Metamath Proof Explorer


Theorem cjmulrcli

Description: A complex number times its conjugate is real. (Contributed by NM, 11-May-1999)

Ref Expression
Hypothesis recl.1 ⊢ A ∈ ℂ
Assertion cjmulrcli ⊢ A ⁢ A ‾ ∈ ℝ

Proof

Step Hyp Ref Expression
1 recl.1 ⊢ A ∈ ℂ
2 cjmulrcl ⊢ A ∈ ℂ → A ⁢ A ‾ ∈ ℝ
3 1 2 ax-mp ⊢ A ⁢ A ‾ ∈ ℝ