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 } =/= (/) ) |