Metamath Proof Explorer


Theorem nnne0i

Description: A positive integer is nonzero (inference version). (Contributed by NM, 25-Aug-1999)

Ref Expression
Hypothesis nngt0.1 A
Assertion nnne0i A 0

Proof

Step Hyp Ref Expression
1 nngt0.1 A
2 1 nnrei A
3 1 nngt0i 0 < A
4 2 3 gt0ne0ii A 0