Theorem neufal

Description: There does not exist exactly one set such that F. is true. (Contributed by Anthony Hart, 13-Sep-2011)

	Ref	Expression
Assertion	neufal	$$⊢\neg \exists !x\perp$$

Proof

Step	Hyp	Ref	Expression
1		nexfal	$$⊢\neg \exists x\perp$$
2		euex	$$⊢\exists !x\perp \to \exists x\perp$$
3	1 2	mto	$$⊢\neg \exists !x\perp$$