Metamath Proof Explorer


Theorem kqffn

Description: The topological indistinguishability map is a function on the base. (Contributed by Mario Carneiro, 25-Aug-2015)

Ref Expression
Hypothesis kqval.2
|- F = ( x e. X |-> { y e. J | x e. y } )
Assertion kqffn
|- ( J e. V -> F Fn X )

Proof

Step Hyp Ref Expression
1 kqval.2
 |-  F = ( x e. X |-> { y e. J | x e. y } )
2 ssrab2
 |-  { y e. J | x e. y } C_ J
3 elpw2g
 |-  ( J e. V -> ( { y e. J | x e. y } e. ~P J <-> { y e. J | x e. y } C_ J ) )
4 2 3 mpbiri
 |-  ( J e. V -> { y e. J | x e. y } e. ~P J )
5 4 adantr
 |-  ( ( J e. V /\ x e. X ) -> { y e. J | x e. y } e. ~P J )
6 5 1 fmptd
 |-  ( J e. V -> F : X --> ~P J )
7 6 ffnd
 |-  ( J e. V -> F Fn X )