Theorem funforn 5276

Description: A function maps its domain onto its range. (Contributed by set.mm contributors, 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 5136	. 2 |- (Fun A <-> A Fn dom A)
2		dffn4 5275	. 2 |- (A Fn dom A <-> A:dom A-onto->ran A)
3	1, 2	bitri 240	1 |- (Fun A <-> A:dom A-onto->ran A)

Syntax hints:   <-> wb 176  dom cdm 4772  ran crn 4773  Fun wfun 4775   Fn wfn 4776  -onto->wfo 4779

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1546  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-an 360  df-cleq 2346  df-fn 4790  df-fo 4793

This theorem is referenced by: (None)