Detailed syntax breakdown of Definition df-op
Step | Hyp | Ref
| Expression |
1 | | cA |
. . 3
class A |
2 | | cB |
. . 3
class B |
3 | 1, 2 | cop 4562 |
. 2
class 〈A, B〉 |
4 | | vx |
. . . . . . 7
setvar x |
5 | 4 | cv 1641 |
. . . . . 6
class x |
6 | | vy |
. . . . . . . 8
setvar y |
7 | 6 | cv 1641 |
. . . . . . 7
class y |
8 | 7 | cphi 4563 |
. . . . . 6
class Phi
y |
9 | 5, 8 | wceq 1642 |
. . . . 5
wff x =
Phi y |
10 | 9, 6, 1 | wrex 2616 |
. . . 4
wff ∃y ∈ A x = Phi y |
11 | 10, 4 | cab 2339 |
. . 3
class {x ∣ ∃y ∈ A x = Phi y} |
12 | | c0c 4375 |
. . . . . . . 8
class 0c |
13 | 12 | csn 3738 |
. . . . . . 7
class
{0c} |
14 | 8, 13 | cun 3208 |
. . . . . 6
class ( Phi
y ∪
{0c}) |
15 | 5, 14 | wceq 1642 |
. . . . 5
wff x =
( Phi y ∪
{0c}) |
16 | 15, 6, 2 | wrex 2616 |
. . . 4
wff ∃y ∈ B x = ( Phi y ∪ {0c}) |
17 | 16, 4 | cab 2339 |
. . 3
class {x ∣ ∃y ∈ B x = ( Phi y ∪ {0c})} |
18 | 11, 17 | cun 3208 |
. 2
class ({x ∣ ∃y ∈ A x = Phi y} ∪ {x
∣ ∃y ∈ B x = ( Phi y ∪ {0c})}) |
19 | 3, 18 | wceq 1642 |
1
wff 〈A, B〉 = ({x ∣ ∃y ∈ A x = Phi y} ∪ {x
∣ ∃y ∈ B x = ( Phi y ∪ {0c})}) |