Proof of Theorem elrab3t
| Step | Hyp | Ref
| Expression |
| 1 | | df-rab 3437 |
. . 3
⊢ {𝑥 ∈ 𝐵 ∣ 𝜑} = {𝑥 ∣ (𝑥 ∈ 𝐵 ∧ 𝜑)} |
| 2 | 1 | eleq2i 2833 |
. 2
⊢ (𝐴 ∈ {𝑥 ∈ 𝐵 ∣ 𝜑} ↔ 𝐴 ∈ {𝑥 ∣ (𝑥 ∈ 𝐵 ∧ 𝜑)}) |
| 3 | | id 22 |
. . 3
⊢ (𝐴 ∈ 𝐵 → 𝐴 ∈ 𝐵) |
| 4 | | nfa1 2151 |
. . . . 5
⊢
Ⅎ𝑥∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) |
| 5 | | nfv 1914 |
. . . . 5
⊢
Ⅎ𝑥 𝐴 ∈ 𝐵 |
| 6 | 4, 5 | nfan 1899 |
. . . 4
⊢
Ⅎ𝑥(∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ 𝐴 ∈ 𝐵) |
| 7 | | sp 2183 |
. . . . . 6
⊢
(∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) → (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))) |
| 8 | | eleq1 2829 |
. . . . . . . . . 10
⊢ (𝑥 = 𝐴 → (𝑥 ∈ 𝐵 ↔ 𝐴 ∈ 𝐵)) |
| 9 | 8 | biimparc 479 |
. . . . . . . . 9
⊢ ((𝐴 ∈ 𝐵 ∧ 𝑥 = 𝐴) → 𝑥 ∈ 𝐵) |
| 10 | 9 | biantrurd 532 |
. . . . . . . 8
⊢ ((𝐴 ∈ 𝐵 ∧ 𝑥 = 𝐴) → (𝜑 ↔ (𝑥 ∈ 𝐵 ∧ 𝜑))) |
| 11 | 10 | bibi1d 343 |
. . . . . . 7
⊢ ((𝐴 ∈ 𝐵 ∧ 𝑥 = 𝐴) → ((𝜑 ↔ 𝜓) ↔ ((𝑥 ∈ 𝐵 ∧ 𝜑) ↔ 𝜓))) |
| 12 | 11 | pm5.74da 804 |
. . . . . 6
⊢ (𝐴 ∈ 𝐵 → ((𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ↔ (𝑥 = 𝐴 → ((𝑥 ∈ 𝐵 ∧ 𝜑) ↔ 𝜓)))) |
| 13 | 7, 12 | syl5ibcom 245 |
. . . . 5
⊢
(∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) → (𝐴 ∈ 𝐵 → (𝑥 = 𝐴 → ((𝑥 ∈ 𝐵 ∧ 𝜑) ↔ 𝜓)))) |
| 14 | 13 | imp 406 |
. . . 4
⊢
((∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ 𝐴 ∈ 𝐵) → (𝑥 = 𝐴 → ((𝑥 ∈ 𝐵 ∧ 𝜑) ↔ 𝜓))) |
| 15 | 6, 14 | alrimi 2213 |
. . 3
⊢
((∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ 𝐴 ∈ 𝐵) → ∀𝑥(𝑥 = 𝐴 → ((𝑥 ∈ 𝐵 ∧ 𝜑) ↔ 𝜓))) |
| 16 | | elabgt 3672 |
. . 3
⊢ ((𝐴 ∈ 𝐵 ∧ ∀𝑥(𝑥 = 𝐴 → ((𝑥 ∈ 𝐵 ∧ 𝜑) ↔ 𝜓))) → (𝐴 ∈ {𝑥 ∣ (𝑥 ∈ 𝐵 ∧ 𝜑)} ↔ 𝜓)) |
| 17 | 3, 15, 16 | syl2an2 686 |
. 2
⊢
((∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ 𝐴 ∈ 𝐵) → (𝐴 ∈ {𝑥 ∣ (𝑥 ∈ 𝐵 ∧ 𝜑)} ↔ 𝜓)) |
| 18 | 2, 17 | bitrid 283 |
1
⊢
((∀𝑥(𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) ∧ 𝐴 ∈ 𝐵) → (𝐴 ∈ {𝑥 ∈ 𝐵 ∣ 𝜑} ↔ 𝜓)) |