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