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Metamath Proof Explorer

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	$⊢ \neg \exists! x ⊥$

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