Metamath Proof Explorer

Theorem f1ofun

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

Ref Expression
Assertion f1ofun 
|- ( F : A -1-1-onto-> B -> Fun F )

Proof

Step Hyp Ref Expression
1 f1ofn 
 |-  ( F : A -1-1-onto-> B -> F Fn A )
2 fnfun 
 |-  ( F Fn A -> Fun F )
3 1 2 syl 
 |-  ( F : A -1-1-onto-> B -> Fun F )