| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | nfv 1914 | . . . 4
⊢
Ⅎ𝑥 𝐴 = 𝐷 | 
| 2 |  | nfra1 3284 | . . . 4
⊢
Ⅎ𝑥∀𝑥 ∈ 𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹) | 
| 3 | 1, 2 | nfan 1899 | . . 3
⊢
Ⅎ𝑥(𝐴 = 𝐷 ∧ ∀𝑥 ∈ 𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹)) | 
| 4 |  | nfv 1914 | . . . 4
⊢
Ⅎ𝑦 𝐴 = 𝐷 | 
| 5 |  | nfcv 2905 | . . . . 5
⊢
Ⅎ𝑦𝐴 | 
| 6 |  | nfv 1914 | . . . . . 6
⊢
Ⅎ𝑦 𝐵 = 𝐸 | 
| 7 |  | nfra1 3284 | . . . . . 6
⊢
Ⅎ𝑦∀𝑦 ∈ 𝐵 𝐶 = 𝐹 | 
| 8 | 6, 7 | nfan 1899 | . . . . 5
⊢
Ⅎ𝑦(𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹) | 
| 9 | 5, 8 | nfralw 3311 | . . . 4
⊢
Ⅎ𝑦∀𝑥 ∈ 𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹) | 
| 10 | 4, 9 | nfan 1899 | . . 3
⊢
Ⅎ𝑦(𝐴 = 𝐷 ∧ ∀𝑥 ∈ 𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹)) | 
| 11 |  | nfv 1914 | . . 3
⊢
Ⅎ𝑧(𝐴 = 𝐷 ∧ ∀𝑥 ∈ 𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹)) | 
| 12 |  | rsp 3247 | . . . . . . 7
⊢
(∀𝑥 ∈
𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹) → (𝑥 ∈ 𝐴 → (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹))) | 
| 13 |  | rsp 3247 | . . . . . . . . . 10
⊢
(∀𝑦 ∈
𝐵 𝐶 = 𝐹 → (𝑦 ∈ 𝐵 → 𝐶 = 𝐹)) | 
| 14 |  | eqeq2 2749 | . . . . . . . . . 10
⊢ (𝐶 = 𝐹 → (𝑧 = 𝐶 ↔ 𝑧 = 𝐹)) | 
| 15 | 13, 14 | syl6 35 | . . . . . . . . 9
⊢
(∀𝑦 ∈
𝐵 𝐶 = 𝐹 → (𝑦 ∈ 𝐵 → (𝑧 = 𝐶 ↔ 𝑧 = 𝐹))) | 
| 16 | 15 | pm5.32d 577 | . . . . . . . 8
⊢
(∀𝑦 ∈
𝐵 𝐶 = 𝐹 → ((𝑦 ∈ 𝐵 ∧ 𝑧 = 𝐶) ↔ (𝑦 ∈ 𝐵 ∧ 𝑧 = 𝐹))) | 
| 17 |  | eleq2 2830 | . . . . . . . . 9
⊢ (𝐵 = 𝐸 → (𝑦 ∈ 𝐵 ↔ 𝑦 ∈ 𝐸)) | 
| 18 | 17 | anbi1d 631 | . . . . . . . 8
⊢ (𝐵 = 𝐸 → ((𝑦 ∈ 𝐵 ∧ 𝑧 = 𝐹) ↔ (𝑦 ∈ 𝐸 ∧ 𝑧 = 𝐹))) | 
| 19 | 16, 18 | sylan9bbr 510 | . . . . . . 7
⊢ ((𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹) → ((𝑦 ∈ 𝐵 ∧ 𝑧 = 𝐶) ↔ (𝑦 ∈ 𝐸 ∧ 𝑧 = 𝐹))) | 
| 20 | 12, 19 | syl6 35 | . . . . . 6
⊢
(∀𝑥 ∈
𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹) → (𝑥 ∈ 𝐴 → ((𝑦 ∈ 𝐵 ∧ 𝑧 = 𝐶) ↔ (𝑦 ∈ 𝐸 ∧ 𝑧 = 𝐹)))) | 
| 21 | 20 | pm5.32d 577 | . . . . 5
⊢
(∀𝑥 ∈
𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹) → ((𝑥 ∈ 𝐴 ∧ (𝑦 ∈ 𝐵 ∧ 𝑧 = 𝐶)) ↔ (𝑥 ∈ 𝐴 ∧ (𝑦 ∈ 𝐸 ∧ 𝑧 = 𝐹)))) | 
| 22 |  | eleq2 2830 | . . . . . 6
⊢ (𝐴 = 𝐷 → (𝑥 ∈ 𝐴 ↔ 𝑥 ∈ 𝐷)) | 
| 23 | 22 | anbi1d 631 | . . . . 5
⊢ (𝐴 = 𝐷 → ((𝑥 ∈ 𝐴 ∧ (𝑦 ∈ 𝐸 ∧ 𝑧 = 𝐹)) ↔ (𝑥 ∈ 𝐷 ∧ (𝑦 ∈ 𝐸 ∧ 𝑧 = 𝐹)))) | 
| 24 | 21, 23 | sylan9bbr 510 | . . . 4
⊢ ((𝐴 = 𝐷 ∧ ∀𝑥 ∈ 𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹)) → ((𝑥 ∈ 𝐴 ∧ (𝑦 ∈ 𝐵 ∧ 𝑧 = 𝐶)) ↔ (𝑥 ∈ 𝐷 ∧ (𝑦 ∈ 𝐸 ∧ 𝑧 = 𝐹)))) | 
| 25 |  | anass 468 | . . . 4
⊢ (((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝑧 = 𝐶) ↔ (𝑥 ∈ 𝐴 ∧ (𝑦 ∈ 𝐵 ∧ 𝑧 = 𝐶))) | 
| 26 |  | anass 468 | . . . 4
⊢ (((𝑥 ∈ 𝐷 ∧ 𝑦 ∈ 𝐸) ∧ 𝑧 = 𝐹) ↔ (𝑥 ∈ 𝐷 ∧ (𝑦 ∈ 𝐸 ∧ 𝑧 = 𝐹))) | 
| 27 | 24, 25, 26 | 3bitr4g 314 | . . 3
⊢ ((𝐴 = 𝐷 ∧ ∀𝑥 ∈ 𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹)) → (((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝑧 = 𝐶) ↔ ((𝑥 ∈ 𝐷 ∧ 𝑦 ∈ 𝐸) ∧ 𝑧 = 𝐹))) | 
| 28 | 3, 10, 11, 27 | oprabbid 7498 | . 2
⊢ ((𝐴 = 𝐷 ∧ ∀𝑥 ∈ 𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹)) → {〈〈𝑥, 𝑦〉, 𝑧〉 ∣ ((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝑧 = 𝐶)} = {〈〈𝑥, 𝑦〉, 𝑧〉 ∣ ((𝑥 ∈ 𝐷 ∧ 𝑦 ∈ 𝐸) ∧ 𝑧 = 𝐹)}) | 
| 29 |  | df-mpo 7436 | . 2
⊢ (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐵 ↦ 𝐶) = {〈〈𝑥, 𝑦〉, 𝑧〉 ∣ ((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝑧 = 𝐶)} | 
| 30 |  | df-mpo 7436 | . 2
⊢ (𝑥 ∈ 𝐷, 𝑦 ∈ 𝐸 ↦ 𝐹) = {〈〈𝑥, 𝑦〉, 𝑧〉 ∣ ((𝑥 ∈ 𝐷 ∧ 𝑦 ∈ 𝐸) ∧ 𝑧 = 𝐹)} | 
| 31 | 28, 29, 30 | 3eqtr4g 2802 | 1
⊢ ((𝐴 = 𝐷 ∧ ∀𝑥 ∈ 𝐴 (𝐵 = 𝐸 ∧ ∀𝑦 ∈ 𝐵 𝐶 = 𝐹)) → (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐵 ↦ 𝐶) = (𝑥 ∈ 𝐷, 𝑦 ∈ 𝐸 ↦ 𝐹)) |