Metamath Proof Explorer

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