Theorem bdayfun

Description: The birthday function is a function. (Contributed by Scott Fenton, 14-Jun-2011)

	Ref	Expression
Assertion	bdayfun	⊢ Fun bday

Proof

Step	Hyp	Ref	Expression
1		bdayfo	⊢ bday : No –onto→ On
2		fofun	⊢ ( bday : No –onto→ On → Fun bday )
3	1 2	ax-mp	⊢ Fun bday