Proof of Theorem tz6.12-2
| Step | Hyp | Ref
| Expression |
| 1 | | ax-17 925 |
. . . . . . 7
⊢ (¬ ∃!y AFy →
∀z ¬ ∃!y AFy) |
| 2 | | eq0 1719 |
. . . . . . . 8
⊢ ({x∣∃!y AFy} = ∅
↔ ∀z ¬ z ∈ {x∣∃!y AFy}) |
| 3 | | visset 1350 |
. . . . . . . . . . 11
⊢ z
∈ V |
| 4 | | pm4.2i 149 |
. . . . . . . . . . 11
⊢ (x =
z → (∃!y AFy ↔
∃!y AFy)) |
| 5 | 3, 4 | elab 1415 |
. . . . . . . . . 10
⊢ (z
∈ {x∣∃!y AFy} ↔
∃!y AFy) |
| 6 | 5 | negbii 162 |
. . . . . . . . 9
⊢ (¬ z ∈ {x∣∃!y AFy} ↔ ¬
∃!y AFy) |
| 7 | 6 | bial 695 |
. . . . . . . 8
⊢ (∀z ¬ z ∈
{x∣∃!y AFy} ↔
∀z ¬ ∃!y AFy) |
| 8 | 2, 7 | bitr2 152 |
. . . . . . 7
⊢ (∀z ¬ ∃!y AFy ↔
{x∣∃!y AFy} =
∅) |
| 9 | 1, 8 | sylib 173 |
. . . . . 6
⊢ (¬ ∃!y AFy →
{x∣∃!y AFy} =
∅) |
| 10 | 9 | sseq2d 1528 |
. . . . 5
⊢ (¬ ∃!y AFy →
((F ‘A) ⊆ {x∣∃!y AFy} ↔
(F ‘A) ⊆ ∅)) |
| 11 | | fveq2 2832 |
. . . . . . 7
⊢ (z =
A → (F ‘z) =
(F ‘A)) |
| 12 | | breq1 2065 |
. . . . . . . . 9
⊢ (z =
A → (zFy ↔ AFy)) |
| 13 | 12 | bieudv 1013 |
. . . . . . . 8
⊢ (z =
A → (∃!y zFy ↔
∃!y AFy)) |
| 14 | 13 | biabdv 1183 |
. . . . . . 7
⊢ (z =
A → {x∣∃!y zFy} = {x∣∃!y AFy}) |
| 15 | 11, 14 | sseq12d 1529 |
. . . . . 6
⊢ (z =
A → ((F ‘z)
⊆ {x∣∃!y zFy} ↔
(F ‘A) ⊆ {x∣∃!y AFy})) |
| 16 | 3 | fv3 2839 |
. . . . . . 7
⊢ (F
‘z) = {x∣(∃y(x ∈
y ∧ zFy) ∧ ∃!y zFy)} |
| 17 | | pm3.27 260 |
. . . . . . . 8
⊢ ((∃y(x ∈
y ∧ zFy) ∧ ∃!y zFy) →
∃!y zFy) |
| 18 | 17 | ss2abi 1552 |
. . . . . . 7
⊢ {x∣(∃y(x ∈
y ∧ zFy) ∧ ∃!y zFy)} ⊆
{x∣∃!y zFy} |
| 19 | 16, 18 | eqsstr 1530 |
. . . . . 6
⊢ (F
‘z) ⊆ {x∣∃!y zFy} |
| 20 | 15, 19 | vtoclg 1383 |
. . . . 5
⊢ (A
∈ V → (F ‘A) ⊆ {x∣∃!y AFy}) |
| 21 | 10, 20 | syl5bi 183 |
. . . 4
⊢ (¬ ∃!y AFy →
(A ∈ V → (F ‘A)
⊆ ∅)) |
| 22 | 21 | com12 13 |
. . 3
⊢ (A
∈ V → (¬ ∃!y
AFy →
(F ‘A) ⊆ ∅)) |
| 23 | | ss0 1727 |
. . 3
⊢ ((F
‘A) ⊆ ∅ → (F ‘A) =
∅) |
| 24 | 22, 23 | syl6 23 |
. 2
⊢ (A
∈ V → (¬ ∃!y
AFy →
(F ‘A) = ∅)) |
| 25 | | fvprc 2829 |
. . 3
⊢ (¬ A ∈ V → (F ‘A) =
∅) |
| 26 | 25 | a1d 14 |
. 2
⊢ (¬ A ∈ V → (¬ ∃!y AFy →
(F ‘A) = ∅)) |
| 27 | 24, 26 | pm2.61i 110 |
1
⊢ (¬ ∃!y AFy →
(F ‘A) = ∅) |