Theorem neli

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

	Ref	Expression
Hypothesis	neli.1	$$⊢A\notin B$$
Assertion	neli	$$⊢\neg A\in B$$

Proof

Step	Hyp	Ref	Expression
1		neli.1	$$⊢A\notin B$$
2		df-nel	$$⊢A\notin B\leftrightarrow \neg A\in B$$
3	1 2	mpbi	$$⊢\neg A\in B$$