Proof of Theorem alephord
| Step | Hyp | Ref
| Expression |
| 1 | | alephordi 3679 |
. . 3
⊢ (B
∈ On → (A ∈ B → (ℵ ‘A) ≺ (ℵ ‘B))) |
| 2 | 1 | adantl 305 |
. 2
⊢ ((A
∈ On ∧ B ∈ On) →
(A ∈ B → (ℵ ‘A) ≺ (ℵ ‘B))) |
| 3 | | alephordi 3679 |
. . . . . . . . 9
⊢ (A
∈ On → (B ∈ A → (ℵ ‘B) ≺ (ℵ ‘A))) |
| 4 | 3 | con3d 87 |
. . . . . . . 8
⊢ (A
∈ On → (¬ (ℵ ‘B)
≺ (ℵ ‘A) → ¬
B ∈ A)) |
| 5 | | alephon 3671 |
. . . . . . . . 9
⊢ (ℵ ‘A) ∈ On |
| 6 | | alephon 3671 |
. . . . . . . . 9
⊢ (ℵ ‘B) ∈ On |
| 7 | | domtri 3644 |
. . . . . . . . 9
⊢ (((ℵ ‘A) ∈ On ∧ (ℵ ‘B) ∈ On) → ((ℵ ‘A) ≼ (ℵ ‘B) ↔ ¬ (ℵ ‘B) ≺ (ℵ ‘A))) |
| 8 | 5, 6, 7 | mp2an 520 |
. . . . . . . 8
⊢ ((ℵ ‘A) ≼ (ℵ ‘B) ↔ ¬ (ℵ ‘B) ≺ (ℵ ‘A)) |
| 9 | 4, 8 | syl5ib 181 |
. . . . . . 7
⊢ (A
∈ On → ((ℵ ‘A)
≼ (ℵ ‘B) → ¬
B ∈ A)) |
| 10 | 9 | adantr 306 |
. . . . . 6
⊢ ((A
∈ On ∧ B ∈ On) →
((ℵ ‘A) ≼ (ℵ
‘B) → ¬ B ∈ A)) |
| 11 | | ontri1 2232 |
. . . . . 6
⊢ ((A
∈ On ∧ B ∈ On) →
(A ⊆ B ↔ ¬ B
∈ A)) |
| 12 | 10, 11 | sylibrd 179 |
. . . . 5
⊢ ((A
∈ On ∧ B ∈ On) →
((ℵ ‘A) ≼ (ℵ
‘B) → A ⊆ B)) |
| 13 | | fveq2 2832 |
. . . . . . . 8
⊢ (A =
B → (ℵ ‘A) = (ℵ ‘B)) |
| 14 | | eqeng 3296 |
. . . . . . . . 9
⊢ ((ℵ ‘A) ∈ On → ((ℵ ‘A) = (ℵ ‘B) → (ℵ ‘A) ≈ (ℵ ‘B))) |
| 15 | 5, 14 | ax-mp 6 |
. . . . . . . 8
⊢ ((ℵ ‘A) = (ℵ ‘B) → (ℵ ‘A) ≈ (ℵ ‘B)) |
| 16 | 13, 15 | syl 12 |
. . . . . . 7
⊢ (A =
B → (ℵ ‘A) ≈ (ℵ ‘B)) |
| 17 | 16 | con3i 90 |
. . . . . 6
⊢ (¬ (ℵ ‘A) ≈ (ℵ ‘B) → ¬ A = B) |
| 18 | 17 | a1i 7 |
. . . . 5
⊢ ((A
∈ On ∧ B ∈ On) → (¬
(ℵ ‘A) ≈ (ℵ
‘B) → ¬ A = B)) |
| 19 | 12, 18 | anim12d 431 |
. . . 4
⊢ ((A
∈ On ∧ B ∈ On) →
(((ℵ ‘A) ≼ (ℵ
‘B) ∧ ¬ (ℵ
‘A) ≈ (ℵ ‘B)) → (A
⊆ B ∧ ¬ A = B))) |
| 20 | | onelpsst 2253 |
. . . 4
⊢ ((A
∈ On ∧ B ∈ On) →
(A ∈ B ↔ (A
⊆ B ∧ ¬ A = B))) |
| 21 | 19, 20 | sylibrd 179 |
. . 3
⊢ ((A
∈ On ∧ B ∈ On) →
(((ℵ ‘A) ≼ (ℵ
‘B) ∧ ¬ (ℵ
‘A) ≈ (ℵ ‘B)) → A
∈ B)) |
| 22 | | brsdom 3286 |
. . 3
⊢ ((ℵ ‘A) ≺ (ℵ ‘B) ↔ ((ℵ ‘A) ≼ (ℵ ‘B) ∧ ¬ (ℵ ‘A) ≈ (ℵ ‘B))) |
| 23 | 21, 22 | syl5ib 181 |
. 2
⊢ ((A
∈ On ∧ B ∈ On) →
((ℵ ‘A) ≺ (ℵ
‘B) → A ∈ B)) |
| 24 | 2, 23 | impbid 397 |
1
⊢ ((A
∈ On ∧ B ∈ On) →
(A ∈ B ↔ (ℵ ‘A) ≺ (ℵ ‘B))) |