Metamath Proof Explorer


Theorem re1

Description: The real part of one. (Contributed by Scott Fenton, 9-Jun-2006)

Ref Expression
Assertion re1 ( ℜ ‘ 1 ) = 1

Proof

Step Hyp Ref Expression
1 1re 1 ∈ ℝ
2 rere ( 1 ∈ ℝ → ( ℜ ‘ 1 ) = 1 )
3 1 2 ax-mp ( ℜ ‘ 1 ) = 1