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Metamath Proof Explorer

Theorem funrel

Description: A function is a relation. (Contributed by NM, 1-Aug-1994)

		Ref	Expression
	Assertion	funrel	$⊢ Fun A \to Rel A$

Step	Hyp	Ref	Expression
1		df-fun	$⊢ Fun A \leftrightarrow (Rel A \land A \circ A^{-1} \subseteq I)$
2	1	simplbi	$⊢ Fun A \to Rel A$