Metamath Proof Explorer


Theorem reim0bi

Description: A number is real iff its imaginary part is 0. (Contributed by NM, 29-May-1999)

Ref Expression
Hypothesis recl.1 ⊢ A ∈ ℂ
Assertion reim0bi ⊢ A ∈ ℝ ↔ ℑ ⁡ A = 0

Proof

Step Hyp Ref Expression
1 recl.1 ⊢ A ∈ ℂ
2 reim0b ⊢ A ∈ ℂ → A ∈ ℝ ↔ ℑ ⁡ A = 0
3 1 2 ax-mp ⊢ A ∈ ℝ ↔ ℑ ⁡ A = 0