Detailed syntax breakdown of Definition df-so
| Step | Hyp | Ref
| Expression |
| 1 | | cA |
. . 3
class A |
| 2 | | cR |
. . 3
class R |
| 3 | 1, 2 | wor 2917 |
. 2
wff R Or
A |
| 4 | 1, 2 | wpo 2916 |
. . 3
wff R Po
A |
| 5 | | vx |
. . . . . . . 8
set x |
| 6 | 5 | cv 991 |
. . . . . . 7
class x |
| 7 | | vy |
. . . . . . . 8
set y |
| 8 | 7 | cv 991 |
. . . . . . 7
class y |
| 9 | 6, 8, 2 | wbr 2692 |
. . . . . 6
wff xRy |
| 10 | 6, 8 | wceq 992 |
. . . . . 6
wff x =
y |
| 11 | 8, 6, 2 | wbr 2692 |
. . . . . 6
wff yRx |
| 12 | 9, 10, 11 | w3o 780 |
. . . . 5
wff (xRy ⋁ x = y ⋁ yRx) |
| 13 | 12, 7, 1 | wral 1691 |
. . . 4
wff ∀y ∈ A (xRy ⋁ x = y ⋁ yRx) |
| 14 | 13, 5, 1 | wral 1691 |
. . 3
wff ∀x ∈ A ∀y ∈ A (xRy ⋁ x = y ⋁ yRx) |
| 15 | 4, 14 | wa 221 |
. 2
wff (R Po
A ⋀
∀x
∈ A ∀y ∈ A (xRy ⋁ x = y ⋁ yRx)) |
| 16 | 3, 15 | wb 144 |
1
wff (R Or
A ↔ (R Po A ⋀ ∀x ∈ A ∀y ∈ A (xRy ⋁ x = y ⋁ yRx))) |