Proof of Theorem chsupsn
| Step | Hyp | Ref
| Expression |
| 1 | | snssi 1851 |
. . 3
⊢ (A
∈ Cℋ → {A} ⊆ Cℋ ) |
| 2 | | chsupval2t 5303 |
. . 3
⊢ ({A}
⊆ Cℋ → ( ∨ℋ ‘{A}) = ∩{x ∈ Cℋ ∣∪{A} ⊆ x}) |
| 3 | 1, 2 | syl 12 |
. 2
⊢ (A
∈ Cℋ → ( ∨ℋ ‘{A}) = ∩{x ∈ Cℋ ∣∪{A} ⊆ x}) |
| 4 | | unisng 1933 |
. . . . . . 7
⊢ (A
∈ Cℋ → ∪{A} = A) |
| 5 | | eqimss 1548 |
. . . . . . 7
⊢ (∪{A} = A →
∪{A} ⊆
A) |
| 6 | 4, 5 | syl 12 |
. . . . . 6
⊢ (A
∈ Cℋ → ∪{A} ⊆ A) |
| 7 | 6 | ancli 244 |
. . . . 5
⊢ (A
∈ Cℋ → (A
∈ Cℋ ∧ ∪{A} ⊆ A)) |
| 8 | | sseq2 1522 |
. . . . . 6
⊢ (x =
A → (∪{A} ⊆ x ↔ ∪{A} ⊆ A)) |
| 9 | 8 | elrab 1422 |
. . . . 5
⊢ (A
∈ {x ∈ Cℋ
∣∪{A}
⊆ x} ↔ (A ∈ Cℋ ∧ ∪{A} ⊆ A)) |
| 10 | 7, 9 | sylibr 175 |
. . . 4
⊢ (A
∈ Cℋ → A
∈ {x ∈ Cℋ
∣∪{A}
⊆ x}) |
| 11 | | intss1 1979 |
. . . 4
⊢ (A
∈ {x ∈ Cℋ
∣∪{A}
⊆ x} → ∩{x ∈
Cℋ ∣∪{A} ⊆ x}
⊆ A) |
| 12 | 10, 11 | syl 12 |
. . 3
⊢ (A
∈ Cℋ → ∩{x ∈ Cℋ ∣∪{A} ⊆ x} ⊆ A) |
| 13 | | ssintub 1981 |
. . . 4
⊢ ∪{A} ⊆ ∩{x ∈ Cℋ ∣∪{A} ⊆ x} |
| 14 | 4 | sseq1d 1527 |
. . . 4
⊢ (A
∈ Cℋ → (∪{A} ⊆ ∩{x ∈ Cℋ ∣∪{A} ⊆ x} ↔ A
⊆ ∩{x
∈ Cℋ ∣∪{A} ⊆ x})) |
| 15 | 13, 14 | mpbii 168 |
. . 3
⊢ (A
∈ Cℋ → A
⊆ ∩{x
∈ Cℋ ∣∪{A} ⊆ x}) |
| 16 | 12, 15 | eqssd 1518 |
. 2
⊢ (A
∈ Cℋ → ∩{x
> ∈ Cℋ ∣∪{A} ⊆ x} = A) |
| 17 | 3, 16 | |