Metamath Proof Explorer

Theorem f1ofn

Description: A one-to-one onto mapping is function on its domain. (Contributed by NM, 12-Dec-2003)

Ref Expression
Assertion f1ofn 
|- ( F : A -1-1-onto-> B -> F Fn A )

Proof

Step Hyp Ref Expression
1 f1of 
 |-  ( F : A -1-1-onto-> B -> F : A --> B )
2 1 ffnd 
 |-  ( F : A -1-1-onto-> B -> F Fn A )