Proof of Theorem frds
| Step | Hyp | Ref
| Expression |
| 1 | | frds.4 |
. . 3
⊢ (φ → R Fr A) |
| 2 | | dfrab2 3531 |
. . . . 5
⊢ {x ∈ A ∣ ψ} = ({x
∣ ψ}
∩ A) |
| 3 | | df-rab 2624 |
. . . . 5
⊢ {x ∈ A ∣ ψ} = {x
∣ (x
∈ A ∧ ψ)} |
| 4 | 2, 3 | eqtr3i 2375 |
. . . 4
⊢ ({x ∣ ψ} ∩ A) = {x ∣ (x ∈ A ∧ ψ)} |
| 5 | | frds.1 |
. . . . 5
⊢ {x ∣ ψ} ∈
V |
| 6 | | brex 4690 |
. . . . . . 7
⊢ (R Fr A → (R
∈ V ∧
A ∈
V)) |
| 7 | 1, 6 | syl 15 |
. . . . . 6
⊢ (φ → (R ∈ V ∧ A ∈ V)) |
| 8 | 7 | simprd 449 |
. . . . 5
⊢ (φ → A ∈
V) |
| 9 | | inexg 4101 |
. . . . 5
⊢ (({x ∣ ψ} ∈ V
∧ A ∈ V) → ({x
∣ ψ}
∩ A) ∈ V) |
| 10 | 5, 8, 9 | sylancr 644 |
. . . 4
⊢ (φ → ({x ∣ ψ} ∩ A) ∈
V) |
| 11 | 4, 10 | syl5eqelr 2438 |
. . 3
⊢ (φ → {x ∣ (x ∈ A ∧ ψ)} ∈
V) |
| 12 | | ssab2 3351 |
. . . 4
⊢ {x ∣ (x ∈ A ∧ ψ)} ⊆
A |
| 13 | 12 | a1i 10 |
. . 3
⊢ (φ → {x ∣ (x ∈ A ∧ ψ)} ⊆
A) |
| 14 | | frds.5 |
. . . . 5
⊢ (φ → ∃x ∈ A ψ) |
| 15 | | df-rex 2621 |
. . . . 5
⊢ (∃x ∈ A ψ ↔ ∃x(x ∈ A ∧ ψ)) |
| 16 | 14, 15 | sylib 188 |
. . . 4
⊢ (φ → ∃x(x ∈ A ∧ ψ)) |
| 17 | | abn0 3569 |
. . . 4
⊢ ({x ∣ (x ∈ A ∧ ψ)} ≠ ∅
↔ ∃x(x ∈ A ∧ ψ)) |
| 18 | 16, 17 | sylibr 203 |
. . 3
⊢ (φ → {x ∣ (x ∈ A ∧ ψ)} ≠ ∅) |
| 19 | 1, 11, 13, 18 | frd 5923 |
. 2
⊢ (φ → ∃y ∈ {x ∣ (x ∈ A ∧ ψ)}∀z ∈ {x ∣ (x ∈ A ∧ ψ)}
(zRy →
z = y)) |
| 20 | | eleq1 2413 |
. . . . . 6
⊢ (x = y →
(x ∈
A ↔ y ∈ A)) |
| 21 | | frds.2 |
. . . . . 6
⊢ (x = y →
(ψ ↔ χ)) |
| 22 | 20, 21 | anbi12d 691 |
. . . . 5
⊢ (x = y →
((x ∈
A ∧ ψ) ↔ (y ∈ A ∧ χ))) |
| 23 | 22 | rexab 3000 |
. . . 4
⊢ (∃y ∈ {x ∣ (x ∈ A ∧ ψ)}∀z ∈ A ((θ ∧
zRy) →
z = y)
↔ ∃y((y ∈ A ∧ χ) ∧ ∀z ∈ A ((θ
∧ zRy) → z =
y))) |
| 24 | | anass 630 |
. . . . 5
⊢ (((y ∈ A ∧ χ) ∧ ∀z ∈ A ((θ ∧
zRy) →
z = y))
↔ (y ∈ A ∧ (χ ∧ ∀z ∈ A ((θ
∧ zRy) → z =
y)))) |
| 25 | 24 | exbii 1582 |
. . . 4
⊢ (∃y((y ∈ A ∧ χ) ∧ ∀z ∈ A ((θ ∧
zRy) →
z = y))
↔ ∃y(y ∈ A ∧ (χ ∧ ∀z ∈ A ((θ
∧ zRy) → z =
y)))) |
| 26 | 23, 25 | bitri 240 |
. . 3
⊢ (∃y ∈ {x ∣ (x ∈ A ∧ ψ)}∀z ∈ A ((θ ∧
zRy) →
z = y)
↔ ∃y(y ∈ A ∧ (χ ∧ ∀z ∈ A ((θ
∧ zRy) → z =
y)))) |
| 27 | | impexp 433 |
. . . . . . 7
⊢ (((z ∈ A ∧ θ) → (zRy → z =
y)) ↔ (z ∈ A → (θ → (zRy → z =
y)))) |
| 28 | | impexp 433 |
. . . . . . . 8
⊢ (((θ ∧
zRy) →
z = y)
↔ (θ → (zRy → z =
y))) |
| 29 | 28 | imbi2i 303 |
. . . . . . 7
⊢ ((z ∈ A → ((θ ∧
zRy) →
z = y))
↔ (z ∈ A →
(θ → (zRy → z =
y)))) |
| 30 | 27, 29 | bitr4i 243 |
. . . . . 6
⊢ (((z ∈ A ∧ θ) → (zRy → z =
y)) ↔ (z ∈ A → ((θ ∧
zRy) →
z = y))) |
| 31 | 30 | albii 1566 |
. . . . 5
⊢ (∀z((z ∈ A ∧ θ) → (zRy → z =
y)) ↔ ∀z(z ∈ A → ((θ ∧
zRy) →
z = y))) |
| 32 | | eleq1 2413 |
. . . . . . 7
⊢ (x = z →
(x ∈
A ↔ z ∈ A)) |
| 33 | | frds.3 |
. . . . . . 7
⊢ (x = z →
(ψ ↔ θ)) |
| 34 | 32, 33 | anbi12d 691 |
. . . . . 6
⊢ (x = z →
((x ∈
A ∧ ψ) ↔ (z ∈ A ∧ θ))) |
| 35 | 34 | ralab 2998 |
. . . . 5
⊢ (∀z ∈ {x ∣ (x ∈ A ∧ ψ)}
(zRy →
z = y)
↔ ∀z((z ∈ A ∧ θ)
→ (zRy →
z = y))) |
| 36 | | df-ral 2620 |
. . . . 5
⊢ (∀z ∈ A ((θ ∧
zRy) →
z = y)
↔ ∀z(z ∈ A →
((θ ∧ zRy) →
z = y))) |
| 37 | 31, 35, 36 | 3bitr4i 268 |
. . . 4
⊢ (∀z ∈ {x ∣ (x ∈ A ∧ ψ)}
(zRy →
z = y)
↔ ∀z ∈ A ((θ
∧ zRy) → z =
y)) |
| 38 | 37 | rexbii 2640 |
. . 3
⊢ (∃y ∈ {x ∣ (x ∈ A ∧ ψ)}∀z ∈ {x ∣ (x ∈ A ∧ ψ)}
(zRy →
z = y)
↔ ∃y ∈ {x ∣ (x ∈ A ∧ ψ)}∀z ∈ A ((θ ∧
zRy) →
z = y)) |
| 39 | | df-rex 2621 |
. . 3
⊢ (∃y ∈ A (χ ∧ ∀z ∈ A ((θ ∧
zRy) →
z = y))
↔ ∃y(y ∈ A ∧ (χ ∧ ∀z ∈ A ((θ
∧ zRy) → z =
y)))) |
| 40 | 26, 38, 39 | 3bitr4i 268 |
. 2
⊢ (∃y ∈ {x ∣ (x ∈ A ∧ ψ)}∀z ∈ {x ∣ (x ∈ A ∧ ψ)}
(zRy →
z = y)
↔ ∃y ∈ A (χ ∧ ∀z ∈ A ((θ
∧ zRy) → z =
y))) |
| 41 | 19, 40 | sylib 188 |
1
⊢ (φ → ∃y ∈ A (χ ∧ ∀z ∈ A ((θ ∧
zRy) →
z = y))) |