| Step | Hyp | Ref
| Expression |
| 1 | | elex 2774 |
. 2
⊢ (𝐴 ∈ 𝑉 → 𝐴 ∈ V) |
| 2 | | elisset 2777 |
. . . . 5
⊢ (𝐴 ∈ V → ∃𝑧 𝑧 = 𝐴) |
| 3 | 2 | 3ad2ant3 1022 |
. . . 4
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) ∧ 𝐴 ∈ V) → ∃𝑧 𝑧 = 𝐴) |
| 4 | | nfnfc1 2342 |
. . . . . . 7
⊢
Ⅎ𝑥Ⅎ𝑥𝐴 |
| 5 | | nfcvd 2340 |
. . . . . . . 8
⊢
(Ⅎ𝑥𝐴 → Ⅎ𝑥𝑧) |
| 6 | | id 19 |
. . . . . . . 8
⊢
(Ⅎ𝑥𝐴 → Ⅎ𝑥𝐴) |
| 7 | 5, 6 | nfeqd 2354 |
. . . . . . 7
⊢
(Ⅎ𝑥𝐴 → Ⅎ𝑥 𝑧 = 𝐴) |
| 8 | | eqeq1 2203 |
. . . . . . . 8
⊢ (𝑧 = 𝑥 → (𝑧 = 𝐴 ↔ 𝑥 = 𝐴)) |
| 9 | 8 | a1i 9 |
. . . . . . 7
⊢
(Ⅎ𝑥𝐴 → (𝑧 = 𝑥 → (𝑧 = 𝐴 ↔ 𝑥 = 𝐴))) |
| 10 | 4, 7, 9 | cbvexd 1942 |
. . . . . 6
⊢
(Ⅎ𝑥𝐴 → (∃𝑧 𝑧 = 𝐴 ↔ ∃𝑥 𝑥 = 𝐴)) |
| 11 | 10 | ad2antrr 488 |
. . . . 5
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑)) → (∃𝑧 𝑧 = 𝐴 ↔ ∃𝑥 𝑥 = 𝐴)) |
| 12 | 11 | 3adant3 1019 |
. . . 4
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) ∧ 𝐴 ∈ V) → (∃𝑧 𝑧 = 𝐴 ↔ ∃𝑥 𝑥 = 𝐴)) |
| 13 | 3, 12 | mpbid 147 |
. . 3
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) ∧ 𝐴 ∈ V) → ∃𝑥 𝑥 = 𝐴) |
| 14 | | biimp 118 |
. . . . . . . . 9
⊢ ((𝜑 ↔ 𝜓) → (𝜑 → 𝜓)) |
| 15 | 14 | imim2i 12 |
. . . . . . . 8
⊢ ((𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) → (𝑥 = 𝐴 → (𝜑 → 𝜓))) |
| 16 | 15 | com23 78 |
. . . . . . 7
⊢ ((𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) → (𝜑 → (𝑥 = 𝐴 → 𝜓))) |
| 17 | 16 | imp 124 |
. . . . . 6
⊢ (((𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ 𝜑) → (𝑥 = 𝐴 → 𝜓)) |
| 18 | 17 | alanimi 1473 |
. . . . 5
⊢
((∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) → ∀𝑥(𝑥 = 𝐴 → 𝜓)) |
| 19 | 18 | 3ad2ant2 1021 |
. . . 4
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) ∧ 𝐴 ∈ V) → ∀𝑥(𝑥 = 𝐴 → 𝜓)) |
| 20 | | simp1r 1024 |
. . . . 5
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) ∧ 𝐴 ∈ V) → Ⅎ𝑥𝜓) |
| 21 | | 19.23t 1691 |
. . . . 5
⊢
(Ⅎ𝑥𝜓 → (∀𝑥(𝑥 = 𝐴 → 𝜓) ↔ (∃𝑥 𝑥 = 𝐴 → 𝜓))) |
| 22 | 20, 21 | syl 14 |
. . . 4
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) ∧ 𝐴 ∈ V) → (∀𝑥(𝑥 = 𝐴 → 𝜓) ↔ (∃𝑥 𝑥 = 𝐴 → 𝜓))) |
| 23 | 19, 22 | mpbid 147 |
. . 3
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) ∧ 𝐴 ∈ V) → (∃𝑥 𝑥 = 𝐴 → 𝜓)) |
| 24 | 13, 23 | mpd 13 |
. 2
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) ∧ 𝐴 ∈ V) → 𝜓) |
| 25 | 1, 24 | syl3an3 1284 |
1
⊢
(((Ⅎ𝑥𝐴 ∧ Ⅎ𝑥𝜓) ∧ (∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ ∀𝑥𝜑) ∧ 𝐴 ∈ 𝑉) → 𝜓) |