Proof of Theorem supeq1
| Step | Hyp | Ref
| Expression |
| 1 | | raleq 1324 |
. . . . 5
⊢ (B =
C → (∀y ∈ B ¬
xRy ↔
∀y ∈ C ¬ xRy)) |
| 2 | | rexeq 1325 |
. . . . . . 7
⊢ (B =
C → (∃z ∈ B
yRz ↔
∃z ∈ C yRz)) |
| 3 | 2 | imbi2d 464 |
. . . . . 6
⊢ (B =
C → ((yRx → ∃z ∈ B
yRz) ↔
(yRx →
∃z ∈ C yRz))) |
| 4 | 3 | biraldv 1219 |
. . . . 5
⊢ (B =
C → (∀y ∈ A
(yRx →
∃z ∈ B yRz) ↔
∀y ∈ A (yRx →
∃z ∈ C yRz))) |
| 5 | 1, 4 | anbi12d 476 |
. . . 4
⊢ (B =
C → ((∀y ∈ B ¬
xRy ∧
∀y ∈ A (yRx →
∃z ∈ B yRz)) ↔
(∀y ∈ C ¬ xRy ∧ ∀y ∈ A
(yRx →
∃z ∈ C yRz)))) |
| 6 | 5 | birabsdv 1344 |
. . 3
⊢ (B =
C → {x ∈ A∣(∀y ∈ B ¬
xRy ∧
∀y ∈ A (yRx →
∃z ∈ B yRz))} =
{x ∈ A∣(∀y ∈ C ¬
xRy ∧
∀y ∈ A (yRx →
∃z ∈ C yRz))}) |
| 7 | 6 | unieqd 1929 |
. 2
⊢ (B =
C → ∪{x ∈ A∣(∀y ∈ B ¬
xRy ∧
∀y ∈ A (yRx →
∃z ∈ B yRz))} = ∪{x ∈ A∣(∀y ∈ C ¬
xRy ∧
∀y ∈ A (yRx →
∃z ∈ C yRz))}) |
| 8 | | df-sup 2154 |
. 2
⊢ sup(B,
A, R) =
∪{x ∈
A∣(∀y ∈ B ¬
xRy ∧
∀y ∈ A (yRx →
∃z ∈ B yRz))} |
| 9 | | df-sup 2154 |
. 2
⊢ sup(C,
A, R) =
∪{x ∈
A∣(∀y ∈ C ¬
xRy ∧
∀y ∈ A (yRx →
∃z ∈ C yRz))} |
| 10 | 7, 8, 9 | 3eqtr4g 1147 |
1
⊢ (B =
C → sup(B, A, R) = sup(C,
A, R)) |