Theorem 1z

Description: One is an integer. (Contributed by NM, 10-May-2004)

	Ref	Expression
Assertion	1z	$$⊢1\in \mathbb{Z}$$

Proof

Step	Hyp	Ref	Expression
1		1nn	$$⊢1\in \mathbb{N}$$
2	1	nnzi	$$⊢1\in \mathbb{Z}$$