Metamath Proof Explorer

Theorem nnn0

Description: The set of positive integers is nonempty. (Contributed by Glauco Siliprandi, 8-Apr-2021)

Ref Expression
Assertion nnn0 
|- NN =/= (/)

Proof

Step Hyp Ref Expression
1 1nn 
 |-  1 e. NN
2 1 ne0ii 
 |-  NN =/= (/)