---
title:         Properties of distributive lattice isomorphisms
author:        Ayberk Tosun
date-started:  2024-06-01
dates-updated: [2024-06-09]
---

In this module, we collect properties of distributive lattice isomorphisms.

\begin{code}

{-# OPTIONS --safe --without-K #-}

open import MLTT.Spartan hiding (𝟚; ₀; ₁)
open import UF.FunExt
open import UF.PropTrunc
open import UF.Size
open import UF.Subsingletons
open import UF.UA-FunExt
open import UF.Univalence

module Locales.DistributiveLattice.Isomorphism-Properties
        (ua : Univalence)
        (pt : propositional-truncations-exist)
        (sr : Set-Replacement pt)
       where

private
 fe : Fun-Ext
 fe {𝓤} {𝓥} = univalence-gives-funext' 𝓤 𝓥 (ua 𝓤) (ua (𝓤 ⊔ 𝓥))

 pe : Prop-Ext
 pe {𝓤} = univalence-gives-propext (ua 𝓤)

open import Locales.DistributiveLattice.Definition fe pt
open import Locales.DistributiveLattice.Isomorphism fe pt
open import Locales.SIP.DistributiveLatticeSIP ua pt sr
open import UF.Logic

open AllCombinators pt fe renaming (_∧_ to _∧ₚ_)

\end{code}

We work in a module parameterized by 𝓤-distributive-lattices `K` and `L`.

\begin{code}

module DistributiveLatticeIsomorphismProperties
        (K : DistributiveLattice 𝓤)
        (L : DistributiveLattice 𝓤)
       where

 open DistributiveLatticeIsomorphisms K L

\end{code}

Transport lemma for distributive lattices.

\begin{code}

 ≅d≅-transport : (K L : DistributiveLattice 𝓤)
               → (B : DistributiveLattice 𝓤 → 𝓣 ̇ )
               → K ≅d≅ L
               → B K
               → B L
 ≅d≅-transport K L B iso = transport B †
  where
   † : K ＝ L
   † = isomorphic-distributive-lattices-are-equal K L iso

\end{code}

Added on 2024-06-09.

Distributive lattice isomorphisms are symmetric.

\begin{code}

≅d-sym : (K : DistributiveLattice 𝓤)
       → (L : DistributiveLattice 𝓥)
       → K ≅d≅ L → L ≅d≅ K
≅d-sym K L 𝒾 =
 record
  { 𝓈           = 𝓇 𝒾
  ; 𝓇           = 𝓈 𝒾
  ; r-cancels-s = s-cancels-r 𝒾
  ; s-cancels-r = r-cancels-s 𝒾
 }
   where
    open DistributiveLatticeIsomorphisms.Isomorphismᵈᵣ

\end{code}

End of addition.