Theorem ioossre

Description: An open interval is a set of reals. (Contributed by NM, 31-May-2007)

	Ref	Expression
Assertion	ioossre	$$⊢\left(A,B\right)\subseteq ℝ$$

Proof

Step	Hyp	Ref	Expression
1		elioore	$$⊢x\in \left(A,B\right)\to x\in ℝ$$
2	1	ssriv	$$⊢\left(A,B\right)\subseteq ℝ$$