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Metamath Proof Explorer

Theorem 9nn0

Description: 9 is a nonnegative integer. (Contributed by Mario Carneiro, 19-Apr-2015)

Ref Expression
Assertion 9nn0 9 ∈ ℕ0

Proof

Step Hyp Ref Expression
1 9nn ⊢ 9 ∈ ℕ
2 1 nnnn0i ⊢ 9 ∈ ℕ0