Theorem 1pneg1e0

Description: 1 + -u 1 is 0. (Contributed by David A. Wheeler, 8-Dec-2018)

	Ref	Expression
Assertion	1pneg1e0	$$⊢1+-1=0$$

Proof

Step	Hyp	Ref	Expression
1		ax-1cn	$$⊢1\in ℂ$$
2	1	negidi	$$⊢1+-1=0$$