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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 e. RR -> A e. RR* )

Proof

Step Hyp Ref Expression
1 ressxr 
 |-  RR C_ RR*
2 1 sseli 
 |-  ( A e. RR -> A e. RR* )