Metamath Proof Explorer


Theorem 1nn0

Description: 1 is a nonnegative integer. (Contributed by Raph Levien, 10-Dec-2002)

Ref Expression
Assertion 1nn0 ⊢ 1 ∈ ℕ 0

Proof

Step Hyp Ref Expression
1 1nn ⊢ 1 ∈ ℕ
2 1 nnnn0i ⊢ 1 ∈ ℕ 0