Description: A pair containing a set is not empty. (Contributed by FL, 19-Sep-2011) (Proof shortened by JJ, 23-Jul-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | prnzg | ⊢ ( 𝐴 ∈ 𝑉 → { 𝐴 , 𝐵 } ≠ ∅ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | prid1g | ⊢ ( 𝐴 ∈ 𝑉 → 𝐴 ∈ { 𝐴 , 𝐵 } ) | |
| 2 | 1 | ne0d | ⊢ ( 𝐴 ∈ 𝑉 → { 𝐴 , 𝐵 } ≠ ∅ ) |