Proof of Theorem solin
| Step | Hyp | Ref
| Expression |
| 1 | | breq1 2065 |
. . . . . 6
⊢ (x =
B → (xRy ↔ BRy)) |
| 2 | | cleq1 1107 |
. . . . . 6
⊢ (x =
B → (x = y ↔
B = y)) |
| 3 | | breq2 2066 |
. . . . . 6
⊢ (x =
B → (yRx ↔ yRB)) |
| 4 | 1, 2, 3 | bi3ord 635 |
. . . . 5
⊢ (x =
B → ((xRy ∨ x =
y ∨ yRx) ↔ (BRy ∨ B =
y ∨ yRB))) |
| 5 | 4 | imbi2d 464 |
. . . 4
⊢ (x =
B → ((R Or A →
(xRy ∨ x = y ∨
yRx)) ↔
(R Or A
→ (BRy ∨ B = y ∨
yRB)))) |
| 6 | | breq2 2066 |
. . . . . 6
⊢ (y =
C → (BRy ↔ BRC)) |
| 7 | | cleq2 1110 |
. . . . . 6
⊢ (y =
C → (B = y ↔
B = C)) |
| 8 | | breq1 2065 |
. . . . . 6
⊢ (y =
C → (yRB ↔ CRB)) |
| 9 | 6, 7, 8 | bi3ord 635 |
. . . . 5
⊢ (y =
C → ((BRy ∨ B =
y ∨ yRB) ↔ (BRC ∨ B =
C ∨ CRB))) |
| 10 | 9 | imbi2d 464 |
. . . 4
⊢ (y =
C → ((R Or A →
(BRy ∨ B = y ∨
yRB)) ↔
(R Or A
→ (BRC ∨ B = C ∨
CRB)))) |
| 11 | | df-so 2138 |
. . . . . 6
⊢ (R Or
A ↔ (R Po A ∧
∀x ∈ A ∀y
∈ A (xRy ∨ x =
y ∨ yRx))) |
| 12 | | ra42 1245 |
. . . . . . 7
⊢ (∀x ∈ A
∀y ∈ A (xRy ∨ x = y ∨
yRx) →
((x ∈ A ∧ y ∈
A) → (xRy ∨ x =
y ∨ yRx))) |
| 13 | 12 | adantl 305 |
. . . . . 6
⊢ ((R Po
A ∧ ∀x ∈ A
∀y ∈ A (xRy ∨ x = y ∨
yRx)) →
((x ∈ A ∧ y ∈
A) → (xRy ∨ x =
y ∨ yRx))) |
| 14 | 11, 13 | sylbi 174 |
. . . . 5
⊢ (R Or
A → ((x ∈ A ∧
y ∈ A) → (xRy ∨ x =
y ∨ yRx))) |
| 15 | 14 | com12 13 |
. . . 4
⊢ ((x
∈ A ∧ y ∈ A)
→ (R Or A → (xRy ∨ x =
y ∨ yRx))) |
| 16 | 5, 10, 15 | vtocl2ga 1388 |
. . 3
⊢ ((B
∈ A ∧ C ∈ A)
→ (R Or A → (BRC ∨ B =
C ∨ CRB))) |
| 17 | 16 | com12 13 |
. 2
⊢ (R Or
A → ((B ∈ A ∧
C ∈ A) → (BRC ∨ B =
C ∨ CRB))) |
| 18 | 17 | imp 277 |
1
⊢ ((R Or
A ∧ (B ∈ A ∧
C ∈ A)) → (BRC ∨ B =
C ∨ CRB)) |