Step | Hyp | Ref
| Expression |
1 | | elxp2 5658 |
. 2
⊢
(⟨𝐴, 𝐵⟩ ∈ (𝐶 × 𝐷) ↔ ∃𝑥 ∈ 𝐶 ∃𝑦 ∈ 𝐷 ⟨𝐴, 𝐵⟩ = ⟨𝑥, 𝑦⟩) |
2 | | vex 3448 |
. . . . . . 7
⊢ 𝑥 ∈ V |
3 | | vex 3448 |
. . . . . . 7
⊢ 𝑦 ∈ V |
4 | 2, 3 | opth2 5438 |
. . . . . 6
⊢
(⟨𝐴, 𝐵⟩ = ⟨𝑥, 𝑦⟩ ↔ (𝐴 = 𝑥 ∧ 𝐵 = 𝑦)) |
5 | | eleq1 2822 |
. . . . . . 7
⊢ (𝐴 = 𝑥 → (𝐴 ∈ 𝐶 ↔ 𝑥 ∈ 𝐶)) |
6 | | eleq1 2822 |
. . . . . . 7
⊢ (𝐵 = 𝑦 → (𝐵 ∈ 𝐷 ↔ 𝑦 ∈ 𝐷)) |
7 | 5, 6 | bi2anan9 638 |
. . . . . 6
⊢ ((𝐴 = 𝑥 ∧ 𝐵 = 𝑦) → ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷) ↔ (𝑥 ∈ 𝐶 ∧ 𝑦 ∈ 𝐷))) |
8 | 4, 7 | sylbi 216 |
. . . . 5
⊢
(⟨𝐴, 𝐵⟩ = ⟨𝑥, 𝑦⟩ → ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷) ↔ (𝑥 ∈ 𝐶 ∧ 𝑦 ∈ 𝐷))) |
9 | 8 | biimprcd 250 |
. . . 4
⊢ ((𝑥 ∈ 𝐶 ∧ 𝑦 ∈ 𝐷) → (⟨𝐴, 𝐵⟩ = ⟨𝑥, 𝑦⟩ → (𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷))) |
10 | 9 | rexlimivv 3193 |
. . 3
⊢
(∃𝑥 ∈
𝐶 ∃𝑦 ∈ 𝐷 ⟨𝐴, 𝐵⟩ = ⟨𝑥, 𝑦⟩ → (𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷)) |
11 | | eqid 2733 |
. . . 4
⊢
⟨𝐴, 𝐵⟩ = ⟨𝐴, 𝐵⟩ |
12 | | opeq1 4831 |
. . . . . 6
⊢ (𝑥 = 𝐴 → ⟨𝑥, 𝑦⟩ = ⟨𝐴, 𝑦⟩) |
13 | 12 | eqeq2d 2744 |
. . . . 5
⊢ (𝑥 = 𝐴 → (⟨𝐴, 𝐵⟩ = ⟨𝑥, 𝑦⟩ ↔ ⟨𝐴, 𝐵⟩ = ⟨𝐴, 𝑦⟩)) |
14 | | opeq2 4832 |
. . . . . 6
⊢ (𝑦 = 𝐵 → ⟨𝐴, 𝑦⟩ = ⟨𝐴, 𝐵⟩) |
15 | 14 | eqeq2d 2744 |
. . . . 5
⊢ (𝑦 = 𝐵 → (⟨𝐴, 𝐵⟩ = ⟨𝐴, 𝑦⟩ ↔ ⟨𝐴, 𝐵⟩ = ⟨𝐴, 𝐵⟩)) |
16 | 13, 15 | rspc2ev 3591 |
. . . 4
⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷 ∧ ⟨𝐴, 𝐵⟩ = ⟨𝐴, 𝐵⟩) → ∃𝑥 ∈ 𝐶 ∃𝑦 ∈ 𝐷 ⟨𝐴, 𝐵⟩ = ⟨𝑥, 𝑦⟩) |
17 | 11, 16 | mp3an3 1451 |
. . 3
⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷) → ∃𝑥 ∈ 𝐶 ∃𝑦 ∈ 𝐷 ⟨𝐴, 𝐵⟩ = ⟨𝑥, 𝑦⟩) |
18 | 10, 17 | impbii 208 |
. 2
⊢
(∃𝑥 ∈
𝐶 ∃𝑦 ∈ 𝐷 ⟨𝐴, 𝐵⟩ = ⟨𝑥, 𝑦⟩ ↔ (𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷)) |
19 | 1, 18 | bitri 275 |
1
⊢
(⟨𝐴, 𝐵⟩ ∈ (𝐶 × 𝐷) ↔ (𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷)) |