Proof of Theorem rankid
| Step | Hyp | Ref
| Expression |
| 1 | | rankid.1 |
. . . 4
⊢ A ∈
V |
| 2 | | rankwflem 4675 |
. . . 4
⊢ (A ∈ V
→ ∃x ∈ On A ∈
(R1 ‘suc x)) |
| 3 | 1, 2 | ax-mp 7 |
. . 3
⊢ ∃x ∈ On A ∈ (R1 ‘suc x) |
| 4 | | ax-17 973 |
. . . . 5
⊢ (y ∈ A → ∀x y ∈ A) |
| 5 | | ax-17 973 |
. . . . . 6
⊢ (y ∈
R1 → ∀x y ∈ R1) |
| 6 | | hbrab1 1775 |
. . . . . . . 8
⊢ (y ∈ {x ∈ On∣A ∈ (R1 ‘suc x)} → ∀x y ∈ {x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 7 | 6 | hbint 2547 |
. . . . . . 7
⊢ (y ∈ ∩{x ∈ On∣A ∈
(R1 ‘suc x)} →
∀x
y ∈ ∩{x ∈ On∣A ∈
(R1 ‘suc x)}) |
| 8 | 7 | hbsuc 3046 |
. . . . . 6
⊢ (y ∈ suc ∩{x ∈ On∣A ∈
(R1 ‘suc x)} →
∀x
y ∈ suc
∩{x ∈ On∣A ∈
(R1 ‘suc x)}) |
| 9 | 5, 8 | hbfv 3735 |
. . . . 5
⊢ (y ∈
(R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) → ∀x y ∈
(R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)})) |
| 10 | 4, 9 | hbel 1569 |
. . . 4
⊢ (A ∈
(R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) → ∀x A ∈
(R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)})) |
| 11 | | suceq 3040 |
. . . . . 6
⊢ (x = ∩{x ∈ On∣A ∈ (R1 ‘suc x)} → suc x
= suc ∩{x ∈ On∣A ∈
(R1 ‘suc x)}) |
| 12 | 11 | fveq2d 3734 |
. . . . 5
⊢ (x = ∩{x ∈ On∣A ∈ (R1 ‘suc x)} → (R1 ‘suc x) = (R1 ‘suc ∩{x ∈ On∣A ∈
(R1 ‘suc x)})) |
| 13 | 12 | eleq2d 1544 |
. . . 4
⊢ (x = ∩{x ∈ On∣A ∈ (R1 ‘suc x)} → (A
∈ (R1 ‘suc x) ↔ A
∈ (R1 ‘suc ∩{x ∈ On∣A ∈
(R1 ‘suc x)}))) |
| 14 | 10, 13 | onminsb 3015 |
. . 3
⊢ (∃x ∈ On A ∈ (R1 ‘suc x) → A
∈ (R1 ‘suc ∩{x ∈ On∣A ∈
(R1 ‘suc x)})) |
| 15 | 3, 14 | ax-mp 7 |
. 2
⊢ A ∈
(R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 16 | 1 | rankval 4678 |
. . . 4
⊢ (rank ‘A) = ∩{x ∈ On∣A ∈ (R1 ‘suc x)} |
| 17 | | suceq 3040 |
. . . 4
⊢ ((rank ‘A) = ∩{x ∈ On∣A ∈ (R1 ‘suc x)} → suc (rank ‘A) = suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 18 | 16, 17 | ax-mp 7 |
. . 3
⊢ suc (rank ‘A) = suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)} |
| 19 | 18 | fveq2i 3733 |
. 2
⊢ (R1
‘suc (rank ‘A)) =
(R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 20 | 15, 19 | eleqtrr 1550 |
1
⊢ A ∈
(R1 ‘suc (rank ‘A)) |