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Metamath Proof Explorer

Theorem ioossre

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

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

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