Step |
Hyp |
Ref |
Expression |
1 |
|
axrep4.1 |
⊢ Ⅎ 𝑧 𝜑 |
2 |
|
ax-rep |
⊢ ( ∀ 𝑥 ∃ 𝑧 ∀ 𝑦 ( ∀ 𝑧 𝜑 → 𝑦 = 𝑧 ) → ∃ 𝑧 ∀ 𝑦 ( 𝑦 ∈ 𝑧 ↔ ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ ∀ 𝑧 𝜑 ) ) ) |
3 |
1
|
19.3 |
⊢ ( ∀ 𝑧 𝜑 ↔ 𝜑 ) |
4 |
3
|
imbi1i |
⊢ ( ( ∀ 𝑧 𝜑 → 𝑦 = 𝑧 ) ↔ ( 𝜑 → 𝑦 = 𝑧 ) ) |
5 |
4
|
albii |
⊢ ( ∀ 𝑦 ( ∀ 𝑧 𝜑 → 𝑦 = 𝑧 ) ↔ ∀ 𝑦 ( 𝜑 → 𝑦 = 𝑧 ) ) |
6 |
5
|
exbii |
⊢ ( ∃ 𝑧 ∀ 𝑦 ( ∀ 𝑧 𝜑 → 𝑦 = 𝑧 ) ↔ ∃ 𝑧 ∀ 𝑦 ( 𝜑 → 𝑦 = 𝑧 ) ) |
7 |
6
|
albii |
⊢ ( ∀ 𝑥 ∃ 𝑧 ∀ 𝑦 ( ∀ 𝑧 𝜑 → 𝑦 = 𝑧 ) ↔ ∀ 𝑥 ∃ 𝑧 ∀ 𝑦 ( 𝜑 → 𝑦 = 𝑧 ) ) |
8 |
3
|
anbi2i |
⊢ ( ( 𝑥 ∈ 𝑤 ∧ ∀ 𝑧 𝜑 ) ↔ ( 𝑥 ∈ 𝑤 ∧ 𝜑 ) ) |
9 |
8
|
exbii |
⊢ ( ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ ∀ 𝑧 𝜑 ) ↔ ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ 𝜑 ) ) |
10 |
9
|
bibi2i |
⊢ ( ( 𝑦 ∈ 𝑧 ↔ ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ ∀ 𝑧 𝜑 ) ) ↔ ( 𝑦 ∈ 𝑧 ↔ ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ 𝜑 ) ) ) |
11 |
10
|
albii |
⊢ ( ∀ 𝑦 ( 𝑦 ∈ 𝑧 ↔ ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ ∀ 𝑧 𝜑 ) ) ↔ ∀ 𝑦 ( 𝑦 ∈ 𝑧 ↔ ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ 𝜑 ) ) ) |
12 |
11
|
exbii |
⊢ ( ∃ 𝑧 ∀ 𝑦 ( 𝑦 ∈ 𝑧 ↔ ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ ∀ 𝑧 𝜑 ) ) ↔ ∃ 𝑧 ∀ 𝑦 ( 𝑦 ∈ 𝑧 ↔ ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ 𝜑 ) ) ) |
13 |
2 7 12
|
3imtr3i |
⊢ ( ∀ 𝑥 ∃ 𝑧 ∀ 𝑦 ( 𝜑 → 𝑦 = 𝑧 ) → ∃ 𝑧 ∀ 𝑦 ( 𝑦 ∈ 𝑧 ↔ ∃ 𝑥 ( 𝑥 ∈ 𝑤 ∧ 𝜑 ) ) ) |