Proof of Theorem soeq1
| Step | Hyp | Ref
| Expression |
| 1 | | poeq1 2130 |
. . 3
⊢ (R =
S → (R Po A ↔
S Po A)) |
| 2 | | breq 2064 |
. . . . . 6
⊢ (R =
S → (xRy ↔ xSy)) |
| 3 | | pm4.2i 149 |
. . . . . 6
⊢ (R =
S → (x = y ↔
x = y)) |
| 4 | | breq 2064 |
. . . . . 6
⊢ (R =
S → (yRx ↔ ySx)) |
| 5 | 2, 3, 4 | bi3ord 635 |
. . . . 5
⊢ (R =
S → ((xRy ∨ x =
y ∨ yRx) ↔ (xSy ∨ x =
y ∨ ySx))) |
| 6 | 5 | biraldv 1219 |
. . . 4
⊢ (R =
S → (∀y ∈ A
(xRy ∨ x = y ∨
yRx) ↔
∀y ∈ A (xSy ∨ x = y ∨
ySx))) |
| 7 | 6 | biraldv 1219 |
. . 3
⊢ (R =
S → (∀x ∈ A
∀y ∈ A (xRy ∨ x = y ∨
yRx) ↔
∀x ∈ A ∀y
∈ A (xSy ∨ x =
y ∨ ySx))) |
| 8 | 1, 7 | anbi12d 476 |
. 2
⊢ (R =
S → ((R Po A ∧
∀x ∈ A ∀y
∈ A (xRy ∨ x =
y ∨ yRx)) ↔ (S Po
A ∧ ∀x ∈ A
∀y ∈ A (xSy ∨ x = y ∨
ySx)))) |
| 9 | | df-so 2138 |
. 2
⊢ (R Or
A ↔ (R Po A ∧
∀x ∈ A ∀y
∈ A (xRy ∨ x =
y ∨ yRx))) |
| 10 | | df-so 2138 |
. 2
⊢ (S Or
A ↔ (S Po A ∧
∀x ∈ A ∀y
∈ A (xSy ∨ x =
y ∨ ySx))) |
| 11 | 8, 9, 10 | 3bitr4g 428 |
1
⊢ (R =
S → (R Or A ↔
S Or A)) |