Proof of Theorem dfoprab3s
| Step | Hyp | Ref
| Expression |
| 1 | | dfoprab2 6125 |
. 2
⊢
{〈〈𝑥,
𝑦〉, 𝑧〉 ∣ 𝜑} = {〈𝑤, 𝑧〉 ∣ ∃𝑥∃𝑦(𝑤 = 〈𝑥, 𝑦〉 ∧ 𝜑)} |
| 2 | | nfsbc1v 3070 |
. . . . 5
⊢
Ⅎ𝑥[(1st ‘𝑤) / 𝑥][(2nd ‘𝑤) / 𝑦]𝜑 |
| 3 | 2 | 19.41 1738 |
. . . 4
⊢
(∃𝑥(∃𝑦 𝑤 = 〈𝑥, 𝑦〉 ∧ [(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑) ↔ (∃𝑥∃𝑦 𝑤 = 〈𝑥, 𝑦〉 ∧ [(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑)) |
| 4 | | sbcopeq1a 6411 |
. . . . . . . 8
⊢ (𝑤 = 〈𝑥, 𝑦〉 → ([(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑 ↔ 𝜑)) |
| 5 | 4 | pm5.32i 458 |
. . . . . . 7
⊢ ((𝑤 = 〈𝑥, 𝑦〉 ∧ [(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑) ↔ (𝑤 = 〈𝑥, 𝑦〉 ∧ 𝜑)) |
| 6 | 5 | exbii 1658 |
. . . . . 6
⊢
(∃𝑦(𝑤 = 〈𝑥, 𝑦〉 ∧ [(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑) ↔ ∃𝑦(𝑤 = 〈𝑥, 𝑦〉 ∧ 𝜑)) |
| 7 | | nfcv 2392 |
. . . . . . . 8
⊢
Ⅎ𝑦(1st ‘𝑤) |
| 8 | | nfsbc1v 3070 |
. . . . . . . 8
⊢
Ⅎ𝑦[(2nd ‘𝑤) / 𝑦]𝜑 |
| 9 | 7, 8 | nfsbc 3072 |
. . . . . . 7
⊢
Ⅎ𝑦[(1st ‘𝑤) / 𝑥][(2nd ‘𝑤) / 𝑦]𝜑 |
| 10 | 9 | 19.41 1738 |
. . . . . 6
⊢
(∃𝑦(𝑤 = 〈𝑥, 𝑦〉 ∧ [(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑) ↔ (∃𝑦 𝑤 = 〈𝑥, 𝑦〉 ∧ [(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑)) |
| 11 | 6, 10 | bitr3i 186 |
. . . . 5
⊢
(∃𝑦(𝑤 = 〈𝑥, 𝑦〉 ∧ 𝜑) ↔ (∃𝑦 𝑤 = 〈𝑥, 𝑦〉 ∧ [(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑)) |
| 12 | 11 | exbii 1658 |
. . . 4
⊢
(∃𝑥∃𝑦(𝑤 = 〈𝑥, 𝑦〉 ∧ 𝜑) ↔ ∃𝑥(∃𝑦 𝑤 = 〈𝑥, 𝑦〉 ∧ [(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑)) |
| 13 | | elvv 4832 |
. . . . 5
⊢ (𝑤 ∈ (V × V) ↔
∃𝑥∃𝑦 𝑤 = 〈𝑥, 𝑦〉) |
| 14 | 13 | anbi1i 462 |
. . . 4
⊢ ((𝑤 ∈ (V × V) ∧
[(1st ‘𝑤) / 𝑥][(2nd ‘𝑤) / 𝑦]𝜑) ↔ (∃𝑥∃𝑦 𝑤 = 〈𝑥, 𝑦〉 ∧ [(1st
‘𝑤) / 𝑥][(2nd
‘𝑤) / 𝑦]𝜑)) |
| 15 | 3, 12, 14 | 3bitr4i 212 |
. . 3
⊢
(∃𝑥∃𝑦(𝑤 = 〈𝑥, 𝑦〉 ∧ 𝜑) ↔ (𝑤 ∈ (V × V) ∧
[(1st ‘𝑤) / 𝑥][(2nd ‘𝑤) / 𝑦]𝜑)) |
| 16 | 15 | opabbii 4193 |
. 2
⊢
{〈𝑤, 𝑧〉 ∣ ∃𝑥∃𝑦(𝑤 = 〈𝑥, 𝑦〉 ∧ 𝜑)} = {〈𝑤, 𝑧〉 ∣ (𝑤 ∈ (V × V) ∧
[(1st ‘𝑤) / 𝑥][(2nd ‘𝑤) / 𝑦]𝜑)} |
| 17 | 1, 16 | eqtri 2259 |
1
⊢
{〈〈𝑥,
𝑦〉, 𝑧〉 ∣ 𝜑} = {〈𝑤, 𝑧〉 ∣ (𝑤 ∈ (V × V) ∧
[(1st ‘𝑤) / 𝑥][(2nd ‘𝑤) / 𝑦]𝜑)} |