| Step | Hyp | Ref
| Expression |
| 1 | | eleq1 2259 |
. . . . . 6
⊢ (𝐴 = 𝐵 → (𝐴 ∈ V ↔ 𝐵 ∈ V)) |
| 2 | 1 | anbi1d 465 |
. . . . 5
⊢ (𝐴 = 𝐵 → ((𝐴 ∈ V ∧ 𝐶 ∈ V) ↔ (𝐵 ∈ V ∧ 𝐶 ∈ V))) |
| 3 | | sneq 3633 |
. . . . . . 7
⊢ (𝐴 = 𝐵 → {𝐴} = {𝐵}) |
| 4 | | preq1 3699 |
. . . . . . 7
⊢ (𝐴 = 𝐵 → {𝐴, 𝐶} = {𝐵, 𝐶}) |
| 5 | 3, 4 | preq12d 3707 |
. . . . . 6
⊢ (𝐴 = 𝐵 → {{𝐴}, {𝐴, 𝐶}} = {{𝐵}, {𝐵, 𝐶}}) |
| 6 | 5 | eleq2d 2266 |
. . . . 5
⊢ (𝐴 = 𝐵 → (𝑥 ∈ {{𝐴}, {𝐴, 𝐶}} ↔ 𝑥 ∈ {{𝐵}, {𝐵, 𝐶}})) |
| 7 | 2, 6 | anbi12d 473 |
. . . 4
⊢ (𝐴 = 𝐵 → (((𝐴 ∈ V ∧ 𝐶 ∈ V) ∧ 𝑥 ∈ {{𝐴}, {𝐴, 𝐶}}) ↔ ((𝐵 ∈ V ∧ 𝐶 ∈ V) ∧ 𝑥 ∈ {{𝐵}, {𝐵, 𝐶}}))) |
| 8 | | df-3an 982 |
. . . 4
⊢ ((𝐴 ∈ V ∧ 𝐶 ∈ V ∧ 𝑥 ∈ {{𝐴}, {𝐴, 𝐶}}) ↔ ((𝐴 ∈ V ∧ 𝐶 ∈ V) ∧ 𝑥 ∈ {{𝐴}, {𝐴, 𝐶}})) |
| 9 | | df-3an 982 |
. . . 4
⊢ ((𝐵 ∈ V ∧ 𝐶 ∈ V ∧ 𝑥 ∈ {{𝐵}, {𝐵, 𝐶}}) ↔ ((𝐵 ∈ V ∧ 𝐶 ∈ V) ∧ 𝑥 ∈ {{𝐵}, {𝐵, 𝐶}})) |
| 10 | 7, 8, 9 | 3bitr4g 223 |
. . 3
⊢ (𝐴 = 𝐵 → ((𝐴 ∈ V ∧ 𝐶 ∈ V ∧ 𝑥 ∈ {{𝐴}, {𝐴, 𝐶}}) ↔ (𝐵 ∈ V ∧ 𝐶 ∈ V ∧ 𝑥 ∈ {{𝐵}, {𝐵, 𝐶}}))) |
| 11 | 10 | abbidv 2314 |
. 2
⊢ (𝐴 = 𝐵 → {𝑥 ∣ (𝐴 ∈ V ∧ 𝐶 ∈ V ∧ 𝑥 ∈ {{𝐴}, {𝐴, 𝐶}})} = {𝑥 ∣ (𝐵 ∈ V ∧ 𝐶 ∈ V ∧ 𝑥 ∈ {{𝐵}, {𝐵, 𝐶}})}) |
| 12 | | df-op 3631 |
. 2
⊢
〈𝐴, 𝐶〉 = {𝑥 ∣ (𝐴 ∈ V ∧ 𝐶 ∈ V ∧ 𝑥 ∈ {{𝐴}, {𝐴, 𝐶}})} |
| 13 | | df-op 3631 |
. 2
⊢
〈𝐵, 𝐶〉 = {𝑥 ∣ (𝐵 ∈ V ∧ 𝐶 ∈ V ∧ 𝑥 ∈ {{𝐵}, {𝐵, 𝐶}})} |
| 14 | 11, 12, 13 | 3eqtr4g 2254 |
1
⊢ (𝐴 = 𝐵 → 〈𝐴, 𝐶〉 = 〈𝐵, 𝐶〉) |