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Metamath Proof Explorer

Theorem nn0zi

Description: A nonnegative integer is an integer. (Contributed by Mario Carneiro, 18-Feb-2014)

		Ref	Expression
	Hypothesis	nn0zi.1	$⊢ N \in ℕ_{0}$
	Assertion	nn0zi	$⊢ N \in ℤ$

Step	Hyp	Ref	Expression
1		nn0zi.1	$⊢ N \in ℕ_{0}$
2		nn0ssz	$⊢ ℕ_{0} \subseteq ℤ$
3	2 1	sselii	$⊢ N \in ℤ$