Theorem rphalfcld

Description: Closure law for half of a positive real. (Contributed by Mario Carneiro, 28-May-2016)

	Ref	Expression
Hypothesis	rpred.1	$$⊢\phi \to A\in {ℝ}^{+}$$
Assertion	rphalfcld	$$⊢\phi \to \frac{A}{2}\in {ℝ}^{+}$$

Proof

Step	Hyp	Ref	Expression
1		rpred.1	$$⊢\phi \to A\in {ℝ}^{+}$$
2		rphalfcl	$$⊢A\in {ℝ}^{+}\to \frac{A}{2}\in {ℝ}^{+}$$
3	1 2	syl	$$⊢\phi \to \frac{A}{2}\in {ℝ}^{+}$$