Description: Membership in universal class of ordered pairs. (Contributed by NM, 4-Jul-1994) (Proof shortened by BJ, 16-Oct-2026)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | elvv | ⊢ ( 𝐴 ∈ ( V × V ) ↔ ∃ 𝑥 ∃ 𝑦 𝐴 = 〈 𝑥 , 𝑦 〉 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elxp2 | ⊢ ( 𝐴 ∈ ( V × V ) ↔ ∃ 𝑥 ∈ V ∃ 𝑦 ∈ V 𝐴 = 〈 𝑥 , 𝑦 〉 ) | |
| 2 | rexv | ⊢ ( ∃ 𝑥 ∈ V ∃ 𝑦 ∈ V 𝐴 = 〈 𝑥 , 𝑦 〉 ↔ ∃ 𝑥 ∃ 𝑦 ∈ V 𝐴 = 〈 𝑥 , 𝑦 〉 ) | |
| 3 | rexv | ⊢ ( ∃ 𝑦 ∈ V 𝐴 = 〈 𝑥 , 𝑦 〉 ↔ ∃ 𝑦 𝐴 = 〈 𝑥 , 𝑦 〉 ) | |
| 4 | 3 | exbii | ⊢ ( ∃ 𝑥 ∃ 𝑦 ∈ V 𝐴 = 〈 𝑥 , 𝑦 〉 ↔ ∃ 𝑥 ∃ 𝑦 𝐴 = 〈 𝑥 , 𝑦 〉 ) |
| 5 | 1 2 4 | 3bitri | ⊢ ( 𝐴 ∈ ( V × V ) ↔ ∃ 𝑥 ∃ 𝑦 𝐴 = 〈 𝑥 , 𝑦 〉 ) |