Proof of Theorem ralxpxfr2d
| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | df-ral 3062 | . . . 4
⊢
(∀𝑥 ∈
𝐵 𝜓 ↔ ∀𝑥(𝑥 ∈ 𝐵 → 𝜓)) | 
| 2 |  | ralxpxfr2d.b | . . . . . 6
⊢ (𝜑 → (𝑥 ∈ 𝐵 ↔ ∃𝑦 ∈ 𝐶 ∃𝑧 ∈ 𝐷 𝑥 = 𝐴)) | 
| 3 | 2 | imbi1d 341 | . . . . 5
⊢ (𝜑 → ((𝑥 ∈ 𝐵 → 𝜓) ↔ (∃𝑦 ∈ 𝐶 ∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓))) | 
| 4 | 3 | albidv 1920 | . . . 4
⊢ (𝜑 → (∀𝑥(𝑥 ∈ 𝐵 → 𝜓) ↔ ∀𝑥(∃𝑦 ∈ 𝐶 ∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓))) | 
| 5 | 1, 4 | bitrid 283 | . . 3
⊢ (𝜑 → (∀𝑥 ∈ 𝐵 𝜓 ↔ ∀𝑥(∃𝑦 ∈ 𝐶 ∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓))) | 
| 6 |  | ralcom4 3286 | . . . 4
⊢
(∀𝑦 ∈
𝐶 ∀𝑥∀𝑧 ∈ 𝐷 (𝑥 = 𝐴 → 𝜓) ↔ ∀𝑥∀𝑦 ∈ 𝐶 ∀𝑧 ∈ 𝐷 (𝑥 = 𝐴 → 𝜓)) | 
| 7 |  | ralcom4 3286 | . . . . 5
⊢
(∀𝑧 ∈
𝐷 ∀𝑥(𝑥 = 𝐴 → 𝜓) ↔ ∀𝑥∀𝑧 ∈ 𝐷 (𝑥 = 𝐴 → 𝜓)) | 
| 8 | 7 | ralbii 3093 | . . . 4
⊢
(∀𝑦 ∈
𝐶 ∀𝑧 ∈ 𝐷 ∀𝑥(𝑥 = 𝐴 → 𝜓) ↔ ∀𝑦 ∈ 𝐶 ∀𝑥∀𝑧 ∈ 𝐷 (𝑥 = 𝐴 → 𝜓)) | 
| 9 |  | r19.23v 3183 | . . . . . . 7
⊢
(∀𝑧 ∈
𝐷 (𝑥 = 𝐴 → 𝜓) ↔ (∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓)) | 
| 10 | 9 | ralbii 3093 | . . . . . 6
⊢
(∀𝑦 ∈
𝐶 ∀𝑧 ∈ 𝐷 (𝑥 = 𝐴 → 𝜓) ↔ ∀𝑦 ∈ 𝐶 (∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓)) | 
| 11 |  | r19.23v 3183 | . . . . . 6
⊢
(∀𝑦 ∈
𝐶 (∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓) ↔ (∃𝑦 ∈ 𝐶 ∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓)) | 
| 12 | 10, 11 | bitr2i 276 | . . . . 5
⊢
((∃𝑦 ∈
𝐶 ∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓) ↔ ∀𝑦 ∈ 𝐶 ∀𝑧 ∈ 𝐷 (𝑥 = 𝐴 → 𝜓)) | 
| 13 | 12 | albii 1819 | . . . 4
⊢
(∀𝑥(∃𝑦 ∈ 𝐶 ∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓) ↔ ∀𝑥∀𝑦 ∈ 𝐶 ∀𝑧 ∈ 𝐷 (𝑥 = 𝐴 → 𝜓)) | 
| 14 | 6, 8, 13 | 3bitr4ri 304 | . . 3
⊢
(∀𝑥(∃𝑦 ∈ 𝐶 ∃𝑧 ∈ 𝐷 𝑥 = 𝐴 → 𝜓) ↔ ∀𝑦 ∈ 𝐶 ∀𝑧 ∈ 𝐷 ∀𝑥(𝑥 = 𝐴 → 𝜓)) | 
| 15 | 5, 14 | bitrdi 287 | . 2
⊢ (𝜑 → (∀𝑥 ∈ 𝐵 𝜓 ↔ ∀𝑦 ∈ 𝐶 ∀𝑧 ∈ 𝐷 ∀𝑥(𝑥 = 𝐴 → 𝜓))) | 
| 16 |  | ralxpxfr2d.c | . . . . . 6
⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜓 ↔ 𝜒)) | 
| 17 | 16 | pm5.74da 804 | . . . . 5
⊢ (𝜑 → ((𝑥 = 𝐴 → 𝜓) ↔ (𝑥 = 𝐴 → 𝜒))) | 
| 18 | 17 | albidv 1920 | . . . 4
⊢ (𝜑 → (∀𝑥(𝑥 = 𝐴 → 𝜓) ↔ ∀𝑥(𝑥 = 𝐴 → 𝜒))) | 
| 19 |  | ralxpxfr2d.a | . . . . 5
⊢ 𝐴 ∈ V | 
| 20 |  | biidd 262 | . . . . 5
⊢ (𝑥 = 𝐴 → (𝜒 ↔ 𝜒)) | 
| 21 | 19, 20 | ceqsalv 3521 | . . . 4
⊢
(∀𝑥(𝑥 = 𝐴 → 𝜒) ↔ 𝜒) | 
| 22 | 18, 21 | bitrdi 287 | . . 3
⊢ (𝜑 → (∀𝑥(𝑥 = 𝐴 → 𝜓) ↔ 𝜒)) | 
| 23 | 22 | 2ralbidv 3221 | . 2
⊢ (𝜑 → (∀𝑦 ∈ 𝐶 ∀𝑧 ∈ 𝐷 ∀𝑥(𝑥 = 𝐴 → 𝜓) ↔ ∀𝑦 ∈ 𝐶 ∀𝑧 ∈ 𝐷 𝜒)) | 
| 24 | 15, 23 | bitrd 279 | 1
⊢ (𝜑 → (∀𝑥 ∈ 𝐵 𝜓 ↔ ∀𝑦 ∈ 𝐶 ∀𝑧 ∈ 𝐷 𝜒)) |