Metamath Proof Explorer


Theorem f1f

Description: A one-to-one mapping is a mapping. (Contributed by NM, 31-Dec-1996)

Ref Expression
Assertion f1f F : A 1-1 B F : A B

Proof

Step Hyp Ref Expression
1 df-f1 F : A 1-1 B F : A B Fun F -1
2 1 simplbi F : A 1-1 B F : A B