Metamath Proof Explorer


Theorem imcld

Description: The imaginary part of a complex number is real (closure law). (Contributed by Mario Carneiro, 29-May-2016)

Ref Expression
Hypothesis recld.1 ⊢ φ → A ∈ ℂ
Assertion imcld ⊢ φ → ℑ ⁡ A ∈ ℝ

Proof

Step Hyp Ref Expression
1 recld.1 ⊢ φ → A ∈ ℂ
2 imcl ⊢ A ∈ ℂ → ℑ ⁡ A ∈ ℝ
3 1 2 syl ⊢ φ → ℑ ⁡ A ∈ ℝ