Theorem funforn 5288

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 5089	. 2 |- ( Fun A <-> A Fn dom A )
2		dffn4 5287	. 2 |- ( A Fn dom A <-> A : dom A -onto-> ran A )
3	1, 2	bitri 183	1 |- ( Fun A <-> A : dom A -onto-> ran A )

Syntax hints:   <-> wb 104   dom cdm 4477   ran crn 4478   Fun wfun 5053   Fn wfn 5054   -onto->wfo 5057

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-gen 1393  ax-ext 2082

This theorem depends on definitions:  df-bi 116  df-cleq 2093  df-fn 5062  df-fo 5065

This theorem is referenced by: (None)