Theorem xnegcld

Description: Closure of extended real negative. (Contributed by Mario Carneiro, 28-May-2016)

	Ref	Expression
Hypothesis	xnegcld.1	|- ( ph -> A e. RR* )
Assertion	xnegcld	|- ( ph -> -e A e. RR* )

Proof

Step	Hyp	Ref	Expression
1		xnegcld.1	|- ( ph -> A e. RR* )
2		xnegcl	|- ( A e. RR* -> -e A e. RR* )
3	1 2	syl	|- ( ph -> -e A e. RR* )