Proof of Theorem inf3lema
| Step | Hyp | Ref
| Expression |
| 1 | | inf3lem.1 |
. . . . . 6
⊢ G =
{〈y, z〉∣z
= {w ∈ x∣(w ∩
x) ⊆ y}} |
| 2 | | id 9 |
. . . . . . . 8
⊢ (z =
u → z = u) |
| 3 | | sseq2 1522 |
. . . . . . . . . 10
⊢ (y =
v → ((w ∩ x)
⊆ y ↔ (w ∩ x)
⊆ v)) |
| 4 | 3 | birabsdv 1344 |
. . . . . . . . 9
⊢ (y =
v → {w ∈ x∣(w ∩
x) ⊆ y} = {w ∈
x∣(w ∩ x)
⊆ v}) |
| 5 | | ineq1 1638 |
. . . . . . . . . . 11
⊢ (w =
f → (w ∩ x) =
(f ∩ x)) |
| 6 | 5 | sseq1d 1527 |
. . . . . . . . . 10
⊢ (w =
f → ((w ∩ x)
⊆ v ↔ (f ∩ x)
⊆ v)) |
| 7 | 6 | cbvrabv 1426 |
. . . . . . . . 9
⊢ {w
∈ x∣(w ∩ x)
⊆ v} = {f ∈ x∣(f ∩
x) ⊆ v} |
| 8 | 4, 7 | syl6eq 1140 |
. . . . . . . 8
⊢ (y =
v → {w ∈ x∣(w ∩
x) ⊆ y} = {f ∈
x∣(f ∩ x)
⊆ v}) |
| 9 | 2, 8 | cleqan12rd 1117 |
. . . . . . 7
⊢ ((y =
v ∧ z = u) →
(z = {w
∈ x∣(w ∩ x)
⊆ y} ↔ u = {f ∈
x∣(f ∩ x)
⊆ v})) |
| 10 | 9 | cbvopabv 2105 |
. . . . . 6
⊢ {〈y, z〉∣z
= {w ∈ x∣(w ∩
x) ⊆ y}} = {〈v,
u〉∣u = {f ∈
x∣(f ∩ x)
⊆ v}} |
| 11 | 1, 10 | eqtr 1119 |
. . . . 5
⊢ G =
{〈v, u〉∣u
= {f ∈ x∣(f ∩
x) ⊆ v}} |
| 12 | 11 | fveq1i 2833 |
. . . 4
⊢ (G
‘B) = ({〈v, u〉∣u
= {f ∈ x∣(f ∩
x) ⊆ v}} ‘B) |
| 13 | | inf3lem.4 |
. . . . 5
⊢ B
∈ V |
| 14 | | visset 1350 |
. . . . . 6
⊢ x
∈ V |
| 15 | 14 | rabex 1706 |
. . . . 5
⊢ {f
∈ x∣(f ∩ x)
⊆ B} ∈ V |
| 16 | | sseq2 1522 |
. . . . . 6
⊢ (v =
B → ((f ∩ x)
⊆ v ↔ (f ∩ x)
⊆ B)) |
| 17 | 16 | birabsdv 1344 |
. . . . 5
⊢ (v =
B → {f ∈ x∣(f ∩
x) ⊆ v} = {f ∈
x∣(f ∩ x)
⊆ B}) |
| 18 | 13, 15, 17 | fvopab 2877 |
. . . 4
⊢ ({〈v, u〉∣u
= {f ∈ x∣(f ∩
x) ⊆ v}} ‘B) =
{f ∈ x∣(f ∩
x) ⊆ B} |
| 19 | 12, 18 | eqtr 1119 |
. . 3
⊢ (G
‘B) = {f ∈ x∣(f ∩
x) ⊆ B} |
| 20 | 19 | eleq2i 1153 |
. 2
⊢ (A
∈ (G ‘B) ↔ A
∈ {f ∈ x∣(f ∩
x) ⊆ B}) |
| 21 | | ineq1 1638 |
. . . 4
⊢ (f =
A → (f ∩ x) =
(A ∩ x)) |
| 22 | 21 | sseq1d 1527 |
. . 3
⊢ (f =
A → ((f ∩ x)
⊆ B ↔ (A ∩ x)
⊆ B)) |
| 23 | 22 | elrab 1422 |
. 2
⊢ (A
∈ {f ∈ x∣(f ∩
x) ⊆ B} ↔ (A
∈ x ∧ (A ∩ x)
⊆ B)) |
| 24 | 20, 23 | bitr 151 |
1
⊢ (A
∈ (G ‘B) ↔ (A
∈ x ∧ (A ∩ x)
⊆ B)) |