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 } =/= (/) ) |