Theorem fdmi 5051

Description: The domain of a mapping. (Contributed by NM, 28-Jul-2008.)

Hypothesis

Ref	Expression
fdmi.1	|- F : A --> B

Assertion

Ref	Expression
fdmi	|- dom F = A

Proof of Theorem fdmi

Step	Hyp	Ref	Expression
1		fdmi.1	. 2 |- F : A --> B
2		fdm 5050	. 2 |- ( F : A --> B -> dom F = A )
3	1, 2	ax-mp 7	1 |- dom F = A

Syntax hints:   = wceq 1243   dom cdm 4345   -->wf 4898

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100

This theorem depends on definitions:  df-bi 110  df-fn 4905  df-f 4906

This theorem is referenced by:  eluzel2  8478