Metamath Proof Explorer


Theorem fsovfvfvd

Description: Value of the operator, ( A O B ) , which maps between maps from one base set to subsets of the second to maps from the second base set to subsets of the first for base sets, A and B , when applied to function F and element Y . (Contributed by RP, 25-Apr-2021)

Ref Expression
Hypotheses fsovd.fs
|- O = ( a e. _V , b e. _V |-> ( f e. ( ~P b ^m a ) |-> ( y e. b |-> { x e. a | y e. ( f ` x ) } ) ) )
fsovd.a
|- ( ph -> A e. V )
fsovd.b
|- ( ph -> B e. W )
fsovfvd.g
|- G = ( A O B )
fsovfvd.f
|- ( ph -> F e. ( ~P B ^m A ) )
fsovfvfvd.h
|- H = ( G ` F )
fsovfvfvd.y
|- ( ph -> Y e. B )
Assertion fsovfvfvd
|- ( ph -> ( H ` Y ) = { x e. A | Y e. ( F ` x ) } )

Proof

Step Hyp Ref Expression
1 fsovd.fs
 |-  O = ( a e. _V , b e. _V |-> ( f e. ( ~P b ^m a ) |-> ( y e. b |-> { x e. a | y e. ( f ` x ) } ) ) )
2 fsovd.a
 |-  ( ph -> A e. V )
3 fsovd.b
 |-  ( ph -> B e. W )
4 fsovfvd.g
 |-  G = ( A O B )
5 fsovfvd.f
 |-  ( ph -> F e. ( ~P B ^m A ) )
6 fsovfvfvd.h
 |-  H = ( G ` F )
7 fsovfvfvd.y
 |-  ( ph -> Y e. B )
8 1 2 3 4 5 fsovfvd
 |-  ( ph -> ( G ` F ) = ( y e. B |-> { x e. A | y e. ( F ` x ) } ) )
9 6 8 syl5eq
 |-  ( ph -> H = ( y e. B |-> { x e. A | y e. ( F ` x ) } ) )
10 eleq1
 |-  ( y = Y -> ( y e. ( F ` x ) <-> Y e. ( F ` x ) ) )
11 10 rabbidv
 |-  ( y = Y -> { x e. A | y e. ( F ` x ) } = { x e. A | Y e. ( F ` x ) } )
12 11 adantl
 |-  ( ( ph /\ y = Y ) -> { x e. A | y e. ( F ` x ) } = { x e. A | Y e. ( F ` x ) } )
13 rabexg
 |-  ( A e. V -> { x e. A | Y e. ( F ` x ) } e. _V )
14 2 13 syl
 |-  ( ph -> { x e. A | Y e. ( F ` x ) } e. _V )
15 9 12 7 14 fvmptd
 |-  ( ph -> ( H ` Y ) = { x e. A | Y e. ( F ` x ) } )