Metamath Proof Explorer

Theorem ne0i

Description: If a class has elements, then it is nonempty. (Contributed by NM, 31-Dec-1993)

Ref Expression
Assertion ne0i 
|- ( B e. A -> A =/= (/) )

Proof

Step Hyp Ref Expression
1 n0i 
 |-  ( B e. A -> -. A = (/) )
2 1 neqned 
 |-  ( B e. A -> A =/= (/) )