Step |
Hyp |
Ref |
Expression |
1 |
|
axpownd |
⊢ ( ¬ 𝑥 = 𝑦 → ∃ 𝑥 ∀ 𝑦 ( ∀ 𝑥 ( ∃ 𝑧 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ) |
2 |
|
df-ex |
⊢ ( ∃ 𝑧 𝑥 ∈ 𝑦 ↔ ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 ) |
3 |
2
|
imbi1i |
⊢ ( ( ∃ 𝑧 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) ↔ ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) ) |
4 |
3
|
albii |
⊢ ( ∀ 𝑥 ( ∃ 𝑧 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) ↔ ∀ 𝑥 ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) ) |
5 |
4
|
imbi1i |
⊢ ( ( ∀ 𝑥 ( ∃ 𝑧 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ↔ ( ∀ 𝑥 ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ) |
6 |
5
|
albii |
⊢ ( ∀ 𝑦 ( ∀ 𝑥 ( ∃ 𝑧 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ↔ ∀ 𝑦 ( ∀ 𝑥 ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ) |
7 |
6
|
exbii |
⊢ ( ∃ 𝑥 ∀ 𝑦 ( ∀ 𝑥 ( ∃ 𝑧 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ↔ ∃ 𝑥 ∀ 𝑦 ( ∀ 𝑥 ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ) |
8 |
|
df-ex |
⊢ ( ∃ 𝑥 ∀ 𝑦 ( ∀ 𝑥 ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ↔ ¬ ∀ 𝑥 ¬ ∀ 𝑦 ( ∀ 𝑥 ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ) |
9 |
7 8
|
bitri |
⊢ ( ∃ 𝑥 ∀ 𝑦 ( ∀ 𝑥 ( ∃ 𝑧 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ↔ ¬ ∀ 𝑥 ¬ ∀ 𝑦 ( ∀ 𝑥 ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ) |
10 |
1 9
|
sylib |
⊢ ( ¬ 𝑥 = 𝑦 → ¬ ∀ 𝑥 ¬ ∀ 𝑦 ( ∀ 𝑥 ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) ) |
11 |
10
|
con4i |
⊢ ( ∀ 𝑥 ¬ ∀ 𝑦 ( ∀ 𝑥 ( ¬ ∀ 𝑧 ¬ 𝑥 ∈ 𝑦 → ∀ 𝑦 𝑥 ∈ 𝑧 ) → 𝑦 ∈ 𝑥 ) → 𝑥 = 𝑦 ) |