Step | Hyp | Ref
| Expression |
1 | | idn1 42194 |
. . . . . 6
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) ▶ (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) ) |
2 | | simpr 485 |
. . . . . 6
⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → 𝑎 ≠ ∅) |
3 | 1, 2 | e1a 42247 |
. . . . 5
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) ▶ 𝑎 ≠ ∅ ) |
4 | | exmid 892 |
. . . . . . . . . 10
⊢ ((𝑎 ∩ 𝑥) = ∅ ∨ ¬ (𝑎 ∩ 𝑥) = ∅) |
5 | | onfrALTlem1VD 42510 |
. . . . . . . . . . 11
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) , (𝑥 ∈ 𝑎 ∧ (𝑎 ∩ 𝑥) = ∅) ▶ ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅ ) |
6 | 5 | in2an 42228 |
. . . . . . . . . 10
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) , 𝑥 ∈ 𝑎 ▶ ((𝑎 ∩ 𝑥) = ∅ → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) ) |
7 | | onfrALTlem2VD 42509 |
. . . . . . . . . . 11
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) , (𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) ▶ ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅ ) |
8 | 7 | in2an 42228 |
. . . . . . . . . 10
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) , 𝑥 ∈ 𝑎 ▶ (¬
(𝑎 ∩ 𝑥) = ∅ → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) ) |
9 | | pm2.61 191 |
. . . . . . . . . . 11
⊢ (((𝑎 ∩ 𝑥) = ∅ → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) → ((¬ (𝑎 ∩ 𝑥) = ∅ → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅)) |
10 | 9 | a1i 11 |
. . . . . . . . . 10
⊢ (((𝑎 ∩ 𝑥) = ∅ ∨ ¬ (𝑎 ∩ 𝑥) = ∅) → (((𝑎 ∩ 𝑥) = ∅ → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) → ((¬ (𝑎 ∩ 𝑥) = ∅ → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅))) |
11 | 4, 6, 8, 10 | e022 42261 |
. . . . . . . . 9
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) , 𝑥 ∈ 𝑎 ▶ ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅ ) |
12 | 11 | in2 42225 |
. . . . . . . 8
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) ▶ (𝑥 ∈ 𝑎 → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) ) |
13 | 12 | gen11 42236 |
. . . . . . 7
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) ▶ ∀𝑥(𝑥 ∈ 𝑎 → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) ) |
14 | | 19.23v 1945 |
. . . . . . . 8
⊢
(∀𝑥(𝑥 ∈ 𝑎 → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) ↔ (∃𝑥 𝑥 ∈ 𝑎 → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅)) |
15 | 14 | biimpi 215 |
. . . . . . 7
⊢
(∀𝑥(𝑥 ∈ 𝑎 → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) → (∃𝑥 𝑥 ∈ 𝑎 → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅)) |
16 | 13, 15 | e1a 42247 |
. . . . . 6
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) ▶ (∃𝑥 𝑥 ∈ 𝑎 → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) ) |
17 | | n0 4280 |
. . . . . 6
⊢ (𝑎 ≠ ∅ ↔
∃𝑥 𝑥 ∈ 𝑎) |
18 | | imbi1 348 |
. . . . . . 7
⊢ ((𝑎 ≠ ∅ ↔
∃𝑥 𝑥 ∈ 𝑎) → ((𝑎 ≠ ∅ → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) ↔ (∃𝑥 𝑥 ∈ 𝑎 → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅))) |
19 | 18 | biimprcd 249 |
. . . . . 6
⊢
((∃𝑥 𝑥 ∈ 𝑎 → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) → ((𝑎 ≠ ∅ ↔ ∃𝑥 𝑥 ∈ 𝑎) → (𝑎 ≠ ∅ → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅))) |
20 | 16, 17, 19 | e10 42314 |
. . . . 5
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) ▶ (𝑎 ≠ ∅ →
∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) ) |
21 | | pm2.27 42 |
. . . . 5
⊢ (𝑎 ≠ ∅ → ((𝑎 ≠ ∅ →
∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) → ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅)) |
22 | 3, 20, 21 | e11 42308 |
. . . 4
⊢ ( (𝑎 ⊆ On ∧ 𝑎 ≠ ∅) ▶ ∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅ ) |
23 | 22 | in1 42191 |
. . 3
⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) →
∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) |
24 | 23 | ax-gen 1798 |
. 2
⊢
∀𝑎((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) →
∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) |
25 | | dfepfr 5574 |
. . 3
⊢ ( E Fr On
↔ ∀𝑎((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) →
∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅)) |
26 | 25 | biimpri 227 |
. 2
⊢
(∀𝑎((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) →
∃𝑦 ∈ 𝑎 (𝑎 ∩ 𝑦) = ∅) → E Fr On) |
27 | 24, 26 | e0a 42392 |
1
⊢ E Fr
On |