Theorem funforn 5113

Description: A function maps its domain onto its range. (Contributed by NM, 23-Jul-2004.)

Assertion

Ref	Expression
funforn	|- ( Fun A <-> A : dom A -onto-> ran A )

Proof of Theorem funforn

Step	Hyp	Ref	Expression
1		funfn 4931	. 2 |- ( Fun A <-> A Fn dom A )
2		dffn4 5112	. 2 |- ( A Fn dom A <-> A : dom A -onto-> ran A )
3	1, 2	bitri 173	1 |- ( Fun A <-> A : dom A -onto-> ran A )

Syntax hints:   <-> wb 98   dom cdm 4345   ran crn 4346   Fun wfun 4896   Fn wfn 4897   -onto->wfo 4900

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-gen 1338  ax-ext 2022

This theorem depends on definitions:  df-bi 110  df-cleq 2033  df-fn 4905  df-fo 4908

This theorem is referenced by: (None)