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 )