Description: A set strictly dominates the empty set iff it is not empty. (Contributed by NM, 29-Jul-2004)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | 0sdom.1 | ⊢ 𝐴 ∈ V | |
| Assertion | 0sdom | ⊢ ( ∅ ≺ 𝐴 ↔ 𝐴 ≠ ∅ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0sdom.1 | ⊢ 𝐴 ∈ V | |
| 2 | 0sdomg | ⊢ ( 𝐴 ∈ V → ( ∅ ≺ 𝐴 ↔ 𝐴 ≠ ∅ ) ) | |
| 3 | 1 2 | ax-mp | ⊢ ( ∅ ≺ 𝐴 ↔ 𝐴 ≠ ∅ ) |