agda-spa/Lattice.agda
Danila Fedorin 4a90a57388 Clean up imports a bit
Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>
2023-09-23 16:39:11 -07:00

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module Lattice where
open import Equivalence
import Chain
open import Relation.Binary.Core using (_Preserves_⟶_ )
open import Relation.Nullary using (Dec; ¬_)
open import Data.Nat as Nat using ()
open import Data.Product using (_×_; Σ; _,_)
open import Data.Sum using (_⊎_; inj₁; inj₂)
open import Agda.Primitive using (lsuc; Level) renaming (_⊔_ to _⊔_)
open import Function.Definitions using (Injective)
IsDecidable : {a} {A : Set a} (R : A A Set a) Set a
IsDecidable {a} {A} R = (a₁ a₂ : A) Dec (R a₁ a₂)
record IsSemilattice {a} (A : Set a)
(_≈_ : A A Set a)
(_⊔_ : A A A) : Set a where
_≼_ : A A Set a
a b = Σ A (λ c (a c) b)
_≺_ : A A Set a
a b = (a b) × (¬ a b)
field
≈-equiv : IsEquivalence A _≈_
≈-⊔-cong : {a₁ a₂ a₃ a₄} a₁ a₂ a₃ a₄ (a₁ a₃) (a₂ a₄)
⊔-assoc : (x y z : A) ((x y) z) (x (y z))
⊔-comm : (x y : A) (x y) (y x)
⊔-idemp : (x : A) (x x) x
open IsEquivalence ≈-equiv public
≼-refl : (a : A) a a
≼-refl a = (a , ⊔-idemp a)
≼-cong : {a₁ a₂ a₃ a₄ : A} a₁ a₂ a₃ a₄ a₁ a₃ a₂ a₄
≼-cong a₁≈a₂ a₃≈a₄ (c₁ , a₁⊔c₁≈a₃) = (c₁ , ≈-trans (≈-⊔-cong (≈-sym a₁≈a₂) ≈-refl) (≈-trans a₁⊔c₁≈a₃ a₃≈a₄))
≺-cong : {a₁ a₂ a₃ a₄ : A} a₁ a₂ a₃ a₄ a₁ a₃ a₂ a₄
≺-cong a₁≈a₂ a₃≈a₄ (a₁≼a₃ , a₁̷≈a₃) =
( ≼-cong a₁≈a₂ a₃≈a₄ a₁≼a₃
, λ a₂≈a₄ a₁̷≈a₃ (≈-trans a₁≈a₂ (≈-trans a₂≈a₄ (≈-sym a₃≈a₄)))
)
record IsLattice {a} (A : Set a)
(_≈_ : A A Set a)
(_⊔_ : A A A)
(_⊓_ : A A A) : Set a where
field
joinSemilattice : IsSemilattice A _≈_ _⊔_
meetSemilattice : IsSemilattice A _≈_ _⊓_
absorb-⊔-⊓ : (x y : A) (x (x y)) x
absorb-⊓-⊔ : (x y : A) (x (x y)) x
open IsSemilattice joinSemilattice public
open IsSemilattice meetSemilattice public using () renaming
( ⊔-assoc to ⊓-assoc
; ⊔-comm to ⊓-comm
; ⊔-idemp to ⊓-idemp
; ≈-⊔-cong to ≈-⊓-cong
; _≼_ to _≽_
; _≺_ to _≻_
; ≼-refl to ≽-refl
)
FixedHeight : (h : ) Set a
FixedHeight h = Chain.Height (_≈_) ≈-equiv _≺_ ≺-cong h
record IsFiniteHeightLattice {a} (A : Set a)
(h : )
(_≈_ : A A Set a)
(_⊔_ : A A A)
(_⊓_ : A A A) : Set (lsuc a) where
field
isLattice : IsLattice A _≈_ _⊔_ _⊓_
open IsLattice isLattice public
field
fixedHeight : FixedHeight h
module _ {a b} {A : Set a} {B : Set b}
(_≼₁_ : A A Set a) (_≼₂_ : B B Set b) where
Monotonic : (A B) Set (a ⊔ℓ b)
Monotonic f = {a₁ a₂ : A} a₁ ≼₁ a₂ f a₁ ≼₂ f a₂
module ChainMapping {a b} {A : Set a} {B : Set b}
{_≈₁_ : A A Set a} {_≈₂_ : B B Set b}
{_⊔₁_ : A A A} {_⊔₂_ : B B B}
(slA : IsSemilattice A _≈₁_ _⊔₁_) (slB : IsSemilattice B _≈₂_ _⊔₂_) where
open IsSemilattice slA renaming (_≼_ to _≼₁_; _≺_ to _≺₁_; ≈-equiv to ≈₁-equiv; ≺-cong to ≺₁-cong)
open IsSemilattice slB renaming (_≼_ to _≼₂_; _≺_ to _≺₂_; ≈-equiv to ≈₂-equiv; ≺-cong to ≺₂-cong)
open Chain _≈₁_ ≈₁-equiv _≺₁_ ≺₁-cong using () renaming (Chain to Chain₁; step to step₁; done to done₁)
open Chain _≈₂_ ≈₂-equiv _≺₂_ ≺₂-cong using () renaming (Chain to Chain₂; step to step₂; done to done₂)
Chain-map : (f : A B)
Monotonic _≼₁_ _≼₂_ f
Injective _≈₁_ _≈₂_ f
f Preserves _≈₁_ _≈₂_
{a₁ a₂ : A} {n : } Chain₁ a₁ a₂ n Chain₂ (f a₁) (f a₂) n
Chain-map f Monotonicᶠ Injectiveᶠ Preservesᶠ (done₁ a₁≈a₂) =
done₂ (Preservesᶠ a₁≈a₂)
Chain-map f Monotonicᶠ Injectiveᶠ Preservesᶠ (step₁ (a₁≼₁a , a₁̷≈₁a) a≈₁a' a'a₂) =
let fa₁≺₂fa = (Monotonicᶠ a₁≼₁a , λ fa₁≈₂fa a₁̷≈₁a (Injectiveᶠ fa₁≈₂fa))
fa≈fa' = Preservesᶠ a≈₁a'
in step₂ fa₁≺₂fa fa≈fa' (Chain-map f Monotonicᶠ Injectiveᶠ Preservesᶠ a'a₂)
record Semilattice {a} (A : Set a) : Set (lsuc a) where
field
_≈_ : A A Set a
_⊔_ : A A A
isSemilattice : IsSemilattice A _≈_ _⊔_
open IsSemilattice isSemilattice public
record Lattice {a} (A : Set a) : Set (lsuc a) where
field
_≈_ : A A Set a
_⊔_ : A A A
_⊓_ : A A A
isLattice : IsLattice A _≈_ _⊔_ _⊓_
open IsLattice isLattice public