Proof of Theorem dminss
| Step | Hyp | Ref
| Expression |
| 1 | | 19.8a 712 |
. . . . . . 7
⊢ ((x
∈ A ∧ xRy) → ∃x(x ∈
A ∧ xRy)) |
| 2 | 1 | ancoms 334 |
. . . . . 6
⊢ ((xRy ∧ x ∈
A) → ∃x(x ∈
A ∧ xRy)) |
| 3 | | visset 1350 |
. . . . . . 7
⊢ y
∈ V |
| 4 | 3 | elima2 2607 |
. . . . . 6
⊢ (y
∈ (R “ A) ↔ ∃x(x ∈
A ∧ xRy)) |
| 5 | 2, 4 | sylibr 175 |
. . . . 5
⊢ ((xRy ∧ x ∈
A) → y ∈ (R
“ A)) |
| 6 | | pm3.26 256 |
. . . . . 6
⊢ ((xRy ∧ x ∈
A) → xRy) |
| 7 | | visset 1350 |
. . . . . . 7
⊢ x
∈ V |
| 8 | 3, 7 | brcnv 2519 |
. . . . . 6
⊢ (y◡Rx ↔
xRy) |
| 9 | 6, 8 | sylibr 175 |
. . . . 5
⊢ ((xRy ∧ x ∈
A) → y◡Rx) |
| 10 | 5, 9 | jca 236 |
. . . 4
⊢ ((xRy ∧ x ∈
A) → (y ∈ (R
“ A) ∧ y◡Rx)) |
| 11 | 10 | 19.22i 723 |
. . 3
⊢ (∃y(xRy ∧
x ∈ A) → ∃y(y ∈
(R “ A) ∧ y◡Rx)) |
| 12 | 7 | eldm 2527 |
. . . . 5
⊢ (x
∈ dom R ↔ ∃y xRy) |
| 13 | 12 | anbi1i 368 |
. . . 4
⊢ ((x
∈ dom R ∧ x ∈ A)
↔ (∃y xRy ∧ x ∈
A)) |
| 14 | | elin 1635 |
. . . 4
⊢ (x
∈ (dom R ∩ A) ↔ (x
∈ dom R ∧ x ∈ A)) |
| 15 | | 19.41v 963 |
. . . 4
⊢ (∃y(xRy ∧
x ∈ A) ↔ (∃y xRy ∧
x ∈ A)) |
| 16 | 13, 14, 15 | 3bitr4 158 |
. . 3
⊢ (x<¶I>
∈ (dom R ∩ A) ↔ ∃y(xRy ∧
x ∈ A)) |
| 17 | 7 | elima2 2607 |
. . 3
⊢ (x
∈ (◡R “ (R
“ A)) ↔ ∃y(y ∈
(R “ A) ∧ y◡Rx)) |
| 18 | 11, 16, 17 | 3imtr4 192 |
. 2
⊢ (x
∈ (dom R ∩ A) → x
∈ (◡R “ (R
“ A))) |
| 19 | 18 | ssriv 1508 |
1
⊢ (dom R
∩ A) ⊆ (◡R
“ (R “ A)) |