Metamath Proof Explorer


Theorem ntrclsfv2

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 ∈ 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 ntrclsfv2 ⊢ φ → D ⁡ K = I

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 1 2 3 ntrclsnvobr ⊢ φ → K D I
5 1 2 4 ntrclsfv1 ⊢ φ → D ⁡ K = I