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 | ||
| ntrcls.d | |||
| ntrcls.r | |||
| Assertion | ntrclsf1o | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | ntrcls.o | ||
| 2 | ntrcls.d | ||
| 3 | ntrcls.r | ||
| 4 | 2 3 | ntrclsbex | |
| 5 | 1 2 4 | dssmapf1od |