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Metamath Proof Explorer

Theorem rexr

Description: A standard real is an extended real. (Contributed by NM, 14-Oct-2005)

Ref Expression
Assertion rexr ( 𝐴 ∈ ℝ → 𝐴 ∈ ℝ* )

Proof

Step Hyp Ref Expression
1 ressxr ⊢ ℝ ⊆ ℝ*
2 1 sseli ⊢ ( 𝐴 ∈ ℝ → 𝐴 ∈ ℝ* )