Proof of Theorem csbiebt
Step | Hyp | Ref
| Expression |
1 | | elex 2868 |
. 2
⊢ (A ∈ V → A ∈ V) |
2 | | spsbc 3059 |
. . . . 5
⊢ (A ∈ V →
(∀x(x = A → B =
C) → [̣A / x]̣(x =
A → B = C))) |
3 | 2 | adantr 451 |
. . . 4
⊢ ((A ∈ V ∧ ℲxC) →
(∀x(x = A → B =
C) → [̣A / x]̣(x =
A → B = C))) |
4 | | simpl 443 |
. . . . 5
⊢ ((A ∈ V ∧ ℲxC) →
A ∈
V) |
5 | | biimt 325 |
. . . . . . 7
⊢ (x = A →
(B = C
↔ (x = A → B =
C))) |
6 | | csbeq1a 3145 |
. . . . . . . 8
⊢ (x = A →
B = [A / x]B) |
7 | 6 | eqeq1d 2361 |
. . . . . . 7
⊢ (x = A →
(B = C
↔ [A / x]B =
C)) |
8 | 5, 7 | bitr3d 246 |
. . . . . 6
⊢ (x = A →
((x = A
→ B = C) ↔ [A / x]B =
C)) |
9 | 8 | adantl 452 |
. . . . 5
⊢ (((A ∈ V ∧ ℲxC) ∧ x = A) → ((x =
A → B = C) ↔
[A / x]B =
C)) |
10 | | nfv 1619 |
. . . . . 6
⊢ Ⅎx A ∈ V |
11 | | nfnfc1 2493 |
. . . . . 6
⊢ ℲxℲxC |
12 | 10, 11 | nfan 1824 |
. . . . 5
⊢ Ⅎx(A ∈ V ∧
ℲxC) |
13 | | nfcsb1v 3169 |
. . . . . . 7
⊢
Ⅎx[A / x]B |
14 | 13 | a1i 10 |
. . . . . 6
⊢ ((A ∈ V ∧ ℲxC) →
Ⅎx[A / x]B) |
15 | | simpr 447 |
. . . . . 6
⊢ ((A ∈ V ∧ ℲxC) →
ℲxC) |
16 | 14, 15 | nfeqd 2504 |
. . . . 5
⊢ ((A ∈ V ∧ ℲxC) →
Ⅎx[A / x]B =
C) |
17 | 4, 9, 12, 16 | sbciedf 3082 |
. . . 4
⊢ ((A ∈ V ∧ ℲxC) →
([̣A / x]̣(x =
A → B = C) ↔
[A / x]B =
C)) |
18 | 3, 17 | sylibd 205 |
. . 3
⊢ ((A ∈ V ∧ ℲxC) →
(∀x(x = A → B =
C) → [A / x]B =
C)) |
19 | 13 | a1i 10 |
. . . . . . . 8
⊢
(ℲxC → Ⅎx[A /
x]B) |
20 | | id 19 |
. . . . . . . 8
⊢
(ℲxC → ℲxC) |
21 | 19, 20 | nfeqd 2504 |
. . . . . . 7
⊢
(ℲxC → Ⅎx[A /
x]B = C) |
22 | 11, 21 | nfan1 1881 |
. . . . . 6
⊢ Ⅎx(ℲxC ∧ [A /
x]B = C) |
23 | 7 | biimprcd 216 |
. . . . . . 7
⊢ ([A / x]B =
C → (x = A →
B = C)) |
24 | 23 | adantl 452 |
. . . . . 6
⊢
((ℲxC ∧
[A / x]B =
C) → (x = A →
B = C)) |
25 | 22, 24 | alrimi 1765 |
. . . . 5
⊢
((ℲxC ∧
[A / x]B =
C) → ∀x(x = A →
B = C)) |
26 | 25 | ex 423 |
. . . 4
⊢
(ℲxC → ([A / x]B =
C → ∀x(x = A →
B = C))) |
27 | 26 | adantl 452 |
. . 3
⊢ ((A ∈ V ∧ ℲxC) →
([A / x]B =
C → ∀x(x = A →
B = C))) |
28 | 18, 27 | impbid 183 |
. 2
⊢ ((A ∈ V ∧ ℲxC) →
(∀x(x = A → B =
C) ↔ [A / x]B =
C)) |
29 | 1, 28 | sylan 457 |
1
⊢ ((A ∈ V ∧
ℲxC) → (∀x(x = A →
B = C)
↔ [A / x]B =
C)) |