Theorem xnegcli

Description: Closure of extended real negative. (Contributed by Glauco Siliprandi, 2-Jan-2022)

	Ref	Expression
Hypothesis	xnegcli.1	$$⊢A\in {ℝ}^{*}$$
Assertion	xnegcli	$$⊢-A\in {ℝ}^{*}$$

Proof

Step	Hyp	Ref	Expression
1		xnegcli.1	$$⊢A\in {ℝ}^{*}$$
2		xnegcl	$$⊢A\in {ℝ}^{*}\to -A\in {ℝ}^{*}$$
3	1 2	ax-mp	$$⊢-A\in {ℝ}^{*}$$