Theorem fofun

Description: An onto mapping is a function. (Contributed by NM, 29-Mar-2008)

	Ref	Expression
Assertion	fofun	⊢ ( 𝐹 : 𝐴 –onto→ 𝐵 → Fun 𝐹 )

Proof

Step	Hyp	Ref	Expression
1		fof	⊢ ( 𝐹 : 𝐴 –onto→ 𝐵 → 𝐹 : 𝐴 ⟶ 𝐵 )
2	1	ffund	⊢ ( 𝐹 : 𝐴 –onto→ 𝐵 → Fun 𝐹 )