Metamath Proof Explorer


Theorem ntrclsf1o

Description: If (pseudo-)interior and (pseudo-)closure functions are related by the duality operator we may characterize the relation as part of a 1-to-1 onto function. (Contributed by RP, 29-May-2021)

Ref Expression
Hypotheses ntrcls.o
|- O = ( i e. _V |-> ( k e. ( ~P i ^m ~P i ) |-> ( j e. ~P i |-> ( i \ ( k ` ( i \ j ) ) ) ) ) )
ntrcls.d
|- D = ( O ` B )
ntrcls.r
|- ( ph -> I D K )
Assertion ntrclsf1o
|- ( ph -> D : ( ~P B ^m ~P B ) -1-1-onto-> ( ~P B ^m ~P B ) )

Proof

Step Hyp Ref Expression
1 ntrcls.o
 |-  O = ( i e. _V |-> ( k e. ( ~P i ^m ~P i ) |-> ( j e. ~P i |-> ( i \ ( k ` ( i \ j ) ) ) ) ) )
2 ntrcls.d
 |-  D = ( O ` B )
3 ntrcls.r
 |-  ( ph -> I D K )
4 2 3 ntrclsbex
 |-  ( ph -> B e. _V )
5 1 2 4 dssmapf1od
 |-  ( ph -> D : ( ~P B ^m ~P B ) -1-1-onto-> ( ~P B ^m ~P B ) )