Metamath Proof Explorer


Theorem dssmapclsntr

Description: The closure and interior operators on a topology are duals of each other. See also kur14lem2 . (Contributed by RP, 22-Apr-2021)

Ref Expression
Hypotheses dssmapclsntr.x
|- X = U. J
dssmapclsntr.k
|- K = ( cls ` J )
dssmapclsntr.i
|- I = ( int ` J )
dssmapclsntr.o
|- O = ( b e. _V |-> ( f e. ( ~P b ^m ~P b ) |-> ( s e. ~P b |-> ( b \ ( f ` ( b \ s ) ) ) ) ) )
dssmapclsntr.d
|- D = ( O ` X )
Assertion dssmapclsntr
|- ( J e. Top -> K = ( D ` I ) )

Proof

Step Hyp Ref Expression
1 dssmapclsntr.x
 |-  X = U. J
2 dssmapclsntr.k
 |-  K = ( cls ` J )
3 dssmapclsntr.i
 |-  I = ( int ` J )
4 dssmapclsntr.o
 |-  O = ( b e. _V |-> ( f e. ( ~P b ^m ~P b ) |-> ( s e. ~P b |-> ( b \ ( f ` ( b \ s ) ) ) ) ) )
5 dssmapclsntr.d
 |-  D = ( O ` X )
6 1 2 3 4 5 dssmapntrcls
 |-  ( J e. Top -> I = ( D ` K ) )
7 6 eqcomd
 |-  ( J e. Top -> ( D ` K ) = I )
8 1 topopn
 |-  ( J e. Top -> X e. J )
9 4 5 8 dssmapf1od
 |-  ( J e. Top -> D : ( ~P X ^m ~P X ) -1-1-onto-> ( ~P X ^m ~P X ) )
10 1 2 clselmap
 |-  ( J e. Top -> K e. ( ~P X ^m ~P X ) )
11 f1ocnvfv
 |-  ( ( D : ( ~P X ^m ~P X ) -1-1-onto-> ( ~P X ^m ~P X ) /\ K e. ( ~P X ^m ~P X ) ) -> ( ( D ` K ) = I -> ( `' D ` I ) = K ) )
12 9 10 11 syl2anc
 |-  ( J e. Top -> ( ( D ` K ) = I -> ( `' D ` I ) = K ) )
13 7 12 mpd
 |-  ( J e. Top -> ( `' D ` I ) = K )
14 4 5 8 dssmapnvod
 |-  ( J e. Top -> `' D = D )
15 14 fveq1d
 |-  ( J e. Top -> ( `' D ` I ) = ( D ` I ) )
16 13 15 eqtr3d
 |-  ( J e. Top -> K = ( D ` I ) )