Proof of Theorem raaan
| Step | Hyp | Ref
 | Expression | 
| 1 |   | raaan.1 | 
. . . 4
⊢
Ⅎ𝑦𝜑 | 
| 2 |   | raaan.2 | 
. . . 4
⊢
Ⅎ𝑥𝜓 | 
| 3 | 1, 2 | raaanlem 3555 | 
. . 3
⊢
(∃𝑥 𝑥 ∈ 𝐴 → (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝜑 ∧ 𝜓) ↔ (∀𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑦 ∈ 𝐴 𝜓))) | 
| 4 | 3 | pm5.74i 180 | 
. 2
⊢
((∃𝑥 𝑥 ∈ 𝐴 → ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝜑 ∧ 𝜓)) ↔ (∃𝑥 𝑥 ∈ 𝐴 → (∀𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑦 ∈ 𝐴 𝜓))) | 
| 5 |   | ralm 3554 | 
. 2
⊢
((∃𝑥 𝑥 ∈ 𝐴 → ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝜑 ∧ 𝜓)) ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝜑 ∧ 𝜓)) | 
| 6 |   | jcab 603 | 
. . 3
⊢
((∃𝑥 𝑥 ∈ 𝐴 → (∀𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑦 ∈ 𝐴 𝜓)) ↔ ((∃𝑥 𝑥 ∈ 𝐴 → ∀𝑥 ∈ 𝐴 𝜑) ∧ (∃𝑥 𝑥 ∈ 𝐴 → ∀𝑦 ∈ 𝐴 𝜓))) | 
| 7 |   | ralm 3554 | 
. . . 4
⊢
((∃𝑥 𝑥 ∈ 𝐴 → ∀𝑥 ∈ 𝐴 𝜑) ↔ ∀𝑥 ∈ 𝐴 𝜑) | 
| 8 |   | eleq1 2259 | 
. . . . . . 7
⊢ (𝑥 = 𝑦 → (𝑥 ∈ 𝐴 ↔ 𝑦 ∈ 𝐴)) | 
| 9 | 8 | cbvexv 1933 | 
. . . . . 6
⊢
(∃𝑥 𝑥 ∈ 𝐴 ↔ ∃𝑦 𝑦 ∈ 𝐴) | 
| 10 | 9 | imbi1i 238 | 
. . . . 5
⊢
((∃𝑥 𝑥 ∈ 𝐴 → ∀𝑦 ∈ 𝐴 𝜓) ↔ (∃𝑦 𝑦 ∈ 𝐴 → ∀𝑦 ∈ 𝐴 𝜓)) | 
| 11 |   | ralm 3554 | 
. . . . 5
⊢
((∃𝑦 𝑦 ∈ 𝐴 → ∀𝑦 ∈ 𝐴 𝜓) ↔ ∀𝑦 ∈ 𝐴 𝜓) | 
| 12 | 10, 11 | bitri 184 | 
. . . 4
⊢
((∃𝑥 𝑥 ∈ 𝐴 → ∀𝑦 ∈ 𝐴 𝜓) ↔ ∀𝑦 ∈ 𝐴 𝜓) | 
| 13 | 7, 12 | anbi12i 460 | 
. . 3
⊢
(((∃𝑥 𝑥 ∈ 𝐴 → ∀𝑥 ∈ 𝐴 𝜑) ∧ (∃𝑥 𝑥 ∈ 𝐴 → ∀𝑦 ∈ 𝐴 𝜓)) ↔ (∀𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑦 ∈ 𝐴 𝜓)) | 
| 14 | 6, 13 | bitri 184 | 
. 2
⊢
((∃𝑥 𝑥 ∈ 𝐴 → (∀𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑦 ∈ 𝐴 𝜓)) ↔ (∀𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑦 ∈ 𝐴 𝜓)) | 
| 15 | 4, 5, 14 | 3bitr3i 210 | 
1
⊢
(∀𝑥 ∈
𝐴 ∀𝑦 ∈ 𝐴 (𝜑 ∧ 𝜓) ↔ (∀𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑦 ∈ 𝐴 𝜓)) |