Proof of Theorem imainss
| Step | Hyp | Ref
| Expression |
| 1 | | 19.8a 712 |
. . . . . . . . . 10
⊢ ((y
∈ B ∧ y◡Rx) →
∃y(y ∈ B ∧
y◡Rx)) |
| 2 | | visset 1350 |
. . . . . . . . . . 11
⊢ y
∈ V |
| 3 | | visset 1350 |
. . . . . . . . . . 11
⊢ x
∈ V |
| 4 | 2, 3 | brcnv 2519 |
. . . . . . . . . 10
⊢ (y◡Rx ↔
xRy) |
| 5 | 1, 4 | sylan2br 348 |
. . . . . . . . 9
⊢ ((y
∈ B ∧ xRy) → ∃y(y ∈
B ∧ y◡Rx)) |
| 6 | 5 | ancoms 334 |
. . . . . . . 8
⊢ ((xRy ∧ y ∈
B) → ∃y(y ∈
B ∧ y◡Rx)) |
| 7 | 6 | anim2i 270 |
. . . . . . 7
⊢ ((x
∈ A ∧ (xRy ∧ y ∈
B)) → (x ∈ A ∧
∃y(y ∈ B ∧
y◡Rx))) |
| 8 | | pm3.26 256 |
. . . . . . . 8
⊢ ((xRy ∧ y ∈
B) → xRy) |
| 9 | 8 | adantl 305 |
. . . . . . 7
⊢ ((x
∈ A ∧ (xRy ∧ y ∈
B)) → xRy) |
| 10 | 7, 9 | jca 236 |
. . . . . 6
⊢ ((x
∈ A ∧ (xRy ∧ y ∈
B)) → ((x ∈ A ∧
∃y(y ∈ B ∧
y◡Rx)) ∧
xRy)) |
| 11 | 10 | anassrs 338 |
. . . . 5
⊢ (((x
∈ A ∧ xRy) ∧ y
∈ B) → ((x ∈ A ∧
∃y(y ∈ B ∧
y◡Rx)) ∧
xRy)) |
| 12 | | elin 1635 |
. . . . . . 7
⊢ (x
∈ (A ∩ (◡R
“ B)) ↔ (x ∈ A ∧
x ∈ (◡R
“ B))) |
| 13 | 3 | elima2 2607 |
. . . . . . . 8
⊢ (x
∈ (◡R “ B)
↔ ∃y(y ∈ B ∧
y◡Rx)) |
| 14 | 13 | anbi2i 367 |
. . . . . . 7
⊢ ((x
∈ A ∧ x ∈ (◡R
“ B)) ↔ (x ∈ A ∧
∃y(y ∈ B ∧
y◡Rx))) |
| 15 | 12, 14 | bitr 151 |
. . . . . 6
⊢ (x
∈ (A ∩ (◡R
“ B)) ↔ (x ∈ A ∧
∃y(y ∈ B ∧
y◡Rx))) |
| 16 | 15 | anbi1i 368 |
. . . . 5
⊢ ((x
∈ (A ∩ (◡R
“ B)) ∧ xRy) ↔ ((x
∈ A ∧ ∃y(y ∈
B ∧ y◡Rx)) ∧
xRy)) |
| 17 | 11, 16 | sylibr 175 |
. . . 4
⊢ (((x
∈ A ∧ xRy) ∧ y
∈ B) → (x ∈ (A
∩ (◡R “ B))
∧ xRy)) |
| 18 | 17 | 19.22i 723 |
. . 3
⊢ (∃x((x ∈
A ∧ xRy) ∧ y
∈ B) → ∃x(x ∈
(A ∩ (◡R
“ B)) ∧ xRy)) |
| 19 | 2 | elima2 2607 |
. . . . 5
⊢ (y
∈ (R “ A) ↔ ∃x(x ∈
A ∧ xRy)) |
| 20 | 19 | anbi1i 368 |
. . . 4
⊢ ((y
∈ (R “ A) ∧ y
∈ B) ↔ (∃x(x ∈
A ∧ xRy) ∧ y
∈ B)) |
| 21 | | elin 1635 |
. . . 4
⊢ (y
∈ ((R “ A) ∩ B)
↔ (y ∈ (R “ A)
∧ y ∈ B)) |
| 22 | | 19.41v 963 |
. . . 4
⊢ (∃x((x ∈
A ∧ xRy) ∧ y
∈ B) ↔ (∃x(x ∈
A ∧ xRy) ∧ y
∈ B)) |
| 23 | 20, 21, 22 | 3bitr4 158 |
. . 3
⊢ (y
∈ ((R “ A) ∩ B)
↔ ∃x((x ∈ A ∧
xRy) ∧
y ∈ B)) |
| 24 | 2 | elima2 2607 |
. . 3
⊢ (y
∈ (R “ (A ∩ (◡R
“ B))) ↔ ∃x(x ∈
(A ∩ (◡R
“ B)) ∧ xRy)) |
| 25 | 18, 23, 24 | 3imtr4 192 |
. 2
⊢ (y
∈ ((R “ A) ∩ B)
→ y ∈ (R “ (A
∩ (◡R “ B)))) |
| 26 | 25 | ssriv 1508 |
1
⊢ ((R
“ A) ∩ B) ⊆ (R
“ (A ∩ (◡R
“ B))) |