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Factor the Semilattice instances for Nat into their own module

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Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>
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Danila Fedorin
2023-07-14 19:59:07 -07:00
parent c9b514e9af
commit 1ee6682c1a
1 changed files with 69 additions and 64 deletions
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Lattice.agda
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@@ -106,20 +106,17 @@ module PreorderInstances where
_≼_ : A × B → A × B → Set a
(a₁ , b₁) ≼ (a₂ , b₂) = Preorder._≼_ pA a₁ a₂ × Preorder._≼_ pB b₁ b₂
ispA = Preorder.isPreorder pA
ispB = Preorder.isPreorder pB
≼-refl : {p : A × B} → p ≼ p
≼-refl {(a , b)} = (IsPreorder.≼-refl ispA {a}, IsPreorder.≼-refl ispB {b})
≼-refl {(a , b)} = (Preorder.≼-refl pA {a}, Preorder.≼-refl pB {b})
≼-trans : {p₁ p₂ p₃ : A × B} → p₁ ≼ p₂ → p₂ ≼ p₃ → p₁ ≼ p₃
≼-trans (a₁≼a₂ , b₁≼b₂) (a₂≼a₃ , b₂≼b₃) =
( IsPreorder.≼-trans ispA a₁≼a₂ a₂≼a₃
, IsPreorder.≼-trans ispB b₁≼b₂ b₂≼b₃
( Preorder.≼-trans pA a₁≼a₂ a₂≼a₃
, Preorder.≼-trans pB b₁≼b₂ b₂≼b₃
)
≼-antisym : {p₁ p₂ : A × B} → p₁ ≼ p₂ → p₂ ≼ p₁ → p₁ ≡ p₂
≼-antisym (a₁≼a₂ , b₁≼b₂) (a₂≼a₁ , b₂≼b₁) = cong₂ (_,_) (IsPreorder.≼-antisym ispA a₁≼a₂ a₂≼a₁) (IsPreorder.≼-antisym ispB b₁≼b₂ b₂≼b₁)
≼-antisym (a₁≼a₂ , b₁≼b₂) (a₂≼a₁ , b₂≼b₁) = cong₂ (_,_) (Preorder.≼-antisym pA a₁≼a₂ a₂≼a₁) (Preorder.≼-antisym pB b₁≼b₂ b₂≼b₁)
ProdPreorder : Preorder (A × B)
ProdPreorder = record
@@ -131,8 +128,8 @@ module PreorderInstances where
}
}
private module NatInstances where
module SemilatticeInstances where
module ForNat where
open Nat
open NatProps
open Eq
@@ -191,12 +188,20 @@ private module NatInstances where
}
}
private module NatInstances where
open Nat
open NatProps
open Eq
open SemilatticeInstances.ForNat
open Data.Product
private
minmax-absorb : {x y : ℕ} → x ⊓ (x ⊔ y) ≡ x
minmax-absorb {x} {y} = ≤-antisym x⊓x⊔y≤x (helper x⊓x≤x⊓x⊔y (⊓-idem x))
where
x⊓x⊔y≤x = min-bound₁ {x} {x ⊔ y} {x ⊓ (x ⊔ y)} refl
x⊓x≤x⊓x⊔y = ⊓-mono-≤ {x} {x} ≤-refl (max-bound₁ {x} {y} {x ⊔ y} refl)
x⊓x⊔y≤x = proj₁ (Semilattice.⊔-bound NatMinSemilattice x (x ⊔ y) (x ⊓ (x ⊔ y)) refl)
x⊓x≤x⊓x⊔y = ⊓-mono-≤ {x} {x} ≤-refl (proj₁ (Semilattice.⊔-bound NatMaxSemilattice x y (x ⊔ y) refl))
-- >:(
helper : x ⊓ x ≤ x ⊓ (x ⊔ y) → x ⊓ x ≡ x → x ≤ x ⊓ (x ⊔ y)
@@ -205,8 +210,8 @@ private module NatInstances where
maxmin-absorb : {x y : ℕ} → x ⊔ (x ⊓ y) ≡ x
maxmin-absorb {x} {y} = ≤-antisym (helper x⊔x⊓y≤x⊔x (⊔-idem x)) x≤x⊔x⊓y
where
x≤x⊔x⊓y = max-bound₁ {x} {x ⊓ y} {x ⊔ (x ⊓ y)} refl
x⊔x⊓y≤x⊔x = ⊔-mono-≤ {x} {x} ≤-refl (min-bound₁ {x} {y} {x ⊓ y} refl)
x≤x⊔x⊓y = proj₁ (Semilattice.⊔-bound NatMaxSemilattice x (x ⊓ y) (x ⊔ (x ⊓ y)) refl)
x⊔x⊓y≤x⊔x = ⊔-mono-≤ {x} {x} ≤-refl (proj₁ (Semilattice.⊔-bound NatMinSemilattice x y (x ⊓ y) refl))
-- >:(
helper : x ⊔ (x ⊓ y) ≤ x ⊔ x → x ⊔ x ≡ x → x ⊔ (x ⊓ y) ≤ x