Description: The real part of a complex number is real (closure law). (Contributed by Mario Carneiro, 29-May-2016)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | recld.1 | |- ( ph -> A e. CC ) |
|
| Assertion | recld | |- ( ph -> ( Re ` A ) e. RR ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | recld.1 | |- ( ph -> A e. CC ) |
|
| 2 | recl | |- ( A e. CC -> ( Re ` A ) e. RR ) |
|
| 3 | 1 2 | syl | |- ( ph -> ( Re ` A ) e. RR ) |