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Metamath Proof Explorer

Theorem relen

Description: Equinumerosity is a relation. (Contributed by NM, 28-Mar-1998)

		Ref	Expression
	Assertion	relen	$⊢ Rel \approx$

Step	Hyp	Ref	Expression
1		df-en	$⊢ \approx = \{⟨x, y⟩ \| \exists f f : x \underset{1-1 onto}{⟶} y\}$
2	1	relopabiv	$⊢ Rel \approx$