Theorem neli

Description: Inference associated with df-nel . (Contributed by BJ, 7-Jul-2018)

	Ref	Expression
Hypothesis	neli.1	|- A e/ B
Assertion	neli	|- -. A e. B

Proof

Step	Hyp	Ref	Expression
1		neli.1	|- A e/ B
2		df-nel	|- ( A e/ B <-> -. A e. B )
3	1 2	mpbi	|- -. A e. B