Step | Hyp | Ref
| Expression |
1 | | sbcex 3721 |
. 2
⊢
([𝐴 / 𝑥]𝐵𝑅𝐶 → 𝐴 ∈ V) |
2 | | br0 5119 |
. . . 4
⊢ ¬
⦋𝐴 / 𝑥⦌𝐵∅⦋𝐴 / 𝑥⦌𝐶 |
3 | | csbprc 4337 |
. . . . 5
⊢ (¬
𝐴 ∈ V →
⦋𝐴 / 𝑥⦌𝑅 = ∅) |
4 | 3 | breqd 5081 |
. . . 4
⊢ (¬
𝐴 ∈ V →
(⦋𝐴 / 𝑥⦌𝐵⦋𝐴 / 𝑥⦌𝑅⦋𝐴 / 𝑥⦌𝐶 ↔ ⦋𝐴 / 𝑥⦌𝐵∅⦋𝐴 / 𝑥⦌𝐶)) |
5 | 2, 4 | mtbiri 326 |
. . 3
⊢ (¬
𝐴 ∈ V → ¬
⦋𝐴 / 𝑥⦌𝐵⦋𝐴 / 𝑥⦌𝑅⦋𝐴 / 𝑥⦌𝐶) |
6 | 5 | con4i 114 |
. 2
⊢
(⦋𝐴 /
𝑥⦌𝐵⦋𝐴 / 𝑥⦌𝑅⦋𝐴 / 𝑥⦌𝐶 → 𝐴 ∈ V) |
7 | | dfsbcq2 3714 |
. . 3
⊢ (𝑦 = 𝐴 → ([𝑦 / 𝑥]𝐵𝑅𝐶 ↔ [𝐴 / 𝑥]𝐵𝑅𝐶)) |
8 | | csbeq1 3831 |
. . . 4
⊢ (𝑦 = 𝐴 → ⦋𝑦 / 𝑥⦌𝐵 = ⦋𝐴 / 𝑥⦌𝐵) |
9 | | csbeq1 3831 |
. . . 4
⊢ (𝑦 = 𝐴 → ⦋𝑦 / 𝑥⦌𝑅 = ⦋𝐴 / 𝑥⦌𝑅) |
10 | | csbeq1 3831 |
. . . 4
⊢ (𝑦 = 𝐴 → ⦋𝑦 / 𝑥⦌𝐶 = ⦋𝐴 / 𝑥⦌𝐶) |
11 | 8, 9, 10 | breq123d 5084 |
. . 3
⊢ (𝑦 = 𝐴 → (⦋𝑦 / 𝑥⦌𝐵⦋𝑦 / 𝑥⦌𝑅⦋𝑦 / 𝑥⦌𝐶 ↔ ⦋𝐴 / 𝑥⦌𝐵⦋𝐴 / 𝑥⦌𝑅⦋𝐴 / 𝑥⦌𝐶)) |
12 | | nfcsb1v 3853 |
. . . . 5
⊢
Ⅎ𝑥⦋𝑦 / 𝑥⦌𝐵 |
13 | | nfcsb1v 3853 |
. . . . 5
⊢
Ⅎ𝑥⦋𝑦 / 𝑥⦌𝑅 |
14 | | nfcsb1v 3853 |
. . . . 5
⊢
Ⅎ𝑥⦋𝑦 / 𝑥⦌𝐶 |
15 | 12, 13, 14 | nfbr 5117 |
. . . 4
⊢
Ⅎ𝑥⦋𝑦 / 𝑥⦌𝐵⦋𝑦 / 𝑥⦌𝑅⦋𝑦 / 𝑥⦌𝐶 |
16 | | csbeq1a 3842 |
. . . . 5
⊢ (𝑥 = 𝑦 → 𝐵 = ⦋𝑦 / 𝑥⦌𝐵) |
17 | | csbeq1a 3842 |
. . . . 5
⊢ (𝑥 = 𝑦 → 𝑅 = ⦋𝑦 / 𝑥⦌𝑅) |
18 | | csbeq1a 3842 |
. . . . 5
⊢ (𝑥 = 𝑦 → 𝐶 = ⦋𝑦 / 𝑥⦌𝐶) |
19 | 16, 17, 18 | breq123d 5084 |
. . . 4
⊢ (𝑥 = 𝑦 → (𝐵𝑅𝐶 ↔ ⦋𝑦 / 𝑥⦌𝐵⦋𝑦 / 𝑥⦌𝑅⦋𝑦 / 𝑥⦌𝐶)) |
20 | 15, 19 | sbiev 2312 |
. . 3
⊢ ([𝑦 / 𝑥]𝐵𝑅𝐶 ↔ ⦋𝑦 / 𝑥⦌𝐵⦋𝑦 / 𝑥⦌𝑅⦋𝑦 / 𝑥⦌𝐶) |
21 | 7, 11, 20 | vtoclbg 3497 |
. 2
⊢ (𝐴 ∈ V → ([𝐴 / 𝑥]𝐵𝑅𝐶 ↔ ⦋𝐴 / 𝑥⦌𝐵⦋𝐴 / 𝑥⦌𝑅⦋𝐴 / 𝑥⦌𝐶)) |
22 | 1, 6, 21 | pm5.21nii 379 |
1
⊢
([𝐴 / 𝑥]𝐵𝑅𝐶 ↔ ⦋𝐴 / 𝑥⦌𝐵⦋𝐴 / 𝑥⦌𝑅⦋𝐴 / 𝑥⦌𝐶) |