Description: If (pseudo-)interior and (pseudo-)closure functions are related by the duality operator then there is a functional relation between them (Contributed by RP, 28-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 | ntrclsfv2 | |- ( ph -> ( D ` K ) = I ) | 
| 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 | 1 2 3 | ntrclsnvobr | |- ( ph -> K D I ) | 
| 5 | 1 2 4 | ntrclsfv1 | |- ( ph -> ( D ` K ) = I ) |