Metamath Proof Explorer


Theorem f1fun

Description: A one-to-one mapping is a function. (Contributed by NM, 8-Mar-2014) (Proof shortened by Umit Teoman Dogan, 10-Jun-2026)

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 1 fnfund F : A 1-1 B Fun F