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 ∈ ℕ
Assertion nnne0i ⊢ A ≠ 0

Proof

Step Hyp Ref Expression
1 nngt0.1 ⊢ A ∈ ℕ
2 1 nnrei ⊢ A ∈ ℝ
3 1 nngt0i ⊢ 0 < A
4 2 3 gt0ne0ii ⊢ A ≠ 0