵 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅)))) | 
| 76 |  | disjors 5125 | . . 3
⊢
(Disj 𝑥
∈ (𝐴 ∪ 𝐵)𝐶 ↔ ∀𝑧 ∈ (𝐴 ∪ 𝐵)∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅)) | 
| 77 |  | ralunb 4196 | . . 3
⊢
(∀𝑧 ∈
(𝐴 ∪ 𝐵)∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ↔ (∀𝑧 ∈ 𝐴 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ∧ ∀𝑧 ∈ 𝐵 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 78 | 76, 77 | bitri 275 | . 2
⊢
(Disj 𝑥
∈ (𝐴 ∪ 𝐵)𝐶 ↔ (∀𝑧 ∈ 𝐴 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅) ∧ ∀𝑧 ∈ 𝐵 ∀𝑤 ∈ (𝐴 ∪ 𝐵)(𝑧 = 𝑤 ∨ (⦋𝑧 / 𝑥⦌𝐶 ∩ ⦋𝑤 / 𝑥⦌𝐶) = ∅))) | 
| 79 |  | df-3an 1088 | . . 3
⊢
((Disj 𝑥
∈ 𝐴 𝐶 ∧ Disj 𝑥 ∈ 𝐵 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅) ↔ ((Disj 𝑥 ∈ 𝐴 𝐶 ∧ Disj 𝑥 ∈ 𝐵 𝐶) ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅)) | 
| 80 |  | anandir 677 | . . 3
⊢
(((Disj 𝑥
∈ 𝐴 𝐶 ∧ Disj 𝑥 ∈ 𝐵 𝐶) ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅) ↔ ((Disj 𝑥 ∈ 𝐴 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅) ∧ (Disj 𝑥 ∈ 𝐵 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅))) | 
| 81 | 79, 80 | bitri 275 | . 2
⊢
((Disj 𝑥
∈ 𝐴 𝐶 ∧ Disj 𝑥 ∈ 𝐵 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅) ↔ ((Disj 𝑥 ∈ 𝐴 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅) ∧ (Disj 𝑥 ∈ 𝐵 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅))) | 
| 82 | 75, 78, 81 | 3bitr4g 314 | 1
⊢ ((𝐴 ∩ 𝐵) = ∅ → (Disj 𝑥 ∈ (𝐴 ∪ 𝐵)𝐶 ↔ (Disj 𝑥 ∈ 𝐴 𝐶 ∧ Disj 𝑥 ∈ 𝐵 𝐶 ∧ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝐶 ∩ 𝐷) = ∅))) |