Metamath Proof Explorer


Theorem fnmpti

Description: Functionality and domain of an ordered-pair class abstraction. (Contributed by NM, 29-Jan-2004) (Revised by Mario Carneiro, 31-Aug-2015)

Ref Expression
Hypotheses fnmpti.1
|- B e. _V
fnmpti.2
|- F = ( x e. A |-> B )
Assertion fnmpti
|- F Fn A

Proof

Step Hyp Ref Expression
1 fnmpti.1
 |-  B e. _V
2 fnmpti.2
 |-  F = ( x e. A |-> B )
3 1 rgenw
 |-  A. x e. A B e. _V
4 2 mptfng
 |-  ( A. x e. A B e. _V <-> F Fn A )
5 3 4 mpbi
 |-  F Fn A