Step |
Hyp |
Ref |
Expression |
1 |
|
sbralie.1 |
⊢ ( 𝑥 = 𝑦 → ( 𝜑 ↔ 𝜓 ) ) |
2 |
|
df-ral |
⊢ ( ∀ 𝑥 ∈ 𝑦 𝜑 ↔ ∀ 𝑥 ( 𝑥 ∈ 𝑦 → 𝜑 ) ) |
3 |
|
sbim |
⊢ ( [ 𝑦 / 𝑧 ] ( 𝑥 ∈ 𝑧 → 𝜑 ) ↔ ( [ 𝑦 / 𝑧 ] 𝑥 ∈ 𝑧 → [ 𝑦 / 𝑧 ] 𝜑 ) ) |
4 |
|
elsb2 |
⊢ ( [ 𝑦 / 𝑧 ] 𝑥 ∈ 𝑧 ↔ 𝑥 ∈ 𝑦 ) |
5 |
|
sbv |
⊢ ( [ 𝑦 / 𝑧 ] 𝜑 ↔ 𝜑 ) |
6 |
4 5
|
imbi12i |
⊢ ( ( [ 𝑦 / 𝑧 ] 𝑥 ∈ 𝑧 → [ 𝑦 / 𝑧 ] 𝜑 ) ↔ ( 𝑥 ∈ 𝑦 → 𝜑 ) ) |
7 |
3 6
|
bitri |
⊢ ( [ 𝑦 / 𝑧 ] ( 𝑥 ∈ 𝑧 → 𝜑 ) ↔ ( 𝑥 ∈ 𝑦 → 𝜑 ) ) |
8 |
7
|
albii |
⊢ ( ∀ 𝑥 [ 𝑦 / 𝑧 ] ( 𝑥 ∈ 𝑧 → 𝜑 ) ↔ ∀ 𝑥 ( 𝑥 ∈ 𝑦 → 𝜑 ) ) |
9 |
|
elequ1 |
⊢ ( 𝑥 = 𝑦 → ( 𝑥 ∈ 𝑧 ↔ 𝑦 ∈ 𝑧 ) ) |
10 |
9 1
|
imbi12d |
⊢ ( 𝑥 = 𝑦 → ( ( 𝑥 ∈ 𝑧 → 𝜑 ) ↔ ( 𝑦 ∈ 𝑧 → 𝜓 ) ) ) |
11 |
10
|
cbvalvw |
⊢ ( ∀ 𝑥 ( 𝑥 ∈ 𝑧 → 𝜑 ) ↔ ∀ 𝑦 ( 𝑦 ∈ 𝑧 → 𝜓 ) ) |
12 |
|
df-ral |
⊢ ( ∀ 𝑦 ∈ 𝑥 𝜓 ↔ ∀ 𝑦 ( 𝑦 ∈ 𝑥 → 𝜓 ) ) |
13 |
12
|
sbbii |
⊢ ( [ 𝑧 / 𝑥 ] ∀ 𝑦 ∈ 𝑥 𝜓 ↔ [ 𝑧 / 𝑥 ] ∀ 𝑦 ( 𝑦 ∈ 𝑥 → 𝜓 ) ) |
14 |
|
sbal |
⊢ ( [ 𝑧 / 𝑥 ] ∀ 𝑦 ( 𝑦 ∈ 𝑥 → 𝜓 ) ↔ ∀ 𝑦 [ 𝑧 / 𝑥 ] ( 𝑦 ∈ 𝑥 → 𝜓 ) ) |
15 |
|
sbim |
⊢ ( [ 𝑧 / 𝑥 ] ( 𝑦 ∈ 𝑥 → 𝜓 ) ↔ ( [ 𝑧 / 𝑥 ] 𝑦 ∈ 𝑥 → [ 𝑧 / 𝑥 ] 𝜓 ) ) |
16 |
|
elsb2 |
⊢ ( [ 𝑧 / 𝑥 ] 𝑦 ∈ 𝑥 ↔ 𝑦 ∈ 𝑧 ) |
17 |
|
sbv |
⊢ ( [ 𝑧 / 𝑥 ] 𝜓 ↔ 𝜓 ) |
18 |
16 17
|
imbi12i |
⊢ ( ( [ 𝑧 / 𝑥 ] 𝑦 ∈ 𝑥 → [ 𝑧 / 𝑥 ] 𝜓 ) ↔ ( 𝑦 ∈ 𝑧 → 𝜓 ) ) |
19 |
15 18
|
bitri |
⊢ ( [ 𝑧 / 𝑥 ] ( 𝑦 ∈ 𝑥 → 𝜓 ) ↔ ( 𝑦 ∈ 𝑧 → 𝜓 ) ) |
20 |
19
|
albii |
⊢ ( ∀ 𝑦 [ 𝑧 / 𝑥 ] ( 𝑦 ∈ 𝑥 → 𝜓 ) ↔ ∀ 𝑦 ( 𝑦 ∈ 𝑧 → 𝜓 ) ) |
21 |
13 14 20
|
3bitrri |
⊢ ( ∀ 𝑦 ( 𝑦 ∈ 𝑧 → 𝜓 ) ↔ [ 𝑧 / 𝑥 ] ∀ 𝑦 ∈ 𝑥 𝜓 ) |
22 |
11 21
|
bitri |
⊢ ( ∀ 𝑥 ( 𝑥 ∈ 𝑧 → 𝜑 ) ↔ [ 𝑧 / 𝑥 ] ∀ 𝑦 ∈ 𝑥 𝜓 ) |
23 |
22
|
sbbii |
⊢ ( [ 𝑦 / 𝑧 ] ∀ 𝑥 ( 𝑥 ∈ 𝑧 → 𝜑 ) ↔ [ 𝑦 / 𝑧 ] [ 𝑧 / 𝑥 ] ∀ 𝑦 ∈ 𝑥 𝜓 ) |
24 |
|
sbal |
⊢ ( [ 𝑦 / 𝑧 ] ∀ 𝑥 ( 𝑥 ∈ 𝑧 → 𝜑 ) ↔ ∀ 𝑥 [ 𝑦 / 𝑧 ] ( 𝑥 ∈ 𝑧 → 𝜑 ) ) |
25 |
|
sbco2vv |
⊢ ( [ 𝑦 / 𝑧 ] [ 𝑧 / 𝑥 ] ∀ 𝑦 ∈ 𝑥 𝜓 ↔ [ 𝑦 / 𝑥 ] ∀ 𝑦 ∈ 𝑥 𝜓 ) |
26 |
23 24 25
|
3bitr3i |
⊢ ( ∀ 𝑥 [ 𝑦 / 𝑧 ] ( 𝑥 ∈ 𝑧 → 𝜑 ) ↔ [ 𝑦 / 𝑥 ] ∀ 𝑦 ∈ 𝑥 𝜓 ) |
27 |
2 8 26
|
3bitr2i |
⊢ ( ∀ 𝑥 ∈ 𝑦 𝜑 ↔ [ 𝑦 / 𝑥 ] ∀ 𝑦 ∈ 𝑥 𝜓 ) |