Description: The real part of a complex number is real (closure law). (Contributed by NM, 11-May-1999)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | recl.1 | ⊢ 𝐴 ∈ ℂ | |
| Assertion | recli | ⊢ ( ℜ ‘ 𝐴 ) ∈ ℝ |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | recl.1 | ⊢ 𝐴 ∈ ℂ | |
| 2 | recl | ⊢ ( 𝐴 ∈ ℂ → ( ℜ ‘ 𝐴 ) ∈ ℝ ) | |
| 3 | 1 2 | ax-mp | ⊢ ( ℜ ‘ 𝐴 ) ∈ ℝ |