Description: The second argument of a binary relation exists. (An artifact of our ordered pair definition.) (Contributed by Mario Carneiro, 26-Apr-2015)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | brrelexi.1 | ⊢ Rel 𝑅 | |
| Assertion | brrelex2i | ⊢ ( 𝐴 𝑅 𝐵 → 𝐵 ∈ V ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | brrelexi.1 | ⊢ Rel 𝑅 | |
| 2 | brrelex2 | ⊢ ( ( Rel 𝑅 ∧ 𝐴 𝑅 𝐵 ) → 𝐵 ∈ V ) | |
| 3 | 1 2 | mpan | ⊢ ( 𝐴 𝑅 𝐵 → 𝐵 ∈ V ) |