Theorem xnegeqi

Description: Equality of two extended numbers with -e in front of them. (Contributed by Glauco Siliprandi, 2-Jan-2022)

	Ref	Expression
Hypothesis	xnegeqi.1	|- A = B
Assertion	xnegeqi	|- -e A = -e B

Proof

Step	Hyp	Ref	Expression
1		xnegeqi.1	|- A = B
2		xnegeq	|- ( A = B -> -e A = -e B )
3	1 2	ax-mp	|- -e A = -e B