| Step |
Hyp |
Ref |
Expression |
| 1 |
|
n0 |
⊢ ( 𝐴 ≠ ∅ ↔ ∃ 𝑧 𝑧 ∈ 𝐴 ) |
| 2 |
|
ttukey2g |
⊢ ( ( ∪ 𝐴 ∈ dom card ∧ 𝑧 ∈ 𝐴 ∧ ∀ 𝑥 ( 𝑥 ∈ 𝐴 ↔ ( 𝒫 𝑥 ∩ Fin ) ⊆ 𝐴 ) ) → ∃ 𝑥 ∈ 𝐴 ( 𝑧 ⊆ 𝑥 ∧ ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) ) |
| 3 |
|
simpr |
⊢ ( ( 𝑧 ⊆ 𝑥 ∧ ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) → ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) |
| 4 |
3
|
reximi |
⊢ ( ∃ 𝑥 ∈ 𝐴 ( 𝑧 ⊆ 𝑥 ∧ ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) → ∃ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) |
| 5 |
2 4
|
syl |
⊢ ( ( ∪ 𝐴 ∈ dom card ∧ 𝑧 ∈ 𝐴 ∧ ∀ 𝑥 ( 𝑥 ∈ 𝐴 ↔ ( 𝒫 𝑥 ∩ Fin ) ⊆ 𝐴 ) ) → ∃ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) |
| 6 |
5
|
3exp |
⊢ ( ∪ 𝐴 ∈ dom card → ( 𝑧 ∈ 𝐴 → ( ∀ 𝑥 ( 𝑥 ∈ 𝐴 ↔ ( 𝒫 𝑥 ∩ Fin ) ⊆ 𝐴 ) → ∃ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) ) ) |
| 7 |
6
|
exlimdv |
⊢ ( ∪ 𝐴 ∈ dom card → ( ∃ 𝑧 𝑧 ∈ 𝐴 → ( ∀ 𝑥 ( 𝑥 ∈ 𝐴 ↔ ( 𝒫 𝑥 ∩ Fin ) ⊆ 𝐴 ) → ∃ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) ) ) |
| 8 |
1 7
|
biimtrid |
⊢ ( ∪ 𝐴 ∈ dom card → ( 𝐴 ≠ ∅ → ( ∀ 𝑥 ( 𝑥 ∈ 𝐴 ↔ ( 𝒫 𝑥 ∩ Fin ) ⊆ 𝐴 ) → ∃ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) ) ) |
| 9 |
8
|
3imp |
⊢ ( ( ∪ 𝐴 ∈ dom card ∧ 𝐴 ≠ ∅ ∧ ∀ 𝑥 ( 𝑥 ∈ 𝐴 ↔ ( 𝒫 𝑥 ∩ Fin ) ⊆ 𝐴 ) ) → ∃ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐴 ¬ 𝑥 ⊊ 𝑦 ) |