| Step | Hyp | Ref
| Expression |
| 1 | | nfv 1619 |
. . . 4
⊢ Ⅎz(x ∈ A →
φ) |
| 2 | | nfcsb1v 3169 |
. . . . . 6
⊢
Ⅎx[z / x]A |
| 3 | 2 | nfcri 2484 |
. . . . 5
⊢ Ⅎx z ∈ [z /
x]A |
| 4 | | nfsbc1v 3066 |
. . . . 5
⊢ Ⅎx[̣z /
x]̣φ |
| 5 | 3, 4 | nfim 1813 |
. . . 4
⊢ Ⅎx(z ∈ [z /
x]A → [̣z / x]̣φ) |
| 6 | | id 19 |
. . . . . 6
⊢ (x = z →
x = z) |
| 7 | | csbeq1a 3145 |
. . . . . 6
⊢ (x = z →
A = [z / x]A) |
| 8 | 6, 7 | eleq12d 2421 |
. . . . 5
⊢ (x = z →
(x ∈
A ↔ z ∈
[z / x]A)) |
| 9 | | sbceq1a 3057 |
. . . . 5
⊢ (x = z →
(φ ↔ [̣z / x]̣φ)) |
| 10 | 8, 9 | imbi12d 311 |
. . . 4
⊢ (x = z →
((x ∈
A → φ) ↔ (z ∈
[z / x]A
→ [̣z / x]̣φ))) |
| 11 | 1, 5, 10 | cbval 1984 |
. . 3
⊢ (∀x(x ∈ A → φ)
↔ ∀z(z ∈ [z /
x]A → [̣z / x]̣φ)) |
| 12 | | nfcv 2490 |
. . . . . . 7
⊢
Ⅎyz |
| 13 | | cbvralcsf.1 |
. . . . . . 7
⊢
ℲyA |
| 14 | 12, 13 | nfcsb 3171 |
. . . . . 6
⊢
Ⅎy[z / x]A |
| 15 | 14 | nfcri 2484 |
. . . . 5
⊢ Ⅎy z ∈ [z /
x]A |
| 16 | | cbvralcsf.3 |
. . . . . 6
⊢ Ⅎyφ |
| 17 | 12, 16 | nfsbc 3068 |
. . . . 5
⊢ Ⅎy[̣z /
x]̣φ |
| 18 | 15, 17 | nfim 1813 |
. . . 4
⊢ Ⅎy(z ∈ [z /
x]A → [̣z / x]̣φ) |
| 19 | | nfv 1619 |
. . . 4
⊢ Ⅎz(y ∈ B →
ψ) |
| 20 | | id 19 |
. . . . . 6
⊢ (z = y →
z = y) |
| 21 | | csbeq1 3140 |
. . . . . . 7
⊢ (z = y →
[z / x]A =
[y / x]A) |
| 22 | | df-csb 3138 |
. . . . . . . 8
⊢ [y / x]A =
{v ∣
[̣y / x]̣v ∈ A} |
| 23 | | cbvralcsf.2 |
. . . . . . . . . . . 12
⊢
ℲxB |
| 24 | 23 | nfcri 2484 |
. . . . . . . . . . 11
⊢ Ⅎx v ∈ B |
| 25 | | cbvralcsf.5 |
. . . . . . . . . . . 12
⊢ (x = y →
A = B) |
| 26 | 25 | eleq2d 2420 |
. . . . . . . . . . 11
⊢ (x = y →
(v ∈
A ↔ v ∈ B)) |
| 27 | 24, 26 | sbie 2038 |
. . . . . . . . . 10
⊢ ([y / x]v ∈ A ↔ v ∈ B) |
| 28 | | sbsbc 3051 |
. . . . . . . . . 10
⊢ ([y / x]v ∈ A ↔ [̣y / x]̣v ∈ A) |
| 29 | 27, 28 | bitr3i 242 |
. . . . . . . . 9
⊢ (v ∈ B ↔ [̣y / x]̣v ∈ A) |
| 30 | 29 | eqabi 2465 |
. . . . . . . 8
⊢ B = {v ∣ [̣y /
x]̣v ∈ A} |
| 31 | 22, 30 | eqtr4i 2376 |
. . . . . . 7
⊢ [y / x]A =
B |
| 32 | 21, 31 | syl6eq 2401 |
. . . . . 6
⊢ (z = y →
[z / x]A =
B) |
| 33 | 20, 32 | eleq12d 2421 |
. . . . 5
⊢ (z = y →
(z ∈
[z / x]A
↔ y ∈ B)) |
| 34 | | dfsbcq 3049 |
. . . . . 6
⊢ (z = y →
([̣z / x]̣φ
↔ [̣y / x]̣φ)) |
| 35 | | sbsbc 3051 |
. . . . . . 7
⊢ ([y / x]φ ↔ [̣y / x]̣φ) |
| 36 | | cbvralcsf.4 |
. . . . . . . 8
⊢ Ⅎxψ |
| 37 | | cbvralcsf.6 |
. . . . . . . 8
⊢ (x = y →
(φ ↔ ψ)) |
| 38 | 36, 37 | sbie 2038 |
. . . . . . 7
⊢ ([y / x]φ ↔ ψ) |
| 39 | 35, 38 | bitr3i 242 |
. . . . . 6
⊢ ([̣y / x]̣φ
↔ ψ) |
| 40 | 34, 39 | syl6bb 252 |
. . . . 5
⊢ (z = y →
([̣z / x]̣φ
↔ ψ)) |
| 41 | 33, 40 | imbi12d 311 |
. . . 4
⊢ (z = y →
((z ∈
[z / x]A
→ [̣z / x]̣φ)
↔ (y ∈ B →
ψ))) |
| 42 | 18, 19, 41 | cbval 1984 |
. . 3
⊢ (∀z(z ∈
[z / x]A
→ [̣z / x]̣φ)
↔ ∀y(y ∈ B →
ψ)) |
| 43 | 11, 42 | bitri 240 |
. 2
⊢ (∀x(x ∈ A → φ)
↔ ∀y(y ∈ B →
ψ)) |
| 44 | | df-ral 2620 |
. 2
⊢ (∀x ∈ A φ ↔ ∀x(x ∈ A → φ)) |
| 45 | | df-ral 2620 |
. 2
⊢ (∀y ∈ B ψ ↔ ∀y(y ∈ B → ψ)) |
| 46 | 43, 44, 45 | 3bitr4i 268 |
1
⊢ (∀x ∈ A φ ↔ ∀y ∈ B ψ) |