Theorem nnssq

Description: The positive integers are a subset of the rationals. (Contributed by NM, 31-Jul-2004)

	Ref	Expression
Assertion	nnssq	$$⊢\mathbb{N}\subseteq \mathbb{Q}$$

Proof

Step	Hyp	Ref	Expression
1		nnssz	$$⊢\mathbb{N}\subseteq \mathbb{Z}$$
2		zssq	$$⊢\mathbb{Z}\subseteq \mathbb{Q}$$
3	1 2	sstri	$$⊢\mathbb{N}\subseteq \mathbb{Q}$$