Proof of Theorem rabun2
| Step | Hyp | Ref
| Expression |
| 1 | | df-rab 3437 |
. 2
⊢ {𝑥 ∈ (𝐴 ∪ 𝐵) ∣ 𝜑} = {𝑥 ∣ (𝑥 ∈ (𝐴 ∪ 𝐵) ∧ 𝜑)} |
| 2 | | df-rab 3437 |
. . . 4
⊢ {𝑥 ∈ 𝐴 ∣ 𝜑} = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝜑)} |
| 3 | | df-rab 3437 |
. . . 4
⊢ {𝑥 ∈ 𝐵 ∣ 𝜑} = {𝑥 ∣ (𝑥 ∈ 𝐵 ∧ 𝜑)} |
| 4 | 2, 3 | uneq12i 4166 |
. . 3
⊢ ({𝑥 ∈ 𝐴 ∣ 𝜑} ∪ {𝑥 ∈ 𝐵 ∣ 𝜑}) = ({𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝜑)} ∪ {𝑥 ∣ (𝑥 ∈ 𝐵 ∧ 𝜑)}) |
| 5 | | elun 4153 |
. . . . . . 7
⊢ (𝑥 ∈ (𝐴 ∪ 𝐵) ↔ (𝑥 ∈ 𝐴 ∨ 𝑥 ∈ 𝐵)) |
| 6 | 5 | anbi1i 624 |
. . . . . 6
⊢ ((𝑥 ∈ (𝐴 ∪ 𝐵) ∧ 𝜑) ↔ ((𝑥 ∈ 𝐴 ∨ 𝑥 ∈ 𝐵) ∧ 𝜑)) |
| 7 | | andir 1011 |
. . . . . 6
⊢ (((𝑥 ∈ 𝐴 ∨ 𝑥 ∈ 𝐵) ∧ 𝜑) ↔ ((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ 𝜑))) |
| 8 | 6, 7 | bitri 275 |
. . . . 5
⊢ ((𝑥 ∈ (𝐴 ∪ 𝐵) ∧ 𝜑) ↔ ((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ 𝜑))) |
| 9 | 8 | abbii 2809 |
. . . 4
⊢ {𝑥 ∣ (𝑥 ∈ (𝐴 ∪ 𝐵) ∧ 𝜑)} = {𝑥 ∣ ((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ 𝜑))} |
| 10 | | unab 4308 |
. . . 4
⊢ ({𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝜑)} ∪ {𝑥 ∣ (𝑥 ∈ 𝐵 ∧ 𝜑)}) = {𝑥 ∣ ((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ 𝜑))} |
| 11 | 9, 10 | eqtr4i 2768 |
. . 3
⊢ {𝑥 ∣ (𝑥 ∈ (𝐴 ∪ 𝐵) ∧ 𝜑)} = ({𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝜑)} ∪ {𝑥 ∣ (𝑥 ∈ 𝐵 ∧ 𝜑)}) |
| 12 | 4, 11 | eqtr4i 2768 |
. 2
⊢ ({𝑥 ∈ 𝐴 ∣ 𝜑} ∪ {𝑥 ∈ 𝐵 ∣ 𝜑}) = {𝑥 ∣ (𝑥 ∈ (𝐴 ∪ 𝐵) ∧ 𝜑)} |
| 13 | 1, 12 | eqtr4i 2768 |
1
⊢ {𝑥 ∈ (𝐴 ∪ 𝐵) ∣ 𝜑} = ({𝑥 ∈ 𝐴 ∣ 𝜑} ∪ {𝑥 ∈ 𝐵 ∣ 𝜑}) |