Metamath Proof Explorer


Theorem f1fun

Description: A one-to-one mapping is a function. (Contributed by NM, 8-Mar-2014)

Ref Expression
Assertion f1fun F : A 1-1 B Fun F

Proof

Step Hyp Ref Expression
1 f1fn F : A 1-1 B F Fn A
2 fnfun F Fn A Fun F
3 1 2 syl F : A 1-1 B Fun F