Theorem rexrd

Description: A standard real is an extended real. (Contributed by Mario Carneiro, 28-May-2016)

	Ref	Expression
Hypothesis	rexrd.1	$$⊢\phi \to A\in ℝ$$
Assertion	rexrd	$$⊢\phi \to A\in {ℝ}^{*}$$

Proof

Step	Hyp	Ref	Expression
1		rexrd.1	$$⊢\phi \to A\in ℝ$$
2		ressxr	$$⊢ℝ\subseteq {ℝ}^{*}$$
3	2 1	sseldi	$$⊢\phi \to A\in {ℝ}^{*}$$