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Metamath Proof Explorer

Theorem relco

Description: A composition is a relation. Exercise 24 of TakeutiZaring p. 25. (Contributed by NM, 26-Jan-1997)

		Ref	Expression
	Assertion	relco	$⊢ Rel (A \circ B)$

Step	Hyp	Ref	Expression
1		df-co	$⊢ A \circ B = \{⟨x, y⟩ \| \exists z (x B z \land z A y)\}$
2	1	relopabiv	$⊢ Rel (A \circ B)$