| Step | Hyp | Ref
| Expression |
| 1 | | csbeq1 3902 |
. . . 4
⊢ (𝑤 = 𝐴 → ⦋𝑤 / 𝑥⦌{〈𝑦, 𝑧〉 ∣ 𝜑} = ⦋𝐴 / 𝑥⦌{〈𝑦, 𝑧〉 ∣ 𝜑}) |
| 2 | | dfsbcq2 3791 |
. . . . 5
⊢ (𝑤 = 𝐴 → ([𝑤 / 𝑥]𝜑 ↔ [𝐴 / 𝑥]𝜑)) |
| 3 | 2 | opabbidv 5209 |
. . . 4
⊢ (𝑤 = 𝐴 → {〈𝑦, 𝑧〉 ∣ [𝑤 / 𝑥]𝜑} = {〈𝑦, 𝑧〉 ∣ [𝐴 / 𝑥]𝜑}) |
| 4 | 1, 3 | eqeq12d 2753 |
. . 3
⊢ (𝑤 = 𝐴 → (⦋𝑤 / 𝑥⦌{〈𝑦, 𝑧〉 ∣ 𝜑} = {〈𝑦, 𝑧〉 ∣ [𝑤 / 𝑥]𝜑} ↔ ⦋𝐴 / 𝑥⦌{〈𝑦, 𝑧〉 ∣ 𝜑} = {〈𝑦, 𝑧〉 ∣ [𝐴 / 𝑥]𝜑})) |
| 5 | | vex 3484 |
. . . 4
⊢ 𝑤 ∈ V |
| 6 | | nfs1v 2156 |
. . . . 5
⊢
Ⅎ𝑥[𝑤 / 𝑥]𝜑 |
| 7 | 6 | nfopab 5212 |
. . . 4
⊢
Ⅎ𝑥{〈𝑦, 𝑧〉 ∣ [𝑤 / 𝑥]𝜑} |
| 8 | | sbequ12 2251 |
. . . . 5
⊢ (𝑥 = 𝑤 → (𝜑 ↔ [𝑤 / 𝑥]𝜑)) |
| 9 | 8 | opabbidv 5209 |
. . . 4
⊢ (𝑥 = 𝑤 → {〈𝑦, 𝑧〉 ∣ 𝜑} = {〈𝑦, 𝑧〉 ∣ [𝑤 / 𝑥]𝜑}) |
| 10 | 5, 7, 9 | csbief 3933 |
. . 3
⊢
⦋𝑤 /
𝑥⦌{〈𝑦, 𝑧〉 ∣ 𝜑} = {〈𝑦, 𝑧〉 ∣ [𝑤 / 𝑥]𝜑} |
| 11 | 4, 10 | vtoclg 3554 |
. 2
⊢ (𝐴 ∈ V →
⦋𝐴 / 𝑥⦌{〈𝑦, 𝑧〉 ∣ 𝜑} = {〈𝑦, 𝑧〉 ∣ [𝐴 / 𝑥]𝜑}) |
| 12 | | csbprc 4409 |
. . 3
⊢ (¬
𝐴 ∈ V →
⦋𝐴 / 𝑥⦌{〈𝑦, 𝑧〉 ∣ 𝜑} = ∅) |
| 13 | | sbcex 3798 |
. . . . . . 7
⊢
([𝐴 / 𝑥]𝜑 → 𝐴 ∈ V) |
| 14 | 13 | con3i 154 |
. . . . . 6
⊢ (¬
𝐴 ∈ V → ¬
[𝐴 / 𝑥]𝜑) |
| 15 | 14 | nexdv 1936 |
. . . . 5
⊢ (¬
𝐴 ∈ V → ¬
∃𝑧[𝐴 / 𝑥]𝜑) |
| 16 | 15 | nexdv 1936 |
. . . 4
⊢ (¬
𝐴 ∈ V → ¬
∃𝑦∃𝑧[𝐴 / 𝑥]𝜑) |
| 17 | | opabn0 5558 |
. . . . 5
⊢
({〈𝑦, 𝑧〉 ∣ [𝐴 / 𝑥]𝜑} ≠ ∅ ↔ ∃𝑦∃𝑧[𝐴 / 𝑥]𝜑) |
| 18 | 17 | necon1bbii 2990 |
. . . 4
⊢ (¬
∃𝑦∃𝑧[𝐴 / 𝑥]𝜑 ↔ {〈𝑦, 𝑧〉 ∣ [𝐴 / 𝑥]𝜑} = ∅) |
| 19 | 16, 18 | sylib 218 |
. . 3
⊢ (¬
𝐴 ∈ V →
{〈𝑦, 𝑧〉 ∣ [𝐴 / 𝑥]𝜑} = ∅) |
| 20 | 12, 19 | eqtr4d 2780 |
. 2
⊢ (¬
𝐴 ∈ V →
⦋𝐴 / 𝑥⦌{〈𝑦, 𝑧〉 ∣ 𝜑} = {〈𝑦, 𝑧〉 ∣ [𝐴 / 𝑥]𝜑}) |
| 21 | 11, 20 | pm2.61i 182 |
1
⊢
⦋𝐴 /
𝑥⦌{〈𝑦, 𝑧〉 ∣ 𝜑} = {〈𝑦, 𝑧〉 ∣ [𝐴 / 𝑥]𝜑} |