Metamath Proof Explorer


Definition df-f

Description: Define a function (mapping) with domain and codomain. Definition 6.15(3) of TakeutiZaring p. 27. F : A --> B can be read as " F is a function from A to B ". For alternate definitions, see dff2 , dff3 , and dff4 . (Contributed by NM, 1-Aug-1994)

Ref Expression
Assertion df-f
|- ( F : A --> B <-> ( F Fn A /\ ran F C_ B ) )

Detailed syntax breakdown

Step Hyp Ref Expression
0 cF
 |-  F
1 cA
 |-  A
2 cB
 |-  B
3 1 2 0 wf
 |-  F : A --> B
4 0 1 wfn
 |-  F Fn A
5 0 crn
 |-  ran F
6 5 2 wss
 |-  ran F C_ B
7 4 6 wa
 |-  ( F Fn A /\ ran F C_ B )
8 3 7 wb
 |-  ( F : A --> B <-> ( F Fn A /\ ran F C_ B ) )