Theorem halfcl

Description: Closure of half of a number. (Contributed by NM, 1-Jan-2006)

	Ref	Expression
Assertion	halfcl	$$⊢A\in ℂ\to \frac{A}{2}\in ℂ$$

Proof

Step	Hyp	Ref	Expression
1		2cn	$$⊢2\in ℂ$$
2		2ne0	$$⊢2\ne 0$$
3		divcl	$$⊢\left(A\in ℂ\wedge 2\in ℂ\wedge 2\ne 0\right)\to \frac{A}{2}\in ℂ$$
4	1 2 3	mp3an23	$$⊢A\in ℂ\to \frac{A}{2}\in ℂ$$