Proof of Theorem rankid
| Step | Hyp | Ref
| Expression |
| 1 | | rankid.1 |
. . . 4
⊢ A
∈ V |
| 2 | | rankwflem 3509 |
. . . 4
⊢ (A
∈ V → ∃x ∈ On
A ∈ (R1 ‘suc
x)) |
| 3 | 1, 2 | ax-mp 6 |
. . 3
⊢ ∃x ∈ On A
∈ (R1 ‘suc x) |
| 4 | | ax-17 925 |
. . . . 5
⊢ (y
∈ A → ∀x y ∈
A) |
| 5 | | ax-17 925 |
. . . . . 6
⊢ (y
∈ R1 → ∀x y ∈
R1) |
| 6 | | hbrab1 1310 |
. . . . . . . 8
⊢ (y
∈ {x ∈ On∣A ∈ (R1 ‘suc x)} → ∀x y ∈
{x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 7 | 6 | hbint 1975 |
. . . . . . 7
⊢ (y
∈ ∩{x
∈ On∣A ∈
(R1 ‘suc x)} →
∀x y ∈ ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 8 | 7 | hbsuc 2294 |
. . . . . 6
⊢ (y
∈ suc ∩{x
∈ On∣A ∈
(R1 ‘suc x)} →
∀x y ∈ suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 9 | 5, 8 | hbfv 2837 |
. . . . 5
⊢ (y
∈ (R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) → ∀x y ∈
(R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)})) |
| 10 | 4, 9 | hbel 1172 |
. . . 4
⊢ (A
∈ (R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) → ∀x A ∈
(R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)})) |
| 11 | | suceq 2288 |
. . . . . 6
⊢ (x =
∩{x ∈
On∣A ∈ (R1
‘suc x)} → suc x = suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 12 | 11 | fveq2d 2836 |
. . . . 5
⊢ (x =
∩{x ∈
On∣A ∈ (R1
‘suc x)} → (R1
‘suc x) = (R1
‘suc ∩{x
∈ On∣A ∈
(R1 ‘suc x)})) |
| 13 | 12 | eleq2d 1156 |
. . . 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 2264 |
. . 3
⊢ (∃x ∈ On A
∈ (R1 ‘suc x)
→ A ∈ (R1
‘suc ∩{x
∈ On∣A ∈
(R1 ‘suc x)})) |
| 15 | 3, 14 | ax-mp 6 |
. 2
⊢ A
∈ (R1 ‘suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 16 | 1 | rankval 3512 |
. . . 4
⊢ (rank ‘A) = ∩{x ∈ On∣A ∈ (R1 ‘suc x)} |
| 17 | | suceq 2288 |
. . . 4
⊢ ((rank ‘A) = ∩{x ∈ On∣A ∈ (R1 ‘suc x)} → suc (rank ‘A) = suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)}) |
| 18 | 16, 17 | ax-mp 6 |
. . 3
⊢ suc (rank ‘A) = suc ∩{x ∈ On∣A ∈ (R1 ‘suc x)} |
| 19 | 18 | fveq2i 2835 |
. 2
⊢ (R1 ‘suc (rank
‘A)) = (R1
‘suc ∩{x
∈ On∣A ∈
(R1 ‘suc x)}) |
| 20 | 15, 19 | eleqtrr 1162 |
1
⊢ A
∈ (R1 ‘suc (rank ‘A)) |