Theorem nnnn0

Description: A positive integer is a nonnegative integer. (Contributed by NM, 9-May-2004)

	Ref	Expression
Assertion	nnnn0	⊢ ( 𝐴 ∈ ℕ → 𝐴 ∈ ℕ0 )

Proof

Step	Hyp	Ref	Expression
1		nnssnn0	⊢ ℕ ⊆ ℕ0
2	1	sseli	⊢ ( 𝐴 ∈ ℕ → 𝐴 ∈ ℕ0 )