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 V k 𝒫 i 𝒫 i j 𝒫 i i k i j
ntrcls.d D = O B
ntrcls.r φ I D K
Assertion ntrclsf1o φ D : 𝒫 B 𝒫 B 1-1 onto 𝒫 B 𝒫 B

Proof

Step Hyp Ref Expression
1 ntrcls.o O = i V k 𝒫 i 𝒫 i j 𝒫 i i k i j
2 ntrcls.d D = O B
3 ntrcls.r φ I D K
4 2 3 ntrclsbex φ B V
5 1 2 4 dssmapf1od φ D : 𝒫 B 𝒫 B 1-1 onto 𝒫 B 𝒫 B