Theorem funrel

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

	Ref	Expression
Assertion	funrel	⊢ ( Fun 𝐴 → Rel 𝐴 )

Proof

Step	Hyp	Ref	Expression
1		df-fun	⊢ ( Fun 𝐴 ↔ ( Rel 𝐴 ∧ ( 𝐴 ∘ ◡ 𝐴 ) ⊆ I ) )
2	1	simplbi	⊢ ( Fun 𝐴 → Rel 𝐴 )