Move the product instances into its own file

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>
This commit is contained in:
Danila Fedorin 2023-09-23 16:34:30 -07:00
parent 8eaec3facd
commit 6cd37a212f
3 changed files with 168 additions and 176 deletions

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@ -9,29 +9,3 @@ record IsEquivalence {a} (A : Set a) (_≈_ : A → A → Set a) : Set a where
≈-refl : {a : A} a a
≈-sym : {a b : A} a b b a
≈-trans : {a b c : A} a b b c a c
module IsEquivalenceInstances where
module ForProd {a} {A B : Set a}
(_≈₁_ : A A Set a) (_≈₂_ : B B Set a)
(eA : IsEquivalence A _≈₁_) (eB : IsEquivalence B _≈₂_) where
infix 4 _≈_
_≈_ : A × B A × B Set a
(a₁ , b₁) (a₂ , b₂) = (a₁ ≈₁ a₂) × (b₁ ≈₂ b₂)
ProdEquivalence : IsEquivalence (A × B) _≈_
ProdEquivalence = record
{ ≈-refl = λ {p}
( IsEquivalence.≈-refl eA
, IsEquivalence.≈-refl eB
)
; ≈-sym = λ {p₁} {p₂} (a₁≈a₂ , b₁≈b₂)
( IsEquivalence.≈-sym eA a₁≈a₂
, IsEquivalence.≈-sym eB b₁≈b₂
)
; ≈-trans = λ {p₁} {p₂} {p₃} (a₁≈a₂ , b₁≈b₂) (a₂≈a₃ , b₂≈b₃)
( IsEquivalence.≈-trans eA a₁≈a₂ a₂≈a₃
, IsEquivalence.≈-trans eB b₁≈b₂ b₂≈b₃
)
}

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@ -6,7 +6,6 @@ import Chain
import Data.Nat.Properties as NatProps
open import Relation.Binary.PropositionalEquality as Eq using (_≡_; sym; subst)
open Eq.≡-Reasoning using (begin_; _≡⟨⟩_; step-≡; _∎)
open import Relation.Binary.Definitions
open import Relation.Binary.Core using (_Preserves_⟶_ )
open import Relation.Nullary using (Dec; ¬_; yes; no)
open import Data.Nat as Nat using (; _≤_; _+_; suc)
@ -142,152 +141,3 @@ record Lattice {a} (A : Set a) : Set (lsuc a) where
isLattice : IsLattice A _≈_ _⊔_ _⊓_
open IsLattice isLattice public
module IsSemilatticeInstances where
module ForProd {a} {A B : Set a}
(_≈₁_ : A A Set a) (_≈₂_ : B B Set a)
(_⊔₁_ : A A A) (_⊔₂_ : B B B)
(sA : IsSemilattice A _≈₁_ _⊔₁_) (sB : IsSemilattice B _≈₂_ _⊔₂_) where
open Eq
open Data.Product
module ProdEquiv = IsEquivalenceInstances.ForProd _≈₁_ _≈₂_ (IsSemilattice.≈-equiv sA) (IsSemilattice.≈-equiv sB)
open ProdEquiv using (_≈_) public
infixl 20 _⊔_
_⊔_ : A × B A × B A × B
(a₁ , b₁) (a₂ , b₂) = (a₁ ⊔₁ a₂ , b₁ ⊔₂ b₂)
ProdIsSemilattice : IsSemilattice (A × B) _≈_ _⊔_
ProdIsSemilattice = record
{ ≈-equiv = ProdEquiv.ProdEquivalence
; ≈-⊔-cong = λ (a₁≈a₂ , b₁≈b₂) (a₃≈a₄ , b₃≈b₄)
( IsSemilattice.≈-⊔-cong sA a₁≈a₂ a₃≈a₄
, IsSemilattice.≈-⊔-cong sB b₁≈b₂ b₃≈b₄
)
; ⊔-assoc = λ (a₁ , b₁) (a₂ , b₂) (a₃ , b₃)
( IsSemilattice.⊔-assoc sA a₁ a₂ a₃
, IsSemilattice.⊔-assoc sB b₁ b₂ b₃
)
; ⊔-comm = λ (a₁ , b₁) (a₂ , b₂)
( IsSemilattice.⊔-comm sA a₁ a₂
, IsSemilattice.⊔-comm sB b₁ b₂
)
; ⊔-idemp = λ (a , b)
( IsSemilattice.⊔-idemp sA a
, IsSemilattice.⊔-idemp sB b
)
}
module IsLatticeInstances where
module ForProd {a} {A B : Set a}
(_≈₁_ : A A Set a) (_≈₂_ : B B Set a)
(_⊔₁_ : A A A) (_⊓₁_ : A A A)
(_⊔₂_ : B B B) (_⊓₂_ : B B B)
(lA : IsLattice A _≈₁_ _⊔₁_ _⊓₁_) (lB : IsLattice B _≈₂_ _⊔₂_ _⊓₂_) where
module ProdJoin = IsSemilatticeInstances.ForProd _≈₁_ _≈₂_ _⊔₁_ _⊔₂_ (IsLattice.joinSemilattice lA) (IsLattice.joinSemilattice lB)
open ProdJoin using (_⊔_; _≈_) public
module ProdMeet = IsSemilatticeInstances.ForProd _≈₁_ _≈₂_ _⊓₁_ _⊓₂_ (IsLattice.meetSemilattice lA) (IsLattice.meetSemilattice lB)
open ProdMeet using () renaming (_⊔_ to _⊓_) public
ProdIsLattice : IsLattice (A × B) _≈_ _⊔_ _⊓_
ProdIsLattice = record
{ joinSemilattice = ProdJoin.ProdIsSemilattice
; meetSemilattice = ProdMeet.ProdIsSemilattice
; absorb-⊔-⊓ = λ (a₁ , b₁) (a₂ , b₂)
( IsLattice.absorb-⊔-⊓ lA a₁ a₂
, IsLattice.absorb-⊔-⊓ lB b₁ b₂
)
; absorb-⊓-⊔ = λ (a₁ , b₁) (a₂ , b₂)
( IsLattice.absorb-⊓-⊔ lA a₁ a₂
, IsLattice.absorb-⊓-⊔ lB b₁ b₂
)
}
module IsFiniteHeightLatticeInstances where
module ForProd {a} {A B : Set a}
(_≈₁_ : A A Set a) (_≈₂_ : B B Set a)
(≈₁-dec : IsDecidable _≈₁_) (≈₂-dec : IsDecidable _≈₂_)
(_⊔₁_ : A A A) (_⊓₁_ : A A A)
(_⊔₂_ : B B B) (_⊓₂_ : B B B)
(h₁ h₂ : )
(lA : IsFiniteHeightLattice A h₁ _≈₁_ _⊔₁_ _⊓₁_) (lB : IsFiniteHeightLattice B h₂ _≈₂_ _⊔₂_ _⊓₂_) where
open NatProps
module ProdLattice = IsLatticeInstances.ForProd _≈₁_ _≈₂_ _⊔₁_ _⊓₁_ _⊔₂_ _⊓₂_ (IsFiniteHeightLattice.isLattice lA) (IsFiniteHeightLattice.isLattice lB)
open ProdLattice using (_⊔_; _⊓_; _≈_) public
open IsLattice ProdLattice.ProdIsLattice using (_≼_; _≺_; ≺-cong; ≈-equiv)
open IsFiniteHeightLattice lA using () renaming (⊔-idemp to ⊔₁-idemp; _≼_ to _≼₁_; ≈-equiv to ≈₁-equiv; ≈-refl to ≈₁-refl; ≈-trans to ≈₁-trans; ≈-sym to ≈₁-sym; _≺_ to _≺₁_; ≺-cong to ≺₁-cong)
open IsFiniteHeightLattice lB using () renaming (⊔-idemp to ⊔₂-idemp; _≼_ to _≼₂_; ≈-equiv to ≈₂-equiv; ≈-refl to ≈₂-refl; ≈-trans to ≈₂-trans; ≈-sym to ≈₂-sym; _≺_ to _≺₂_; ≺-cong to ≺₂-cong)
module ChainMapping = ChainMapping (IsFiniteHeightLattice.joinSemilattice lA) (IsLattice.joinSemilattice ProdLattice.ProdIsLattice)
module ChainMapping = ChainMapping (IsFiniteHeightLattice.joinSemilattice lB) (IsLattice.joinSemilattice ProdLattice.ProdIsLattice)
module ChainA = Chain _≈₁_ ≈₁-equiv _≺₁_ ≺₁-cong
module ChainB = Chain _≈₂_ ≈₂-equiv _≺₂_ ≺₂-cong
module ProdChain = Chain _≈_ ≈-equiv _≺_ ≺-cong
open ChainA using () renaming (Chain to Chain₁; done to done₁; step to step₁; Chain-≈-cong₁ to Chain₁-≈-cong₁)
open ChainB using () renaming (Chain to Chain₂; done to done₂; step to step₂; Chain-≈-cong₁ to Chain₂-≈-cong₁)
open ProdChain using (Chain; concat; done; step)
private
a,∙-Monotonic : (a : A) Monotonic _≼₂_ _≼_ (λ b (a , b))
a,∙-Monotonic a {b₁} {b₂} (b , b₁⊔b≈b₂) = ((a , b) , (⊔₁-idemp a , b₁⊔b≈b₂))
a,∙-Preserves-≈₂ : (a : A) (λ b (a , b)) Preserves _≈₂_ _≈_
a,∙-Preserves-≈₂ a {b₁} {b₂} b₁≈b₂ = (≈₁-refl , b₁≈b₂)
∙,b-Monotonic : (b : B) Monotonic _≼₁_ _≼_ (λ a (a , b))
∙,b-Monotonic b {a₁} {a₂} (a , a₁⊔a≈a₂) = ((a , b) , (a₁⊔a≈a₂ , ⊔₂-idemp b))
∙,b-Preserves-≈₁ : (b : B) (λ a (a , b)) Preserves _≈₁_ _≈_
∙,b-Preserves-≈₁ b {a₁} {a₂} a₁≈a₂ = (a₁≈a₂ , ≈₂-refl)
amin : A
amin = proj₁ (proj₁ (proj₁ (IsFiniteHeightLattice.fixedHeight lA)))
amax : A
amax = proj₂ (proj₁ (proj₁ (IsFiniteHeightLattice.fixedHeight lA)))
bmin : B
bmin = proj₁ (proj₁ (proj₁ (IsFiniteHeightLattice.fixedHeight lB)))
bmax : B
bmax = proj₂ (proj₁ (proj₁ (IsFiniteHeightLattice.fixedHeight lB)))
unzip : {a₁ a₂ : A} {b₁ b₂ : B} {n : } Chain (a₁ , b₁) (a₂ , b₂) n Σ ( × ) (λ (n₁ , n₂) ((Chain₁ a₁ a₂ n₁ × Chain₂ b₁ b₂ n₂) × (n n₁ + n₂)))
unzip (done (a₁≈a₂ , b₁≈b₂)) = ((0 , 0) , ((done₁ a₁≈a₂ , done₂ b₁≈b₂) , ≤-refl))
unzip {a₁} {a₂} {b₁} {b₂} {n} (step {(a₁ , b₁)} {(a , b)} (((d₁ , d₂) , (a₁⊔d₁≈a , b₁⊔d₂≈b)) , a₁b₁̷≈ab) (a≈a' , b≈b') a'b'a₂b₂)
with ≈₁-dec a₁ a | ≈₂-dec b₁ b | unzip a'b'a₂b₂
... | yes a₁≈a | yes b₁≈b | ((n₁ , n₂) , ((c₁ , c₂) , n≤n₁+n₂)) = absurd (a₁b₁̷≈ab (a₁≈a , b₁≈b))
... | no a₁̷≈a | yes b₁≈b | ((n₁ , n₂) , ((c₁ , c₂) , n≤n₁+n₂)) =
((suc n₁ , n₂) , ((step₁ ((d₁ , a₁⊔d₁≈a) , a₁̷≈a) a≈a' c₁ , Chain₂-≈-cong₁ (≈₂-sym (≈₂-trans b₁≈b b≈b')) c₂), +-monoʳ-≤ 1 (n≤n₁+n₂)))
... | yes a₁≈a | no b₁̷≈b | ((n₁ , n₂) , ((c₁ , c₂) , n≤n₁+n₂)) =
((n₁ , suc n₂) , ( (Chain₁-≈-cong₁ (≈₁-sym (≈₁-trans a₁≈a a≈a')) c₁ , step₂ ((d₂ , b₁⊔d₂≈b) , b₁̷≈b) b≈b' c₂)
, subst (n ≤_) (sym (+-suc n₁ n₂)) (+-monoʳ-≤ 1 n≤n₁+n₂)
))
... | no a₁̷≈a | no b₁̷≈b | ((n₁ , n₂) , ((c₁ , c₂) , n≤n₁+n₂)) =
((suc n₁ , suc n₂) , ( (step₁ ((d₁ , a₁⊔d₁≈a) , a₁̷≈a) a≈a' c₁ , step₂ ((d₂ , b₁⊔d₂≈b) , b₁̷≈b) b≈b' c₂)
, ≤-stepsˡ 1 (subst (n ≤_) (sym (+-suc n₁ n₂)) (+-monoʳ-≤ 1 n≤n₁+n₂))
))
ProdIsFiniteHeightLattice : IsFiniteHeightLattice (A × B) (h₁ + h₂) _≈_ _⊔_ _⊓_
ProdIsFiniteHeightLattice = record
{ isLattice = ProdLattice.ProdIsLattice
; fixedHeight =
( ( ((amin , bmin) , (amax , bmax))
, concat
(ChainMapping₁.Chain-map (λ a (a , bmin)) (∙,b-Monotonic _) proj₁ (∙,b-Preserves-≈₁ _) (proj₂ (proj₁ (IsFiniteHeightLattice.fixedHeight lA))))
(ChainMapping₂.Chain-map (λ b (amax , b)) (a,∙-Monotonic _) proj₂ (a,∙-Preserves-≈₂ _) (proj₂ (proj₁ (IsFiniteHeightLattice.fixedHeight lB))))
)
, λ a₁b₁a₂b₂ let ((n₁ , n₂) , ((a₁a₂ , b₁b₂) , n≤n₁+n₂)) = unzip a₁b₁a₂b₂
in ≤-trans n≤n₁+n₂ (+-mono-≤ (proj₂ (IsFiniteHeightLattice.fixedHeight lA) a₁a₂)
(proj₂ (IsFiniteHeightLattice.fixedHeight lB) b₁b₂))
)
}

168
Lattice/Prod.agda Normal file
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@ -0,0 +1,168 @@
open import Lattice
module Lattice.Prod {a} {A B : Set a}
(_≈₁_ : A A Set a) (_≈₂_ : B B Set a)
(_⊔₁_ : A A A) (_⊔₂_ : B B B)
(_⊓₁_ : A A A) (_⊓₂_ : B B B)
(lA : IsLattice A _≈₁_ _⊔₁_ _⊓₁_) (lB : IsLattice B _≈₂_ _⊔₂_ _⊓₂_) where
open import Data.Nat using (; _≤_; _+_; suc)
open import Data.Product using (_×_; Σ; _,_; proj₁; proj₂)
open import Equivalence
open import Relation.Binary.Core using (_Preserves_⟶_ )
open import Relation.Binary.Definitions
open import Relation.Binary.PropositionalEquality using (sym; subst)
open import Relation.Nullary using (¬_; yes; no)
import Chain
open IsLattice lA using () renaming
( ≈-equiv to ≈₁-equiv; ≈-refl to ≈₁-refl; ≈-sym to ≈₁-sym; ≈-trans to ≈₁-trans
; joinSemilattice to joinSemilattice₁
; meetSemilattice to meetSemilattice₁
; FixedHeight to FixedHeight₁
; ⊔-idemp to ⊔₁-idemp
; _≼_ to _≼₁_; _≺_ to _≺₁_
; ≺-cong to ≺₁-cong
)
open IsLattice lB using () renaming
( ≈-equiv to ≈₂-equiv; ≈-refl to ≈₂-refl; ≈-sym to ≈₂-sym; ≈-trans to ≈₂-trans
; joinSemilattice to joinSemilattice₂
; meetSemilattice to meetSemilattice₂
; FixedHeight to FixedHeight₂
; ⊔-idemp to ⊔₂-idemp
; _≼_ to _≼₂_; _≺_ to _≺₂_
; ≺-cong to ≺₂-cong
)
_≈_ : A × B A × B Set a
(a₁ , b₁) (a₂ , b₂) = (a₁ ≈₁ a₂) × (b₁ ≈₂ b₂)
≈-equiv : IsEquivalence (A × B) _≈_
≈-equiv = record
{ ≈-refl = λ {p} (≈₁-refl , ≈₂-refl)
; ≈-sym = λ {p₁} {p₂} (a₁≈a₂ , b₁≈b₂) (≈₁-sym a₁≈a₂ , ≈₂-sym b₁≈b₂)
; ≈-trans = λ {p₁} {p₂} {p₃} (a₁≈a₂ , b₁≈b₂) (a₂≈a₃ , b₂≈b₃)
( ≈₁-trans a₁≈a₂ a₂≈a₃ , ≈₂-trans b₁≈b₂ b₂≈b₃ )
}
_⊔_ : A × B A × B A × B
(a₁ , b₁) (a₂ , b₂) = (a₁ ⊔₁ a₂ , b₁ ⊔₂ b₂)
_⊓_ : A × B A × B A × B
(a₁ , b₁) (a₂ , b₂) = (a₁ ⊓₁ a₂ , b₁ ⊓₂ b₂)
private module ProdIsSemilattice (f₁ : A A A) (f₂ : B B B) (sA : IsSemilattice A _≈₁_ f₁) (sB : IsSemilattice B _≈₂_ f₂) where
isSemilattice : IsSemilattice (A × B) _≈_ (λ (a₁ , b₁) (a₂ , b₂) (f₁ a₁ a₂ , f₂ b₁ b₂))
isSemilattice = record
{ ≈-equiv = ≈-equiv
; ≈-⊔-cong = λ (a₁≈a₂ , b₁≈b₂) (a₃≈a₄ , b₃≈b₄)
( IsSemilattice.≈-⊔-cong sA a₁≈a₂ a₃≈a₄
, IsSemilattice.≈-⊔-cong sB b₁≈b₂ b₃≈b₄
)
; ⊔-assoc = λ (a₁ , b₁) (a₂ , b₂) (a₃ , b₃)
( IsSemilattice.⊔-assoc sA a₁ a₂ a₃
, IsSemilattice.⊔-assoc sB b₁ b₂ b₃
)
; ⊔-comm = λ (a₁ , b₁) (a₂ , b₂)
( IsSemilattice.⊔-comm sA a₁ a₂
, IsSemilattice.⊔-comm sB b₁ b₂
)
; ⊔-idemp = λ (a , b)
( IsSemilattice.⊔-idemp sA a
, IsSemilattice.⊔-idemp sB b
)
}
isJoinSemilattice : IsSemilattice (A × B) _≈_ _⊔_
isJoinSemilattice = ProdIsSemilattice.isSemilattice _⊔₁_ _⊔₂_ joinSemilattice₁ joinSemilattice₂
isMeetSemilattice : IsSemilattice (A × B) _≈_ _⊓_
isMeetSemilattice = ProdIsSemilattice.isSemilattice _⊓₁_ _⊓₂_ meetSemilattice₁ meetSemilattice₂
isLattice : IsLattice (A × B) _≈_ _⊔_ _⊓_
isLattice = record
{ joinSemilattice = isJoinSemilattice
; meetSemilattice = isMeetSemilattice
; absorb-⊔-⊓ = λ (a₁ , b₁) (a₂ , b₂)
( IsLattice.absorb-⊔-⊓ lA a₁ a₂
, IsLattice.absorb-⊔-⊓ lB b₁ b₂
)
; absorb-⊓-⊔ = λ (a₁ , b₁) (a₂ , b₂)
( IsLattice.absorb-⊓-⊔ lA a₁ a₂
, IsLattice.absorb-⊓-⊔ lB b₁ b₂
)
}
module _ (≈₁-dec : IsDecidable _≈₁_) (≈₂-dec : IsDecidable _≈₂_)
(h₁ h₂ : )
(fhA : FixedHeight₁ h₁) (fhB : FixedHeight₂ h₂) where
open import Data.Nat.Properties
open IsLattice isLattice using (_≼_; _≺_; ≺-cong)
module ChainMapping = ChainMapping joinSemilattice₁ isJoinSemilattice
module ChainMapping = ChainMapping joinSemilattice₂ isJoinSemilattice
module ChainA = Chain _≈₁_ ≈₁-equiv _≺₁_ ≺₁-cong
module ChainB = Chain _≈₂_ ≈₂-equiv _≺₂_ ≺₂-cong
module ProdChain = Chain _≈_ ≈-equiv _≺_ ≺-cong
open ChainA using () renaming (Chain to Chain₁; done to done₁; step to step₁; Chain-≈-cong₁ to Chain₁-≈-cong₁)
open ChainB using () renaming (Chain to Chain₂; done to done₂; step to step₂; Chain-≈-cong₁ to Chain₂-≈-cong₁)
open ProdChain using (Chain; concat; done; step)
private
a,∙-Monotonic : (a : A) Monotonic _≼₂_ _≼_ (λ b (a , b))
a,∙-Monotonic a {b₁} {b₂} (b , b₁⊔b≈b₂) = ((a , b) , (⊔₁-idemp a , b₁⊔b≈b₂))
a,∙-Preserves-≈₂ : (a : A) (λ b (a , b)) Preserves _≈₂_ _≈_
a,∙-Preserves-≈₂ a {b₁} {b₂} b₁≈b₂ = (≈₁-refl , b₁≈b₂)
∙,b-Monotonic : (b : B) Monotonic _≼₁_ _≼_ (λ a (a , b))
∙,b-Monotonic b {a₁} {a₂} (a , a₁⊔a≈a₂) = ((a , b) , (a₁⊔a≈a₂ , ⊔₂-idemp b))
∙,b-Preserves-≈₁ : (b : B) (λ a (a , b)) Preserves _≈₁_ _≈_
∙,b-Preserves-≈₁ b {a₁} {a₂} a₁≈a₂ = (a₁≈a₂ , ≈₂-refl)
amin : A
amin = proj₁ (proj₁ (proj₁ fhA))
amax : A
amax = proj₂ (proj₁ (proj₁ fhA))
bmin : B
bmin = proj₁ (proj₁ (proj₁ fhB))
bmax : B
bmax = proj₂ (proj₁ (proj₁ fhB))
unzip : {a₁ a₂ : A} {b₁ b₂ : B} {n : } Chain (a₁ , b₁) (a₂ , b₂) n Σ ( × ) (λ (n₁ , n₂) ((Chain₁ a₁ a₂ n₁ × Chain₂ b₁ b₂ n₂) × (n n₁ + n₂)))
unzip (done (a₁≈a₂ , b₁≈b₂)) = ((0 , 0) , ((done₁ a₁≈a₂ , done₂ b₁≈b₂) , ≤-refl))
unzip {a₁} {a₂} {b₁} {b₂} {n} (step {(a₁ , b₁)} {(a , b)} (((d₁ , d₂) , (a₁⊔d₁≈a , b₁⊔d₂≈b)) , a₁b₁̷≈ab) (a≈a' , b≈b') a'b'a₂b₂)
with ≈₁-dec a₁ a | ≈₂-dec b₁ b | unzip a'b'a₂b₂
... | yes a₁≈a | yes b₁≈b | ((n₁ , n₂) , ((c₁ , c₂) , n≤n₁+n₂)) = absurd (a₁b₁̷≈ab (a₁≈a , b₁≈b))
... | no a₁̷≈a | yes b₁≈b | ((n₁ , n₂) , ((c₁ , c₂) , n≤n₁+n₂)) =
((suc n₁ , n₂) , ((step₁ ((d₁ , a₁⊔d₁≈a) , a₁̷≈a) a≈a' c₁ , Chain₂-≈-cong₁ (≈₂-sym (≈₂-trans b₁≈b b≈b')) c₂), +-monoʳ-≤ 1 (n≤n₁+n₂)))
... | yes a₁≈a | no b₁̷≈b | ((n₁ , n₂) , ((c₁ , c₂) , n≤n₁+n₂)) =
((n₁ , suc n₂) , ( (Chain₁-≈-cong₁ (≈₁-sym (≈₁-trans a₁≈a a≈a')) c₁ , step₂ ((d₂ , b₁⊔d₂≈b) , b₁̷≈b) b≈b' c₂)
, subst (n ≤_) (sym (+-suc n₁ n₂)) (+-monoʳ-≤ 1 n≤n₁+n₂)
))
... | no a₁̷≈a | no b₁̷≈b | ((n₁ , n₂) , ((c₁ , c₂) , n≤n₁+n₂)) =
((suc n₁ , suc n₂) , ( (step₁ ((d₁ , a₁⊔d₁≈a) , a₁̷≈a) a≈a' c₁ , step₂ ((d₂ , b₁⊔d₂≈b) , b₁̷≈b) b≈b' c₂)
, ≤-stepsˡ 1 (subst (n ≤_) (sym (+-suc n₁ n₂)) (+-monoʳ-≤ 1 n≤n₁+n₂))
))
isFiniteHeightLattice : IsFiniteHeightLattice (A × B) (h₁ + h₂) _≈_ _⊔_ _⊓_
isFiniteHeightLattice = record
{ isLattice = isLattice
; fixedHeight =
( ( ((amin , bmin) , (amax , bmax))
, concat
(ChainMapping₁.Chain-map (λ a (a , bmin)) (∙,b-Monotonic _) proj₁ (∙,b-Preserves-≈₁ _) (proj₂ (proj₁ fhA)))
(ChainMapping₂.Chain-map (λ b (amax , b)) (a,∙-Monotonic _) proj₂ (a,∙-Preserves-≈₂ _) (proj₂ (proj₁ fhB)))
)
, λ a₁b₁a₂b₂ let ((n₁ , n₂) , ((a₁a₂ , b₁b₂) , n≤n₁+n₂)) = unzip a₁b₁a₂b₂
in ≤-trans n≤n₁+n₂ (+-mono-≤ (proj₂ fhA a₁a₂) (proj₂ fhB b₁b₂))
)
}