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 e. V -> { A , B } =/= (/) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | prid1g | |- ( A e. V -> A e. { A , B } ) |
|
| 2 | 1 | ne0d | |- ( A e. V -> { A , B } =/= (/) ) |