Metamath Proof Explorer


Theorem fnrnafv

Description: The range of a function expressed as a collection of the function's values, analogous to fnrnfv . (Contributed by Alexander van der Vekens, 25-May-2017)

Ref Expression
Assertion fnrnafv
|- ( F Fn A -> ran F = { y | E. x e. A y = ( F ''' x ) } )

Proof

Step Hyp Ref Expression
1 dfafn5a
 |-  ( F Fn A -> F = ( x e. A |-> ( F ''' x ) ) )
2 1 rneqd
 |-  ( F Fn A -> ran F = ran ( x e. A |-> ( F ''' x ) ) )
3 eqid
 |-  ( x e. A |-> ( F ''' x ) ) = ( x e. A |-> ( F ''' x ) )
4 3 rnmpt
 |-  ran ( x e. A |-> ( F ''' x ) ) = { y | E. x e. A y = ( F ''' x ) }
5 2 4 eqtrdi
 |-  ( F Fn A -> ran F = { y | E. x e. A y = ( F ''' x ) } )