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-rw-r--r--Functor/Instance/Cospan/Embed.agda103
-rw-r--r--Functor/Instance/Cospan/Stack.agda96
-rw-r--r--Functor/Instance/Decorate.agda31
-rw-r--r--Functor/Instance/DecoratedCospan/Embed.agda10
-rw-r--r--Functor/Instance/DecoratedCospan/Stack.agda41
-rw-r--r--Functor/Instance/Endo/List.agda15
-rw-r--r--Functor/Instance/List.agda67
-rw-r--r--Functor/Instance/Monoidalize.agda43
-rw-r--r--Functor/Instance/Multiset.agda72
-rw-r--r--Functor/Instance/Nat/Circ.agda56
-rw-r--r--Functor/Instance/Nat/Edge.agda60
-rw-r--r--Functor/Instance/Nat/Preimage.agda65
-rw-r--r--Functor/Instance/Nat/Pull.agda81
-rw-r--r--Functor/Instance/Nat/Push.agda79
-rw-r--r--Functor/Instance/Nat/System.agda110
15 files changed, 786 insertions, 143 deletions
diff --git a/Functor/Instance/Cospan/Embed.agda b/Functor/Instance/Cospan/Embed.agda
index 77f0361..6dbc04a 100644
--- a/Functor/Instance/Cospan/Embed.agda
+++ b/Functor/Instance/Cospan/Embed.agda
@@ -1,4 +1,5 @@
{-# OPTIONS --without-K --safe #-}
+{-# OPTIONS --hidden-argument-puns #-}
open import Category.Cocomplete.Finitely.Bundle using (FinitelyCocompleteCategory)
@@ -14,9 +15,10 @@ open import Categories.Category using (_[_,_]; _[_∘_]; _[_≈_])
open import Categories.Category.Core using (Category)
open import Categories.Functor.Core using (Functor)
open import Category.Instance.Cospans 𝒞 using (Cospans)
+open import Category.Diagram.Cospan 𝒞 using (cospan)
open import Data.Product.Base using (_,_)
open import Function.Base using (id)
-open import Functor.Instance.Cospan.Stack using (⊗)
+open import Functor.Instance.Cospan.Stack 𝒞 using (⊗)
module 𝒞 = FinitelyCocompleteCategory 𝒞
module Cospans = Category Cospans
@@ -28,24 +30,26 @@ open Morphism U using (module ≅; _≅_)
open PushoutProperties U using (up-to-iso)
open Pushout′ U using (pushout-id-g; pushout-f-id)
-L₁ : {A B : 𝒞.Obj} → U [ A , B ] → Cospans [ A , B ]
-L₁ f = record
- { f₁ = f
- ; f₂ = 𝒞.id
- }
+private
+ variable
+ A B C : 𝒞.Obj
+ W X Y Z : 𝒞.Obj
+
+L₁ : U [ A , B ] → Cospans [ A , B ]
+L₁ f = cospan f 𝒞.id
-L-identity : {A : 𝒞.Obj} → L₁ 𝒞.id ≈ Cospans.id {A}
+L-identity : L₁ 𝒞.id ≈ Cospans.id {A}
L-identity = record
{ ≅N = ≅.refl
- ; from∘f₁≈f₁′ = 𝒞.identity²
- ; from∘f₂≈f₂′ = 𝒞.identity²
+ ; from∘f₁≈f₁ = 𝒞.identity²
+ ; from∘f₂≈f₂ = 𝒞.identity²
}
-L-homomorphism : {X Y Z : 𝒞.Obj} {f : U [ X , Y ]} {g : U [ Y , Z ]} → L₁ (U [ g ∘ f ]) ≈ Cospans [ L₁ g ∘ L₁ f ]
+L-homomorphism : {f : U [ X , Y ]} {g : U [ Y , Z ]} → L₁ (U [ g ∘ f ]) ≈ Cospans [ L₁ g ∘ L₁ f ]
L-homomorphism {X} {Y} {Z} {f} {g} = record
{ ≅N = up-to-iso P′ P
- ; from∘f₁≈f₁′ = pullˡ (P′.universal∘i₁≈h₁ {eq = P.commute})
- ; from∘f₂≈f₂′ = P′.universal∘i₂≈h₂ {eq = P.commute} ○ sym 𝒞.identityʳ
+ ; from∘f₁≈f₁ = pullˡ (P′.universal∘i₁≈h₁ {eq = P.commute})
+ ; from∘f₂≈f₂ = P′.universal∘i₂≈h₂ {eq = P.commute} ○ sym 𝒞.identityʳ
}
where
open ⇒-Reasoning U
@@ -57,11 +61,11 @@ L-homomorphism {X} {Y} {Z} {f} {g} = record
module P = Pushout P
module P′ = Pushout P′
-L-resp-≈ : {A B : 𝒞.Obj} {f g : U [ A , B ]} → U [ f ≈ g ] → Cospans [ L₁ f ≈ L₁ g ]
+L-resp-≈ : {f g : U [ A , B ]} → U [ f ≈ g ] → Cospans [ L₁ f ≈ L₁ g ]
L-resp-≈ {A} {B} {f} {g} f≈g = record
{ ≅N = ≅.refl
- ; from∘f₁≈f₁′ = 𝒞.identityˡ ○ f≈g
- ; from∘f₂≈f₂′ = 𝒞.identity²
+ ; from∘f₁≈f₁ = 𝒞.identityˡ ○ f≈g
+ ; from∘f₂≈f₂ = 𝒞.identity²
}
where
open 𝒞.HomReasoning
@@ -75,24 +79,21 @@ L = record
; F-resp-≈ = L-resp-≈
}
-R₁ : {A B : 𝒞.Obj} → U [ B , A ] → Cospans [ A , B ]
-R₁ g = record
- { f₁ = 𝒞.id
- ; f₂ = g
- }
+R₁ : U [ B , A ] → Cospans [ A , B ]
+R₁ g = cospan 𝒞.id g
-R-identity : {A : 𝒞.Obj} → R₁ 𝒞.id ≈ Cospans.id {A}
+R-identity : R₁ 𝒞.id ≈ Cospans.id {A}
R-identity = record
{ ≅N = ≅.refl
- ; from∘f₁≈f₁′ = 𝒞.identity²
- ; from∘f₂≈f₂′ = 𝒞.identity²
+ ; from∘f₁≈f₁ = 𝒞.identity²
+ ; from∘f₂≈f₂ = 𝒞.identity²
}
-R-homomorphism : {X Y Z : 𝒞.Obj} {f : U [ Y , X ]} {g : U [ Z , Y ]} → R₁ (U [ f ∘ g ]) ≈ Cospans [ R₁ g ∘ R₁ f ]
-R-homomorphism {X} {Y} {Z} {f} {g} = record
+R-homomorphism : {f : U [ Y , X ]} {g : U [ Z , Y ]} → R₁ (U [ f ∘ g ]) ≈ Cospans [ R₁ g ∘ R₁ f ]
+R-homomorphism {f} {g} = record
{ ≅N = up-to-iso P′ P
- ; from∘f₁≈f₁′ = P′.universal∘i₁≈h₁ {eq = P.commute} ○ sym 𝒞.identityʳ
- ; from∘f₂≈f₂′ = pullˡ (P′.universal∘i₂≈h₂ {eq = P.commute})
+ ; from∘f₁≈f₁ = P′.universal∘i₁≈h₁ {eq = P.commute} ○ sym 𝒞.identityʳ
+ ; from∘f₂≈f₂ = pullˡ (P′.universal∘i₂≈h₂ {eq = P.commute})
}
where
open ⇒-Reasoning U
@@ -104,11 +105,11 @@ R-homomorphism {X} {Y} {Z} {f} {g} = record
module P = Pushout P
module P′ = Pushout P′
-R-resp-≈ : {A B : 𝒞.Obj} {f g : U [ A , B ]} → U [ f ≈ g ] → Cospans [ R₁ f ≈ R₁ g ]
-R-resp-≈ {A} {B} {f} {g} f≈g = record
+R-resp-≈ : {f g : U [ A , B ]} → U [ f ≈ g ] → Cospans [ R₁ f ≈ R₁ g ]
+R-resp-≈ {f} {g} f≈g = record
{ ≅N = ≅.refl
- ; from∘f₁≈f₁′ = 𝒞.identity²
- ; from∘f₂≈f₂′ = 𝒞.identityˡ ○ f≈g
+ ; from∘f₁≈f₁ = 𝒞.identity²
+ ; from∘f₂≈f₂ = 𝒞.identityˡ ○ f≈g
}
where
open 𝒞.HomReasoning
@@ -122,17 +123,11 @@ R = record
; F-resp-≈ = R-resp-≈
}
-B₁ : {A B C : 𝒞.Obj} → U [ A , C ] → U [ B , C ] → Cospans [ A , B ]
-B₁ f g = record
- { f₁ = f
- ; f₂ = g
- }
-
-B∘L : {W X Y Z : 𝒞.Obj} {f : U [ W , X ]} {g : U [ X , Y ]} {h : U [ Z , Y ]} → Cospans [ B₁ g h ∘ L₁ f ] ≈ B₁ (U [ g ∘ f ]) h
-B∘L {W} {X} {Y} {Z} {f} {g} {h} = record
+B∘L : {f : U [ W , X ]} {g : U [ X , Y ]} {h : U [ Z , Y ]} → Cospans [ cospan g h ∘ L₁ f ] ≈ cospan (U [ g ∘ f ]) h
+B∘L {f} {g} {h} = record
{ ≅N = up-to-iso P P′
- ; from∘f₁≈f₁′ = pullˡ (P.universal∘i₁≈h₁ {eq = P′.commute})
- ; from∘f₂≈f₂′ = pullˡ (P.universal∘i₂≈h₂ {eq = P′.commute}) ○ 𝒞.identityˡ
+ ; from∘f₁≈f₁ = pullˡ (P.universal∘i₁≈h₁ {eq = P′.commute})
+ ; from∘f₂≈f₂ = pullˡ (P.universal∘i₂≈h₂ {eq = P′.commute}) ○ 𝒞.identityˡ
}
where
open ⇒-Reasoning U
@@ -144,11 +139,11 @@ B∘L {W} {X} {Y} {Z} {f} {g} {h} = record
module P = Pushout P
module P′ = Pushout P′
-R∘B : {W X Y Z : 𝒞.Obj} {f : U [ W , X ]} {g : U [ Y , X ]} {h : U [ Z , Y ]} → Cospans [ R₁ h ∘ B₁ f g ] ≈ B₁ f (U [ g ∘ h ])
-R∘B {W} {X} {Y} {Z} {f} {g} {h} = record
+R∘B : {f : U [ W , X ]} {g : U [ Y , X ]} {h : U [ Z , Y ]} → Cospans [ R₁ h ∘ cospan f g ] ≈ cospan f (U [ g ∘ h ])
+R∘B {f} {g} {h} = record
{ ≅N = up-to-iso P P′
- ; from∘f₁≈f₁′ = pullˡ (P.universal∘i₁≈h₁ {eq = P′.commute}) ○ 𝒞.identityˡ
- ; from∘f₂≈f₂′ = pullˡ (P.universal∘i₂≈h₂ {eq = P′.commute})
+ ; from∘f₁≈f₁ = pullˡ (P.universal∘i₁≈h₁ {eq = P′.commute}) ○ 𝒞.identityˡ
+ ; from∘f₂≈f₂ = pullˡ (P.universal∘i₂≈h₂ {eq = P′.commute})
}
where
open ⇒-Reasoning U
@@ -164,20 +159,18 @@ module _ where
open _≅_
- ≅-L-R : ∀ {X Y : 𝒞.Obj} (X≅Y : X ≅ Y) → L₁ (to X≅Y) ≈ R₁ (from X≅Y)
- ≅-L-R {X} {Y} X≅Y = record
+ ≅-L-R : (X≅Y : X ≅ Y) → L₁ (to X≅Y) ≈ R₁ (from X≅Y)
+ ≅-L-R X≅Y = record
{ ≅N = X≅Y
- ; from∘f₁≈f₁′ = isoʳ X≅Y
- ; from∘f₂≈f₂′ = 𝒞.identityʳ
+ ; from∘f₁≈f₁ = isoʳ X≅Y
+ ; from∘f₂≈f₂ = 𝒞.identityʳ
}
-module ⊗ = Functor (⊗ 𝒞)
-
-L-resp-⊗ : {X Y X′ Y′ : 𝒞.Obj} {a : U [ X , X′ ]} {b : U [ Y , Y′ ]} → L₁ (a +₁ b) ≈ ⊗.₁ (L₁ a , L₁ b)
-L-resp-⊗ {X} {Y} {X′} {Y′} {a} {b} = record
+L-resp-⊗ : {a : U [ W , X ]} {b : U [ Y , Z ]} → L₁ (a +₁ b) ≈ ⊗.₁ (L₁ a , L₁ b)
+L-resp-⊗ {a} {b} = record
{ ≅N = ≅.refl
- ; from∘f₁≈f₁′ = 𝒞.identityˡ
- ; from∘f₂≈f₂′ = 𝒞.identityˡ ○ sym +-η ○ sym ([]-cong₂ identityʳ identityʳ)
+ ; from∘f₁≈f₁ = 𝒞.identityˡ
+ ; from∘f₂≈f₂ = 𝒞.identityˡ ○ sym +-η ○ sym ([]-cong₂ identityʳ identityʳ)
}
where
open 𝒞.HomReasoning
diff --git a/Functor/Instance/Cospan/Stack.agda b/Functor/Instance/Cospan/Stack.agda
index 03cca1f..b72219b 100644
--- a/Functor/Instance/Cospan/Stack.agda
+++ b/Functor/Instance/Cospan/Stack.agda
@@ -9,9 +9,11 @@ import Categories.Diagram.Pushout.Properties as PushoutProperties
import Categories.Morphism as Morphism
import Categories.Morphism.Reasoning as ⇒-Reasoning
-open import Categories.Category.Core using (Category)
+open import Categories.Category using (Category)
+open import Categories.Functor using (Functor)
open import Categories.Functor.Bifunctor using (Bifunctor)
-open import Category.Instance.Cospans 𝒞 using (Cospan; Cospans; Same; id-Cospan; compose)
+open import Category.Instance.Cospans 𝒞 using (Cospans)
+open import Category.Diagram.Cospan 𝒞 as Cospan using (Cospan; identity; compose; _⊗_)
open import Category.Instance.FinitelyCocompletes {o} {ℓ} {e} using () renaming (_×_ to _×′_)
open import Category.Cartesian.Instance.FinitelyCocompletes {o} {ℓ} {e} using (-+-; FinitelyCocompletes-CC)
open import Data.Product.Base using (Σ; _,_; _×_; proj₁; proj₂)
@@ -32,27 +34,19 @@ open DiagramPushout U×U using () renaming (Pushout to Pushout′)
open import Categories.Category.Monoidal.Utilities monoidal using (_⊗ᵢ_)
-together : {A A′ B B′ : Obj} → Cospan A B → Cospan A′ B′ → Cospan (A + A′) (B + B′)
-together A⇒B A⇒B′ = record
- { f₁ = f₁ A⇒B +₁ f₁ A⇒B′
- ; f₂ = f₂ A⇒B +₁ f₂ A⇒B′
- }
- where
- open Cospan
-
-id⊗id≈id : {A B : Obj} → Same (together (id-Cospan {A}) (id-Cospan {B})) (id-Cospan {A + B})
+id⊗id≈id : {A B : Obj} → identity {A} ⊗ identity {B} Cospan.≈ identity {A + B}
id⊗id≈id {A} {B} = record
{ ≅N = ≅.refl
- ; from∘f₁≈f₁′ = from∘f≈f′
- ; from∘f₂≈f₂′ = from∘f≈f′
+ ; from∘f₁≈f₁ = from∘f≈f
+ ; from∘f₂≈f₂ = from∘f≈f
}
where
open Morphism U using (module ≅)
open HomReasoning
open 𝒞 using (+-η; []-cong₂)
open coproduct {A} {B} using (i₁; i₂)
- from∘f≈f′ : id ∘ [ i₁ ∘ id , i₂ ∘ id ] 𝒞.≈ id
- from∘f≈f′ = begin
+ from∘f≈f : id ∘ [ i₁ ∘ id , i₂ ∘ id ] 𝒞.≈ id
+ from∘f≈f = begin
id ∘ [ i₁ ∘ id , i₂ ∘ id ] ≈⟨ identityˡ ⟩
[ i₁ ∘ id , i₂ ∘ id ] ≈⟨ []-cong₂ identityʳ identityʳ ⟩
[ i₁ , i₂ ] ≈⟨ +-η ⟩
@@ -64,14 +58,14 @@ homomorphism
→ (B⇒C : Cospan B C)
→ (A⇒B′ : Cospan A′ B′)
→ (B⇒C′ : Cospan B′ C′)
- → Same (together (compose A⇒B B⇒C) (compose A⇒B′ B⇒C′)) (compose (together A⇒B A⇒B′) (together B⇒C B⇒C′) )
+ → compose A⇒B B⇒C ⊗ compose A⇒B′ B⇒C′ Cospan.≈ compose (A⇒B ⊗ A⇒B′) (B⇒C ⊗ B⇒C′)
homomorphism A⇒B B⇒C A⇒B′ B⇒C′ = record
{ ≅N = ≅N
- ; from∘f₁≈f₁′ = from∘f₁≈f₁′
- ; from∘f₂≈f₂′ = from∘f₂≈f₂′
+ ; from∘f₁≈f₁ = from∘f₁≈f₁
+ ; from∘f₂≈f₂ = from∘f₂≈f₂
}
where
- open Cospan
+ open Cospan.Cospan
open Pushout
open HomReasoning
open ⇒-Reasoning U
@@ -89,56 +83,62 @@ homomorphism A⇒B B⇒C A⇒B′ B⇒C′ = record
P₃′ = IsPushout⇒Pushout (-+-.F-resp-pushout P₁×P₂.isPushout)
≅N : Q P₃′ ≅ Q P₃
≅N = up-to-iso P₃′ P₃
- from∘f₁≈f₁′ : from ≅N ∘ (f₁ (compose A⇒B B⇒C) +₁ f₁ (compose A⇒B′ B⇒C′)) ≈ f₁ (compose (together A⇒B A⇒B′) (together B⇒C B⇒C′))
- from∘f₁≈f₁′ = begin
+ from∘f₁≈f₁ : from ≅N ∘ (f₁ (compose A⇒B B⇒C) +₁ f₁ (compose A⇒B′ B⇒C′)) ≈ f₁ (compose (A⇒B ⊗ A⇒B′) (B⇒C ⊗ B⇒C′))
+ from∘f₁≈f₁ = begin
from ≅N ∘ (f₁ (compose A⇒B B⇒C) +₁ f₁ (compose A⇒B′ B⇒C′)) ≈⟨ Equiv.refl ⟩
from ≅N ∘ ((i₁ P₁ ∘ f₁ A⇒B) +₁ (i₁ P₂ ∘ f₁ A⇒B′)) ≈⟨ refl⟩∘⟨ +₁∘+₁ ⟨
from ≅N ∘ (i₁ P₁ +₁ i₁ P₂) ∘ (f₁ A⇒B +₁ f₁ A⇒B′) ≈⟨ Equiv.refl ⟩
- from ≅N ∘ i₁ P₃′ ∘ f₁ (together A⇒B A⇒B′) ≈⟨ pullˡ (universal∘i₁≈h₁ P₃′) ⟩
- i₁ P₃ ∘ f₁ (together A⇒B A⇒B′) ∎
- from∘f₂≈f₂′ : from ≅N ∘ (f₂ (compose A⇒B B⇒C) +₁ f₂ (compose A⇒B′ B⇒C′)) ≈ f₂ (compose (together A⇒B A⇒B′) (together B⇒C B⇒C′))
- from∘f₂≈f₂′ = begin
+ from ≅N ∘ i₁ P₃′ ∘ f₁ (A⇒B ⊗ A⇒B′) ≈⟨ pullˡ (universal∘i₁≈h₁ P₃′) ⟩
+ i₁ P₃ ∘ f₁ (A⇒B ⊗ A⇒B′) ∎
+ from∘f₂≈f₂ : from ≅N ∘ (f₂ (compose A⇒B B⇒C) +₁ f₂ (compose A⇒B′ B⇒C′)) ≈ f₂ (compose (A⇒B ⊗ A⇒B′) (B⇒C ⊗ B⇒C′))
+ from∘f₂≈f₂ = begin
from ≅N ∘ (f₂ (compose A⇒B B⇒C) +₁ f₂ (compose A⇒B′ B⇒C′)) ≈⟨ Equiv.refl ⟩
from ≅N ∘ ((i₂ P₁ ∘ f₂ B⇒C) +₁ (i₂ P₂ ∘ f₂ B⇒C′)) ≈⟨ refl⟩∘⟨ +₁∘+₁ ⟨
from ≅N ∘ (i₂ P₁ +₁ i₂ P₂) ∘ (f₂ B⇒C +₁ f₂ B⇒C′) ≈⟨ Equiv.refl ⟩
- from ≅N ∘ i₂ P₃′ ∘ f₂ (together B⇒C B⇒C′) ≈⟨ pullˡ (universal∘i₂≈h₂ P₃′) ⟩
- i₂ P₃ ∘ f₂ (together B⇒C B⇒C′) ∎
+ from ≅N ∘ i₂ P₃′ ∘ f₂ (B⇒C ⊗ B⇒C′) ≈⟨ pullˡ (universal∘i₂≈h₂ P₃′) ⟩
+ i₂ P₃ ∘ f₂ (B⇒C ⊗ B⇒C′) ∎
⊗-resp-≈
: {A A′ B B′ : Obj}
{f f′ : Cospan A B}
{g g′ : Cospan A′ B′}
- → Same f f′
- → Same g g′
- → Same (together f g) (together f′ g′)
+ → f Cospan.≈ f′
+ → g Cospan.≈ g′
+ → f ⊗ g Cospan.≈ f′ ⊗ g′
⊗-resp-≈ {_} {_} {_} {_} {f} {f′} {g} {g′} ≈f ≈g = record
{ ≅N = ≈f.≅N ⊗ᵢ ≈g.≅N
- ; from∘f₁≈f₁′ = from∘f₁≈f₁′
- ; from∘f₂≈f₂′ = from∘f₂≈f₂′
+ ; from∘f₁≈f₁ = from∘f₁≈f₁
+ ; from∘f₂≈f₂ = from∘f₂≈f₂
}
where
open 𝒞 using (-+-)
- module ≈f = Same ≈f
- module ≈g = Same ≈g
+ module ≈f = Cospan._≈_ ≈f
+ module ≈g = Cospan._≈_ ≈g
open HomReasoning
- open Cospan
+ open Cospan.Cospan
open 𝒞 using (+₁-cong₂; +₁∘+₁)
- from∘f₁≈f₁′ : (≈f.from +₁ ≈g.from) ∘ (f₁ f +₁ f₁ g) ≈ f₁ f′ +₁ f₁ g′
- from∘f₁≈f₁′ = begin 
+ from∘f₁≈f₁ : (≈f.from +₁ ≈g.from) ∘ (f₁ f +₁ f₁ g) ≈ f₁ f′ +₁ f₁ g′
+ from∘f₁≈f₁ = begin 
(≈f.from +₁ ≈g.from) ∘ (f₁ f +₁ f₁ g) ≈⟨ +₁∘+₁ ⟩
- (≈f.from ∘ f₁ f) +₁ (≈g.from ∘ f₁ g) ≈⟨ +₁-cong₂ (≈f.from∘f₁≈f₁′) (≈g.from∘f₁≈f₁′) ⟩
+ (≈f.from ∘ f₁ f) +₁ (≈g.from ∘ f₁ g) ≈⟨ +₁-cong₂ ≈f.from∘f₁≈f₁ ≈g.from∘f₁≈f₁ ⟩
f₁ f′ +₁ f₁ g′ ∎
- from∘f₂≈f₂′ : (≈f.from +₁ ≈g.from) ∘ (f₂ f +₁ f₂ g) ≈ f₂ f′ +₁ f₂ g′
- from∘f₂≈f₂′ = begin 
+ from∘f₂≈f₂ : (≈f.from +₁ ≈g.from) ∘ (f₂ f +₁ f₂ g) ≈ f₂ f′ +₁ f₂ g′
+ from∘f₂≈f₂ = begin 
(≈f.from +₁ ≈g.from) ∘ (f₂ f +₁ f₂ g) ≈⟨ +₁∘+₁ ⟩
- (≈f.from ∘ f₂ f) +₁ (≈g.from ∘ f₂ g) ≈⟨ +₁-cong₂ (≈f.from∘f₂≈f₂′) (≈g.from∘f₂≈f₂′) ⟩
+ (≈f.from ∘ f₂ f) +₁ (≈g.from ∘ f₂ g) ≈⟨ +₁-cong₂ ≈f.from∘f₂≈f₂ ≈g.from∘f₂≈f₂ ⟩
f₂ f′ +₁ f₂ g′ ∎
+private
+ ⊗′ : Bifunctor Cospans Cospans Cospans
+ ⊗′ = record
+ { F₀ = λ (A , A′) → A + A′
+ ; F₁ = λ (f , g) → f ⊗ g
+ ; identity = λ { {x , y} → id⊗id≈id {x} {y} }
+ ; homomorphism = λ { {_} {_} {_} {A⇒B , A⇒B′} {B⇒C , B⇒C′} → homomorphism A⇒B B⇒C A⇒B′ B⇒C′ }
+ ; F-resp-≈ = λ (≈f , ≈g) → ⊗-resp-≈ ≈f ≈g
+ }
+
⊗ : Bifunctor Cospans Cospans Cospans
-⊗ = record
- { F₀ = λ { (A , A′) → A + A′ }
- ; F₁ = λ { (f , g) → together f g }
- ; identity = λ { {x , y} → id⊗id≈id {x} {y} }
- ; homomorphism = λ { {_} {_} {_} {A⇒B , A⇒B′} {B⇒C , B⇒C′} → homomorphism A⇒B B⇒C A⇒B′ B⇒C′ }
- ; F-resp-≈ = λ { (≈f , ≈g) → ⊗-resp-≈ ≈f ≈g }
- }
+⊗ = ⊗′
+
+module ⊗ = Functor ⊗
diff --git a/Functor/Instance/Decorate.agda b/Functor/Instance/Decorate.agda
index e87f20c..fedddba 100644
--- a/Functor/Instance/Decorate.agda
+++ b/Functor/Instance/Decorate.agda
@@ -1,4 +1,5 @@
{-# OPTIONS --without-K --safe #-}
+{-# OPTIONS --hidden-argument-puns #-}
open import Categories.Category.Monoidal.Bundle using (MonoidalCategory; SymmetricMonoidalCategory)
open import Categories.Functor.Monoidal.Symmetric using (module Lax)
@@ -19,6 +20,7 @@ module Functor.Instance.Decorate
import Categories.Category.Monoidal.Reasoning as ⊗-Reasoning
import Categories.Diagram.Pushout as DiagramPushout
import Categories.Morphism.Reasoning as ⇒-Reasoning
+import Category.Diagram.Cospan 𝒞 as Cospan
open import Categories.Category using (Category; _[_,_]; _[_≈_]; _[_∘_])
open import Categories.Category.Cocartesian using (module CocartesianMonoidal)
@@ -27,10 +29,10 @@ open import Categories.Category.Monoidal.Utilities using (module Shorthands)
open import Categories.Functor.Core using (Functor)
open import Categories.Functor.Properties using ([_]-resp-≅)
open import Function.Base using () renaming (id to idf)
-open import Category.Instance.Cospans 𝒞 using (Cospan; Cospans; Same)
+open import Category.Instance.Cospans 𝒞 using (Cospans)
open import Category.Instance.DecoratedCospans 𝒞 F using (DecoratedCospans)
-open import Functor.Instance.Cospan.Stack using (⊗)
-open import Functor.Instance.DecoratedCospan.Stack using () renaming (⊗ to ⊗′)
+open import Functor.Instance.Cospan.Stack 𝒞 using (module ⊗)
+open import Functor.Instance.DecoratedCospan.Stack 𝒞 F using () renaming (module ⊗ to ⊗′)
module 𝒞 = FinitelyCocompleteCategory 𝒞
module 𝒟 = SymmetricMonoidalCategory 𝒟
@@ -40,7 +42,7 @@ module DecoratedCospans = Category DecoratedCospans
module mc𝒞 = CocartesianMonoidal 𝒞.U 𝒞.cocartesian
-- For every cospan there exists a free decorated cospan
--- i.e. the original cospan with the empty decoration
+-- i.e. the original cospan with the discrete decoration
private
variable
@@ -67,14 +69,14 @@ identity = record
open ⇒-Reasoning 𝒟.U
homomorphism : DecoratedCospans [ decorate (Cospans [ g ∘ f ]) ≈ DecoratedCospans [ decorate g ∘ decorate f ] ]
-homomorphism {B} {C} {g} {A} {f} = record
+homomorphism {g} {f} = record
{ cospans-≈ = Cospans.Equiv.refl
; same-deco = same-deco
}
where
- open Cospan f using (N; f₂)
- open Cospan g using () renaming (N to M; f₁ to g₁)
+ open Cospan.Cospan f using (N; f₂)
+ open Cospan.Cospan g using () renaming (N to M; f₁ to g₁)
open 𝒟 using (U; monoidal; _⊗₁_; unitorˡ-commute-from) renaming (module unitorˡ to λ-)
open 𝒞 using (¡; ⊥; ¡-unique; pushout) renaming ([_,_] to [_,_]′; _+₁_ to infixr 10 _+₁_ )
@@ -99,7 +101,7 @@ homomorphism {B} {C} {g} {A} {f} = record
F₁ ([ i₁ , i₂ ]′ 𝒞.∘ ¡ +₁ ¡ 𝒞.∘ λ⇐′) ∘ ε ∘ λ⇒ ∘ λ⇐ ≈⟨ refl⟩∘⟨ refl⟩∘⟨ refl⟩∘⟨ coherence-inv₃ monoidal ⟩
F₁ ([ i₁ , i₂ ]′ 𝒞.∘ ¡ +₁ ¡ 𝒞.∘ λ⇐′) ∘ ε ∘ λ⇒ ∘ ρ⇐ ≈⟨ refl⟩∘⟨ extendʳ unitorˡ-commute-from ⟨
F₁ ([ i₁ , i₂ ]′ 𝒞.∘ ¡ +₁ ¡ 𝒞.∘ λ⇐′) ∘ λ⇒ ∘ id ⊗₁ ε ∘ ρ⇐ ≈⟨ pushˡ F.homomorphism ⟩
- F₁ [ i₁ , i₂ ]′ ∘ F₁ (¡ +₁ ¡ 𝒞.∘ λ⇐′) ∘ λ⇒ ∘ id ⊗₁ ε ∘ ρ⇐ ≈⟨ push-center (sym F.homomorphism) ⟩
+ F₁ [ i₁ , i₂ ]′ ∘ F₁ (¡ +₁ ¡ 𝒞.∘ λ⇐′) ∘ λ⇒ ∘ id ⊗₁ ε ∘ ρ⇐ ≈⟨ push-center F.homomorphism ⟩
F₁ [ i₁ , i₂ ]′ ∘ F₁ (¡ +₁ ¡) ∘ F₁ λ⇐′ ∘ λ⇒ ∘ id ⊗₁ ε ∘ ρ⇐ ≈⟨ refl⟩∘⟨ refl⟩∘⟨ extendʳ (switch-fromtoˡ ([ F.F ]-resp-≅ unitorˡ) F.unitaryˡ) ⟨
F₁ [ i₁ , i₂ ]′ ∘ F₁ (¡ +₁ ¡) ∘ φ (⊥ , ⊥) ∘ ε ⊗₁ id ∘ id ⊗₁ ε ∘ ρ⇐ ≈⟨ refl⟩∘⟨ refl⟩∘⟨ refl⟩∘⟨ pullˡ (sym serialize₁₂) ⟩
F₁ [ i₁ , i₂ ]′ ∘ F₁ (¡ +₁ ¡) ∘ φ (⊥ , ⊥) ∘ ε ⊗₁ ε ∘ ρ⇐ ≈⟨ refl⟩∘⟨ extendʳ (φ-commute (¡ , ¡)) ⟨
@@ -126,19 +128,15 @@ Decorate = record
; F-resp-≈ = F-resp-≈
}
-module ⊗ = Functor (⊗ 𝒞)
-module ⊗′ = Functor (⊗′ 𝒞 F)
-open 𝒞 using (_+₁_)
-
Decorate-resp-⊗ : DecoratedCospans [ decorate (⊗.₁ (f , g)) ≈ ⊗′.₁ (decorate f , decorate g) ]
-Decorate-resp-⊗ {f = f} {g = g} = record
- { cospans-≈ = Cospans.Equiv.refl
+Decorate-resp-⊗ {f} {g} = record
+ { cospans-≈ = Cospan.≈-refl
; same-deco = same-deco
}
where
- open Cospan f using (N)
- open Cospan g using () renaming (N to M)
+ open Cospan.Cospan f using (N)
+ open Cospan.Cospan g using () renaming (N to M)
open 𝒟 using (U; monoidal; _⊗₁_; unitorˡ-commute-from) renaming (module unitorˡ to λ-)
open 𝒞 using (¡; ⊥; ¡-unique; pushout) renaming ([_,_] to [_,_]′; _+₁_ to infixr 10 _+₁_ )
@@ -165,4 +163,3 @@ Decorate-resp-⊗ {f = f} {g = g} = record
F₁ (¡ +₁ ¡) ∘ φ (⊥ , ⊥) ∘ ε ⊗₁ ε ∘ ρ⇐ ≈⟨ extendʳ (φ-commute (¡ , ¡)) ⟨
φ (N , M) ∘ F₁ ¡ ⊗₁ F₁ ¡ ∘ ε ⊗₁ ε ∘ ρ⇐ ≈⟨ refl⟩∘⟨ pullˡ (sym ⊗-distrib-over-∘) ⟩
φ (N , M) ∘ (F₁ ¡ ∘ ε) ⊗₁ (F₁ ¡ ∘ ε) ∘ ρ⇐ ∎
-
diff --git a/Functor/Instance/DecoratedCospan/Embed.agda b/Functor/Instance/DecoratedCospan/Embed.agda
index 4595a8f..77b16fa 100644
--- a/Functor/Instance/DecoratedCospan/Embed.agda
+++ b/Functor/Instance/DecoratedCospan/Embed.agda
@@ -19,6 +19,7 @@ import Categories.Category.Monoidal.Reasoning as ⊗-Reasoning
import Categories.Diagram.Pushout.Properties as PushoutProperties
import Categories.Morphism.Reasoning as ⇒-Reasoning
import Category.Diagram.Pushout as Pushout′
+import Category.Diagram.Cospan as Cospan
import Functor.Instance.Cospan.Embed 𝒞 as Embed
open import Categories.Category using (Category; _[_,_]; _[_≈_]; _[_∘_])
@@ -34,9 +35,9 @@ import Categories.Morphism as Morphism
open import Categories.Category.Cocartesian using (module CocartesianMonoidal)
open import Categories.Category.Monoidal.Utilities using (module Shorthands)
open import Categories.Functor using (Functor; _∘F_)
-open import Data.Product.Base using (_,_)
-open import Function.Base using () renaming (id to idf)
-open import Functor.Instance.DecoratedCospan.Stack using (⊗)
+open import Data.Product using (_,_)
+open import Function using () renaming (id to idf)
+open import Functor.Instance.DecoratedCospan.Stack 𝒞 F using (⊗)
module 𝒞 = FinitelyCocompleteCategory 𝒞
module 𝒟 = SymmetricMonoidalCategory 𝒟
@@ -62,7 +63,7 @@ R = Decorate ∘F Embed.R
B₁ : 𝒞.U [ A , C ] → 𝒞.U [ B , C ] → 𝒟.U [ 𝒟.unit , F.F₀ C ] → DecoratedCospans [ A , B ]
B₁ f g s = record
- { cospan = Embed.B₁ f g
+ { cospan = Cospan.cospan f g
; decoration = s
}
@@ -265,7 +266,6 @@ module _ where
where
module Decorate = Functor Decorate
- module ⊗ = Functor (⊗ 𝒞 F)
open 𝒞 using (_+₁_)
L-resp-⊗ : DecoratedCospans [ L.₁ (f +₁ g) ≈ ⊗.₁ (L.₁ f , L.₁ g) ]
diff --git a/Functor/Instance/DecoratedCospan/Stack.agda b/Functor/Instance/DecoratedCospan/Stack.agda
index 5c3c232..381ee06 100644
--- a/Functor/Instance/DecoratedCospan/Stack.agda
+++ b/Functor/Instance/DecoratedCospan/Stack.agda
@@ -19,6 +19,7 @@ import Categories.Diagram.Pushout as DiagramPushout
import Categories.Morphism as Morphism
import Categories.Morphism.Reasoning as ⇒-Reasoning
import Categories.Category.Monoidal.Reasoning as ⊗-Reasoning
+
import Functor.Instance.Cospan.Stack 𝒞 as Stack
open import Categories.Category using (Category; _[_,_]; _[_≈_]; _[_∘_])
@@ -26,13 +27,16 @@ open import Categories.Category.BinaryProducts using (BinaryProducts)
open import Categories.Category.Monoidal.Utilities using (module Shorthands)
open import Categories.Category.Monoidal.Properties using (coherence-inv₃)
open import Categories.Category.Monoidal.Braided.Properties using (braiding-coherence-inv)
+open import Categories.Functor using (Functor)
open import Categories.Functor.Bifunctor using (Bifunctor)
open import Categories.Functor.Properties using ([_]-resp-≅)
open import Categories.Category.Cocartesian using (module CocartesianMonoidal; module CocartesianSymmetricMonoidal)
open import Categories.Object.Initial using (Initial)
open import Categories.Object.Duality using (Coproduct⇒coProduct)
-open import Category.Instance.DecoratedCospans 𝒞 F using () renaming (DecoratedCospans to Cospans; Same to Same′)
-open import Category.Instance.Cospans 𝒞 using (Same; compose)
+open import Category.Instance.DecoratedCospans 𝒞 F using () renaming (DecoratedCospans to Cospans; _≈_ to _≈_′)
+
+import Category.Diagram.Cospan 𝒞 as Cospan
+
open import Cospan.Decorated 𝒞 F using (DecoratedCospan)
open import Data.Product.Base using (_,_)
@@ -52,10 +56,9 @@ private
variable
A A′ B B′ C C′ : Obj
-
together : Cospans [ A , B ] → Cospans [ A′ , B′ ] → Cospans [ A + A′ , B + B′ ]
together A⇒B A⇒B′ = record
- { cospan = Stack.together A⇒B.cospan A⇒B′.cospan
+ { cospan = A⇒B.cospan Cospan.⊗ A⇒B′.cospan
; decoration = ⊗-homo.η (A⇒B.N , A⇒B′.N) ∘ A⇒B.decoration ⊗₁ A⇒B′.decoration ∘ unitorʳ.to
}
where
@@ -108,9 +111,9 @@ homomorphism {A} {B} {C} {A′} {B′} {C′} f g f′ g′ = record
module _ where
open DecoratedCospan using (cospan)
- cospans-≈ : Same (Stack.together _ _) (compose (Stack.together _ _) (Stack.together _ _))
+ cospans-≈ : _ Cospan.⊗ _ Cospan.≈ Cospan.compose (_ Cospan.⊗ _) (_ Cospan.⊗ _)
cospans-≈ = Stack.homomorphism (f .cospan) (g .cospan) (f′ .cospan) (g′ .cospan)
- open Same cospans-≈ using () renaming (≅N to Q+Q′≅Q″) public
+ open Cospan._≈_ cospans-≈ using () renaming (≅N to Q+Q′≅Q″) public
module DecorationNames where
open DecoratedCospan f using (N) renaming (decoration to s) public
@@ -185,7 +188,7 @@ homomorphism {A} {B} {C} {A′} {B′} {C′} f g f′ g′ = record
≅∘[]+[]≈μ∘μ+μ = begin
≅ ∘ [ i₁ , i₂ ]′ +₁ [ i₁′ , i₂′ ]′ ≈⟨ refl⟩∘⟨ μ∘+ ⟩⊗⟨ μ∘+ ⟩
≅ ∘ (μ ∘ i₁ +₁ i₂) +₁ (μ ∘ i₁′ +₁ i₂′) ≈⟨ refl⟩∘⟨ introˡ +-η ⟩
- ≅ ∘ [ ι₁ , ι₂ ]′ ∘ (μ ∘ i₁ +₁ i₂) +₁ (μ ∘ i₁′ +₁ i₂′) ≈⟨ push-center (sym μ∘+) ⟩
+ ≅ ∘ [ ι₁ , ι₂ ]′ ∘ (μ ∘ i₁ +₁ i₂) +₁ (μ ∘ i₁′ +₁ i₂′) ≈⟨ push-center μ∘+ ⟩
≅ ∘ μ ∘ (ι₁ +₁ ι₂) ∘ (μ ∘ i₁ +₁ i₂) +₁ (μ ∘ i₁′ +₁ i₂′) ≈⟨ refl⟩∘⟨ refl⟩∘⟨ sym ⊗-distrib-over-∘ ⟩
≅ ∘ μ ∘ (ι₁ ∘ μ ∘ i₁ +₁ i₂) +₁ (ι₂ ∘ μ ∘ i₁′ +₁ i₂′) ≈⟨ refl⟩∘⟨ refl⟩∘⟨ (extendʳ μ-natural) ⟩⊗⟨ (extendʳ μ-natural) ⟩
≅ ∘ μ ∘ (μ ∘ ι₁ +₁ ι₁ ∘ i₁ +₁ i₂) +₁ (μ ∘ ι₂ +₁ ι₂ ∘ i₁′ +₁ i₂′) ≈⟨ refl⟩∘⟨ refl⟩∘⟨ (refl⟩∘⟨ sym ⊗-distrib-over-∘) ⟩⊗⟨ (refl⟩∘⟨ sym ⊗-distrib-over-∘) ⟩
@@ -221,7 +224,7 @@ homomorphism {A} {B} {C} {A′} {B′} {C′} f g f′ g′ = record
α⇐ ∘ w +₁ (x +₁ _ ∘ α⇒ ∘ _) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ extendʳ assoc-commute-from ⟩∘⟨refl ⟨
α⇐ ∘ w +₁ (α⇒ ∘ (x +₁ y) +₁ z ∘ +-swap +₁ id ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ (refl⟩∘⟨ pushˡ split₁ʳ) ⟩∘⟨refl ⟨
α⇐ ∘ w +₁ (α⇒ ∘ (x +₁ y ∘ +-swap) +₁ z ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ (refl⟩∘⟨ σ.⇒.sym-commute _ ⟩⊗⟨refl ⟩∘⟨refl) ⟩∘⟨refl ⟩
- α⇐ ∘ w +₁ (α⇒ ∘ (+-swap ∘ y +₁ x) +₁ z ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ push-center (sym split₁ˡ) ⟩∘⟨refl ⟩
+ α⇐ ∘ w +₁ (α⇒ ∘ (+-swap ∘ y +₁ x) +₁ z ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ push-center split₁ˡ ⟩∘⟨refl ⟩
α⇐ ∘ w +₁ (α⇒ ∘ +-swap +₁ id ∘ (y +₁ x) +₁ z ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ (refl⟩∘⟨ refl⟩∘⟨ assoc-commute-to) ⟩∘⟨refl ⟨
α⇐ ∘ w +₁ (α⇒ ∘ +-swap +₁ id ∘ α⇐ ∘ y +₁ (x +₁ z)) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ assoc²εβ ⟩∘⟨refl ⟩
α⇐ ∘ w +₁ ((α⇒ ∘ +-swap +₁ id ∘ α⇐) ∘ y +₁ (x +₁ z)) ∘ α⇒ ≈⟨ refl⟩∘⟨ pushˡ split₂ˡ ⟩
@@ -231,7 +234,7 @@ homomorphism {A} {B} {C} {A′} {B′} {C′} f g f′ g′ = record
μ∘μ+μ∘swap-inner : {X : Obj} → μ {X} ∘ μ +₁ μ ∘ swap-inner ≈ μ ∘ μ +₁ μ {X}
μ∘μ+μ∘swap-inner = begin
- μ ∘ μ +₁ μ ∘ α⇐ ∘ id +₁ (α⇒ ∘ +-swap +₁ id ∘ α⇐) ∘ α⇒ ≈⟨ push-center (sym serialize₁₂) ⟩
+ μ ∘ μ +₁ μ ∘ α⇐ ∘ id +₁ (α⇒ ∘ +-swap +₁ id ∘ α⇐) ∘ α⇒ ≈⟨ push-center serialize₁₂ ⟩
μ ∘ μ +₁ id ∘ id +₁ μ ∘ α⇐ ∘ id +₁ (α⇒ ∘ +-swap +₁ id ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩∘⟨ ⊗.identity ⟩⊗⟨refl ⟩∘⟨refl ⟨
μ ∘ μ +₁ id ∘ (id +₁ id) +₁ μ ∘ α⇐ ∘ id +₁ (α⇒ ∘ +-swap +₁ id ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩∘⟨ extendʳ assoc-commute-to ⟨
μ ∘ μ +₁ id ∘ α⇐ ∘ id +₁ (id +₁ μ) ∘ id +₁ (α⇒ ∘ +-swap +₁ id ∘ α⇐) ∘ α⇒ ≈⟨ pullˡ μ-assoc ⟩
@@ -243,7 +246,7 @@ homomorphism {A} {B} {C} {A′} {B′} {C′} f g f′ g′ = record
μ ∘ id +₁ (μ ∘ μ +₁ id ∘ +-swap +₁ id ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ pull-center (sym split₁ˡ) ⟩∘⟨refl ⟩
μ ∘ id +₁ (μ ∘ (μ ∘ +-swap) +₁ id ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ (refl⟩∘⟨ μ∘σ ⟩⊗⟨refl ⟩∘⟨refl) ⟩∘⟨refl ⟩
μ ∘ id +₁ (μ ∘ μ +₁ id ∘ α⇐) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩⊗⟨ (sym-assoc ○ flip-iso associator (μ-assoc ○ sym-assoc)) ⟩∘⟨refl ⟩
- μ ∘ id +₁ (μ ∘ id +₁ μ) ∘ α⇒ ≈⟨ push-center (sym split₂ʳ) ⟩
+ μ ∘ id +₁ (μ ∘ id +₁ μ) ∘ α⇒ ≈⟨ push-center split₂ʳ ⟩
μ ∘ id +₁ μ ∘ id +₁ (id +₁ μ) ∘ α⇒ ≈⟨ refl⟩∘⟨ refl⟩∘⟨ assoc-commute-from ⟨
μ ∘ id +₁ μ ∘ α⇒ ∘ (id +₁ id) +₁ μ ≈⟨ refl⟩∘⟨ refl⟩∘⟨ refl⟩∘⟨ ⊗.identity ⟩⊗⟨refl ⟩
μ ∘ id +₁ μ ∘ α⇒ ∘ id +₁ μ ≈⟨ refl⟩∘⟨ sym-assoc ⟩
@@ -370,13 +373,13 @@ homomorphism {A} {B} {C} {A′} {B′} {C′} f g f′ g′ = record
}
where
- open Same′ using (cospans-≈)
+ open _≈_′ using (cospans-≈)
module SameNames where
- open Same′ ≈f using () renaming (same-deco to ≅∘s≈t) public
- open Same′ ≈g using () renaming (same-deco to ≅∘s≈t′) public
- open Same (≈f .cospans-≈) using (module ≅N) public
- open Same (≈g .cospans-≈) using () renaming (module ≅N to ≅N′) public
+ open _≈_′ ≈f using () renaming (same-deco to ≅∘s≈t) public
+ open _≈_′ ≈g using () renaming (same-deco to ≅∘s≈t′) public
+ open Cospan._≈_ (≈f .cospans-≈) using (module ≅N) public
+ open Cospan._≈_ (≈g .cospans-≈) using () renaming (module ≅N to ≅N′) public
open SameNames
@@ -417,9 +420,11 @@ homomorphism {A} {B} {C} {A′} {B′} {C′} f g f′ g′ = record
⊗ : Bifunctor Cospans Cospans Cospans
⊗ = record
- { F₀ = λ { (A , A′) → A + A′ }
- ; F₁ = λ { (f , g) → together f g }
+ { F₀ = λ (A , A′) → A + A′
+ ; F₁ = λ (f , g) → together f g
; identity = λ { {x , y} → id⊗id≈id {x} {y} }
; homomorphism = λ { {_} {_} {_} {A⇒B , A⇒B′} {B⇒C , B⇒C′} → homomorphism A⇒B B⇒C A⇒B′ B⇒C′ }
- ; F-resp-≈ = λ { (≈f , ≈g) → ⊗-resp-≈ ≈f ≈g }
+ ; F-resp-≈ = λ (≈f , ≈g) → ⊗-resp-≈ ≈f ≈g
}
+
+module ⊗ = Functor ⊗
diff --git a/Functor/Instance/Endo/List.agda b/Functor/Instance/Endo/List.agda
new file mode 100644
index 0000000..67e3d0b
--- /dev/null
+++ b/Functor/Instance/Endo/List.agda
@@ -0,0 +1,15 @@
+{-# OPTIONS --without-K --safe #-}
+
+open import Level using (Level)
+
+module Functor.Instance.Endo.List {ℓ : Level} where
+
+import Functor.Instance.List {ℓ} {ℓ} as List
+
+open import Categories.Category.Instance.Setoids using (Setoids)
+open import Categories.Functor using (Endofunctor)
+
+-- List is only an endofunctor when the carrier sets and 
+-- equivalence relations live at the same level
+List : Endofunctor (Setoids ℓ ℓ)
+List = List.List
diff --git a/Functor/Instance/List.agda b/Functor/Instance/List.agda
new file mode 100644
index 0000000..a280218
--- /dev/null
+++ b/Functor/Instance/List.agda
@@ -0,0 +1,67 @@
+{-# OPTIONS --without-K --safe #-}
+
+open import Level using (Level; _⊔_)
+
+module Functor.Instance.List {c ℓ : Level} where
+
+import Data.List.Properties as ListProps
+import Data.List.Relation.Binary.Pointwise as PW
+
+open import Categories.Category.Instance.Setoids using (Setoids)
+open import Categories.Functor using (Functor)
+open import Data.Setoid using (∣_∣; _⇒ₛ_)
+open import Function.Base using (_∘_; id)
+open import Function.Bundles using (Func; _⟶ₛ_; _⟨$⟩_)
+open import Relation.Binary using (Setoid)
+
+open Functor
+open Setoid using (reflexive)
+open Func
+
+open import Data.Opaque.List as L hiding (List)
+
+private
+ variable
+ A B C : Setoid c ℓ
+
+open import Function.Construct.Identity using () renaming (function to Id)
+open import Function.Construct.Setoid using (_∙_)
+
+opaque
+
+ unfolding L.List
+
+ map-id
+ : (xs : ∣ Listₛ A ∣)
+ → (open Setoid (Listₛ A))
+ → mapₛ (Id _) ⟨$⟩ xs ≈ xs
+ map-id {A} = reflexive (Listₛ A) ∘ ListProps.map-id
+
+ List-homo
+ : (f : A ⟶ₛ B)
+ (g : B ⟶ₛ C)
+ → (xs : ∣ Listₛ A ∣)
+ → (open Setoid (Listₛ C))
+ → mapₛ (g ∙ f) ⟨$⟩ xs ≈ mapₛ g ⟨$⟩ (mapₛ f ⟨$⟩ xs)
+ List-homo {C = C} f g = reflexive (Listₛ C) ∘ ListProps.map-∘
+
+ List-resp-≈
+ : (f g : A ⟶ₛ B)
+ → (let open Setoid (A ⇒ₛ B) in f ≈ g)
+ → (let open Setoid (Listₛ A ⇒ₛ Listₛ B) in mapₛ f ≈ mapₛ g)
+ List-resp-≈ f g f≈g = PW.map⁺ (to f) (to g) (PW.refl f≈g)
+
+-- the List functor takes a carrier A to lists of A
+-- and the equivalence on A to pointwise equivalence on lists of A
+
+-- List on morphisms is the familiar map operation
+-- which applies the same function to every element of a list
+
+List : Functor (Setoids c ℓ) (Setoids c (c ⊔ ℓ))
+List .F₀ = Listₛ
+List .F₁ = mapₛ
+List .identity {_} {xs} = map-id xs
+List .homomorphism {f = f} {g} {xs} = List-homo f g xs
+List .F-resp-≈ {f = f} {g} f≈g = List-resp-≈ f g f≈g
+
+module List = Functor List
diff --git a/Functor/Instance/Monoidalize.agda b/Functor/Instance/Monoidalize.agda
new file mode 100644
index 0000000..6423109
--- /dev/null
+++ b/Functor/Instance/Monoidalize.agda
@@ -0,0 +1,43 @@
+{-# OPTIONS --without-K --safe #-}
+
+open import Level using (Level)
+open import Categories.Category using (Category)
+open import Categories.Category.Monoidal using (MonoidalCategory)
+open import Categories.Category.Cocartesian using (Cocartesian)
+
+module Functor.Instance.Monoidalize
+ {o o′ ℓ ℓ′ e e ′ : Level}
+ {C : Category o ℓ e}
+ (cocartesian : Cocartesian C)
+ (D : MonoidalCategory o ℓ e)
+ where
+
+open import Categories.Category.Cocartesian using (module CocartesianMonoidal)
+
+open import Categories.Functor using (Functor)
+open import Categories.Functor.Monoidal using (MonoidalFunctor)
+open import Categories.Category.Construction.Monoids using (Monoids)
+open import Categories.Category.Construction.Functors using (Functors)
+open import Categories.Category.Construction.MonoidalFunctors using (module Lax)
+open import Functor.Monoidal.Construction.MonoidValued cocartesian {D} using () renaming (F,⊗,ε to MonoidalFunctorOf)
+open import NaturalTransformation.Monoidal.Construction.MonoidValued cocartesian {D} using () renaming (β,⊗,ε to MonoidalNaturalTransformationOf)
+
+C-MC : MonoidalCategory o ℓ e
+C-MC = record { monoidal = +-monoidal }
+ where
+ open CocartesianMonoidal C cocartesian
+
+module C = MonoidalCategory C-MC
+module D = MonoidalCategory D
+
+open Lax using (MonoidalFunctors)
+open Functor
+
+Monoidalize : Functor (Functors C.U (Monoids D.monoidal)) (MonoidalFunctors C-MC D)
+Monoidalize .F₀ = MonoidalFunctorOf
+Monoidalize .F₁ α = MonoidalNaturalTransformationOf α
+Monoidalize .identity = D.Equiv.refl
+Monoidalize .homomorphism = D.Equiv.refl
+Monoidalize .F-resp-≈ x = x
+
+module Monoidalize = Functor Monoidalize
diff --git a/Functor/Instance/Multiset.agda b/Functor/Instance/Multiset.agda
new file mode 100644
index 0000000..b961c7b
--- /dev/null
+++ b/Functor/Instance/Multiset.agda
@@ -0,0 +1,72 @@
+{-# OPTIONS --without-K --safe #-}
+
+open import Level using (Level; _⊔_)
+
+module Functor.Instance.Multiset {c ℓ : Level} where
+
+import Data.Opaque.List as L
+import Data.List.Properties as ListProps
+import Data.List.Relation.Binary.Pointwise as PW
+
+open import Categories.Category.Instance.Setoids using (Setoids)
+open import Categories.Functor using (Functor)
+open import Data.List.Relation.Binary.Permutation.Setoid using (↭-setoid; ↭-reflexive-≋)
+open import Data.List.Relation.Binary.Permutation.Setoid.Properties using (map⁺)
+open import Data.Opaque.Multiset using (Multisetₛ; mapₛ)
+open import Data.Setoid using (∣_∣; _⇒ₛ_)
+open import Function.Base using (_∘_; id)
+open import Function.Bundles using (Func; _⟶ₛ_; _⟨$⟩_)
+open import Function.Construct.Identity using () renaming (function to Id)
+open import Function.Construct.Setoid using (_∙_)
+open import Relation.Binary using (Setoid)
+
+open Functor
+open Setoid using (reflexive)
+open Func
+
+private
+ variable
+ A B C : Setoid c ℓ
+
+-- the Multiset functor takes a carrier A to lists of A
+-- and the equivalence on A to permutation equivalence on lists of A
+
+-- Multiset on morphisms applies the same function to every element of a multiset
+
+opaque
+ unfolding mapₛ
+
+ map-id
+ : (xs : ∣ Multisetₛ A ∣)
+ → (open Setoid (Multisetₛ A))
+ → mapₛ (Id A) ⟨$⟩ xs ≈ xs
+ map-id {A} = reflexive (Multisetₛ A) ∘ ListProps.map-id
+
+opaque
+ unfolding mapₛ
+
+ Multiset-homo
+ : (f : A ⟶ₛ B)
+ (g : B ⟶ₛ C)
+ → (xs : ∣ Multisetₛ A ∣)
+ → (open Setoid (Multisetₛ C))
+ → mapₛ (g ∙ f) ⟨$⟩ xs ≈ mapₛ g ⟨$⟩ (mapₛ f ⟨$⟩ xs)
+ Multiset-homo {C = C} f g = reflexive (Multisetₛ C) ∘ ListProps.map-∘
+
+opaque
+ unfolding mapₛ
+
+ Multiset-resp-≈
+ : (f g : A ⟶ₛ B)
+ → (let open Setoid (A ⇒ₛ B) in f ≈ g)
+ → (let open Setoid (Multisetₛ A ⇒ₛ Multisetₛ B) in mapₛ f ≈ mapₛ g)
+ Multiset-resp-≈ {A} {B} f g f≈g = ↭-reflexive-≋ B (PW.map⁺ (to f) (to g) (PW.refl f≈g))
+
+Multiset : Functor (Setoids c ℓ) (Setoids c (c ⊔ ℓ))
+Multiset .F₀ = Multisetₛ
+Multiset .F₁ = mapₛ
+Multiset .identity {A} {xs} = map-id {A} xs
+Multiset .homomorphism {f = f} {g} {xs} = Multiset-homo f g xs
+Multiset .F-resp-≈ {A} {B} {f} {g} f≈g = Multiset-resp-≈ f g f≈g
+
+module Multiset = Functor Multiset
diff --git a/Functor/Instance/Nat/Circ.agda b/Functor/Instance/Nat/Circ.agda
new file mode 100644
index 0000000..88a6ec6
--- /dev/null
+++ b/Functor/Instance/Nat/Circ.agda
@@ -0,0 +1,56 @@
+{-# OPTIONS --without-K --safe #-}
+
+open import Level using (Level)
+
+module Functor.Instance.Nat.Circ {ℓ : Level} where
+
+import Data.List.Relation.Binary.Permutation.Setoid as ↭
+
+open import Categories.Category.Instance.Nat using (Nat)
+open import Categories.Functor using (Functor; _∘F_)
+open import Categories.Morphism.Notation using (_[_≅_])
+open import Category.Instance.Setoids.SymmetricMonoidal {ℓ} {ℓ} using (Setoids-×)
+open import Data.Circuit using (mk≈)
+open import Data.Circuit {ℓ} using (Circuitₛ; mkCircuitₛ; edgesₛ)
+open import Data.Circuit.Gate using (Gates)
+open import Data.Nat using (ℕ)
+open import Data.Opaque.Multiset using (Multisetₛ)
+open import Data.Product using (proj₁; proj₂; Σ-syntax)
+open import Functor.Free.Instance.CMonoid using (Free)
+open import Functor.Instance.Nat.Edge {ℓ} Gates using (Edge)
+open import Functor.Properties using (define-by-pw-iso)
+
+open import Category.Construction.CMonoids Setoids-×.symmetric using (CMonoids)
+open import Category.Construction.CMonoids.Properties Setoids-×.symmetric using (transport-by-iso)
+open import Object.Monoid.Commutative Setoids-×.symmetric using (CommutativeMonoid)
+
+Edges : Functor Nat CMonoids
+Edges = Free ∘F Edge
+
+module Edges = Functor Edges
+module Edge = Functor Edge
+
+opaque
+ unfolding Multisetₛ
+ Edges≅Circₛ : (n : ℕ) → Setoids-×.U [ Multisetₛ (Edge.₀ n) ≅ Circuitₛ n ]
+ Edges≅Circₛ n = record
+ { from = mkCircuitₛ
+ ; to = edgesₛ
+ ; iso = record
+   { isoˡ = ↭.↭-refl (Edge.₀ n)
+ ; isoʳ = mk≈ (↭.↭-refl (Edge.₀ n))
+ }
+ }
+
+private
+ Edges≅ : (n : ℕ) → Σ[ M ∈ CommutativeMonoid ] CMonoids [ Edges.₀ n ≅ M ]
+ Edges≅ n = transport-by-iso (Edges.₀ n) (Edges≅Circₛ n)
+
+Circuitₘ : ℕ → CommutativeMonoid
+Circuitₘ n = proj₁ (Edges≅ n)
+
+Edges≅Circₘ : (n : ℕ) → CMonoids [ Edges.₀ n ≅ Circuitₘ n ]
+Edges≅Circₘ n = proj₂ (Edges≅ n)
+
+Circ : Functor Nat CMonoids
+Circ = proj₁ (define-by-pw-iso Edges Circuitₘ Edges≅Circₘ)
diff --git a/Functor/Instance/Nat/Edge.agda b/Functor/Instance/Nat/Edge.agda
new file mode 100644
index 0000000..c69a1db
--- /dev/null
+++ b/Functor/Instance/Nat/Edge.agda
@@ -0,0 +1,60 @@
+{-# OPTIONS --without-K --safe #-}
+
+open import Data.Hypergraph.Label using (HypergraphLabel)
+open import Level using (Level; 0ℓ)
+
+module Functor.Instance.Nat.Edge {ℓ : Level} (HL : HypergraphLabel) where
+
+import Data.Vec as Vec
+import Data.Vec.Properties as VecProps
+
+open import Categories.Category.Instance.Nat using (Nat)
+open import Categories.Category.Instance.Setoids using (Setoids)
+open import Categories.Functor using (Functor)
+open import Data.Fin using (Fin)
+open import Data.Fin.Properties using (cast-is-id)
+open import Data.Hypergraph.Edge {ℓ} HL as Edge using (Edgeₛ; map; mapₛ; _≈_)
+open import Data.Nat using (ℕ)
+open import Data.Vec.Relation.Binary.Equality.Cast using (≈-reflexive)
+open import Function using (id; _∘_; Func; _⟶ₛ_)
+open import Relation.Binary using (Setoid)
+open import Relation.Binary.PropositionalEquality as ≡ using (_≡_; _≗_)
+
+module HL = HypergraphLabel HL
+
+open Edge.Edge
+open Edge._≈_
+open Func
+open Functor
+
+map-id : {v : ℕ} {e : Edge.Edge v} → map id e ≈ e
+map-id .≡arity = ≡.refl
+map-id .≡label = HL.≈-reflexive ≡.refl
+map-id {_} {e} .≡ports = ≡.cong (ports e) ∘ ≡.sym ∘ cast-is-id ≡.refl
+
+map-∘
+ : {n m o : ℕ}
+ (f : Fin n → Fin m)
+ (g : Fin m → Fin o)
+ {e : Edge.Edge n}
+ → map (g ∘ f) e ≈ map g (map f e)
+map-∘ f g .≡arity = ≡.refl
+map-∘ f g .≡label = HL.≈-reflexive ≡.refl
+map-∘ f g {e} .≡ports = ≡.cong (g ∘ f ∘ ports e) ∘ ≡.sym ∘ cast-is-id ≡.refl
+
+map-resp-≗
+ : {n m : ℕ}
+ {f g : Fin n → Fin m}
+ → f ≗ g
+ → {e : Edge.Edge n}
+ → map f e ≈ map g e
+map-resp-≗ f≗g .≡arity = ≡.refl
+map-resp-≗ f≗g .≡label = HL.≈-reflexive ≡.refl
+map-resp-≗ {g = g} f≗g {e} .≡ports i = ≡.trans (f≗g (ports e i)) (≡.cong (g ∘ ports e) (≡.sym (cast-is-id ≡.refl i)))
+
+Edge : Functor Nat (Setoids ℓ ℓ)
+Edge .F₀ = Edgeₛ
+Edge .F₁ = mapₛ
+Edge .identity = map-id
+Edge .homomorphism {f = f} {g} = map-∘ f g
+Edge .F-resp-≈ = map-resp-≗
diff --git a/Functor/Instance/Nat/Preimage.agda b/Functor/Instance/Nat/Preimage.agda
new file mode 100644
index 0000000..7da00f4
--- /dev/null
+++ b/Functor/Instance/Nat/Preimage.agda
@@ -0,0 +1,65 @@
+{-# OPTIONS --without-K --safe #-}
+
+module Functor.Instance.Nat.Preimage where
+
+open import Categories.Category.Instance.Nat using (Natop)
+open import Categories.Category.Instance.Setoids using (Setoids)
+open import Categories.Functor using (Functor)
+open import Data.Fin.Base using (Fin)
+open import Data.Bool.Base using (Bool)
+open import Data.Nat.Base using (ℕ)
+open import Data.Subset.Functional using (Subset)
+open import Data.Vec.Functional.Relation.Binary.Equality.Setoid using (≋-setoid)
+open import Function.Base using (id; _∘_)
+open import Function.Bundles using (Func; _⟶ₛ_)
+open import Function.Construct.Identity using () renaming (function to Id)
+open import Function.Construct.Setoid using (setoid; _∙_)
+open import Level using (0ℓ)
+open import Relation.Binary using (Rel; Setoid)
+open import Relation.Binary.PropositionalEquality as ≡ using (_≗_)
+
+open Functor
+open Func
+
+_≈_ : {X Y : Setoid 0ℓ 0ℓ} → Rel (X ⟶ₛ Y) 0ℓ
+_≈_ {X} {Y} = Setoid._≈_ (setoid X Y)
+infixr 4 _≈_
+
+private
+ variable A B C : ℕ
+
+-- action on objects (Subset n)
+Subsetₛ : ℕ → Setoid 0ℓ 0ℓ
+Subsetₛ = ≋-setoid (≡.setoid Bool)
+
+-- action of Preimage on morphisms (contravariant)
+Preimage₁ : (Fin A → Fin B) → Subsetₛ B ⟶ₛ Subsetₛ A
+to (Preimage₁ f) i = i ∘ f
+cong (Preimage₁ f) x≗y = x≗y ∘ f
+
+-- Preimage respects identity
+Preimage-identity : Preimage₁ id ≈ Id (Subsetₛ A)
+Preimage-identity {A} = Setoid.refl (Subsetₛ A)
+
+-- Preimage flips composition
+Preimage-homomorphism
+ : {A B C : ℕ}
+ (f : Fin A → Fin B)
+ (g : Fin B → Fin C)
+ → Preimage₁ (g ∘ f) ≈ Preimage₁ f ∙ Preimage₁ g
+Preimage-homomorphism {A} _ _ = Setoid.refl (Subsetₛ A)
+
+-- Preimage respects equality
+Preimage-resp-≈
+ : {f g : Fin A → Fin B}
+ → f ≗ g
+ → Preimage₁ f ≈ Preimage₁ g
+Preimage-resp-≈ f≗g {v} = ≡.cong v ∘ f≗g
+
+-- the Preimage functor
+Preimage : Functor Natop (Setoids 0ℓ 0ℓ)
+F₀ Preimage = Subsetₛ
+F₁ Preimage = Preimage₁
+identity Preimage = Preimage-identity
+homomorphism Preimage {f = f} {g} {v} = Preimage-homomorphism g f {v}
+F-resp-≈ Preimage = Preimage-resp-≈
diff --git a/Functor/Instance/Nat/Pull.agda b/Functor/Instance/Nat/Pull.agda
new file mode 100644
index 0000000..b1764d9
--- /dev/null
+++ b/Functor/Instance/Nat/Pull.agda
@@ -0,0 +1,81 @@
+{-# OPTIONS --without-K --safe #-}
+
+module Functor.Instance.Nat.Pull where
+
+open import Categories.Category.Instance.Nat using (Natop)
+open import Categories.Category.Instance.Setoids using (Setoids)
+open import Categories.Functor using (Functor)
+open import Data.Fin.Base using (Fin)
+open import Data.Nat.Base using (ℕ)
+open import Function.Base using (id; _∘_)
+open import Function.Bundles using (Func; _⟶ₛ_)
+open import Function.Construct.Identity using () renaming (function to Id)
+open import Function.Construct.Setoid using (setoid; _∙_)
+open import Level using (0ℓ)
+open import Relation.Binary using (Rel; Setoid)
+open import Relation.Binary.PropositionalEquality as ≡ using (_≗_)
+open import Data.Circuit.Value using (Monoid)
+open import Data.System.Values Monoid using (Values)
+open import Data.Unit using (⊤; tt)
+
+open Functor
+open Func
+
+-- Pull takes a natural number n to the setoid Values n
+
+private
+
+ variable A B C : ℕ
+
+ _≈_ : {X Y : Setoid 0ℓ 0ℓ} → Rel (X ⟶ₛ Y) 0ℓ
+ _≈_ {X} {Y} = Setoid._≈_ (setoid X Y)
+
+ infixr 4 _≈_
+
+ opaque
+
+ unfolding Values
+
+ -- action of Pull on morphisms (contravariant)
+ Pull₁ : (Fin A → Fin B) → Values B ⟶ₛ Values A
+ to (Pull₁ f) i = i ∘ f
+ cong (Pull₁ f) x≗y = x≗y ∘ f
+
+ -- Pull respects identity
+ Pull-identity : Pull₁ id ≈ Id (Values A)
+ Pull-identity {A} = Setoid.refl (Values A)
+
+ opaque
+
+ unfolding Pull₁
+
+ -- Pull flips composition
+ Pull-homomorphism
+ : (f : Fin A → Fin B)
+ (g : Fin B → Fin C)
+ → Pull₁ (g ∘ f) ≈ Pull₁ f ∙ Pull₁ g
+ Pull-homomorphism {A} _ _ = Setoid.refl (Values A)
+
+ -- Pull respects equality
+ Pull-resp-≈
+ : {f g : Fin A → Fin B}
+ → f ≗ g
+ → Pull₁ f ≈ Pull₁ g
+ Pull-resp-≈ f≗g {v} = ≡.cong v ∘ f≗g
+
+opaque
+
+ unfolding Pull₁
+
+ Pull-defs : ⊤
+ Pull-defs = tt
+
+-- the Pull functor
+Pull : Functor Natop (Setoids 0ℓ 0ℓ)
+F₀ Pull = Values
+F₁ Pull = Pull₁
+identity Pull = Pull-identity
+homomorphism Pull {f = f} {g} = Pull-homomorphism g f
+F-resp-≈ Pull = Pull-resp-≈
+
+module Pull = Functor Pull
diff --git a/Functor/Instance/Nat/Push.agda b/Functor/Instance/Nat/Push.agda
new file mode 100644
index 0000000..8126006
--- /dev/null
+++ b/Functor/Instance/Nat/Push.agda
@@ -0,0 +1,79 @@
+{-# OPTIONS --without-K --safe #-}
+
+module Functor.Instance.Nat.Push where
+
+open import Categories.Functor using (Functor)
+open import Categories.Category.Instance.Nat using (Nat)
+open import Categories.Category.Instance.Setoids using (Setoids)
+open import Data.Circuit.Merge using (merge; merge-cong₁; merge-cong₂; merge-⁅⁆; merge-preimage)
+open import Data.Fin.Base using (Fin)
+open import Data.Fin.Preimage using (preimage; preimage-cong₁)
+open import Data.Nat.Base using (ℕ)
+open import Data.Subset.Functional using (⁅_⁆)
+open import Function.Base using (id; _∘_)
+open import Function.Bundles using (Func; _⟶ₛ_)
+open import Function.Construct.Identity using () renaming (function to Id)
+open import Function.Construct.Setoid using (setoid; _∙_)
+open import Level using (0ℓ)
+open import Relation.Binary using (Rel; Setoid)
+open import Relation.Binary.PropositionalEquality as ≡ using (_≗_)
+open import Data.Circuit.Value using (Monoid)
+open import Data.System.Values Monoid using (Values)
+open import Data.Unit using (⊤; tt)
+
+open Func
+open Functor
+
+-- Push sends a natural number n to Values n
+
+private
+
+ variable A B C : ℕ
+
+ _≈_ : {X Y : Setoid 0ℓ 0ℓ} → Rel (X ⟶ₛ Y) 0ℓ
+ _≈_ {X} {Y} = Setoid._≈_ (setoid X Y)
+ infixr 4 _≈_
+
+ opaque
+
+ unfolding Values
+
+ -- action of Push on morphisms (covariant)
+ Push₁ : (Fin A → Fin B) → Values A ⟶ₛ Values B
+ to (Push₁ f) v = merge v ∘ preimage f ∘ ⁅_⁆
+ cong (Push₁ f) x≗y = merge-cong₁ x≗y ∘ preimage f ∘ ⁅_⁆
+
+ -- Push respects identity
+ Push-identity : Push₁ id ≈ Id (Values A)
+ Push-identity {_} {v} = merge-⁅⁆ v
+
+ -- Push respects composition
+ Push-homomorphism
+ : {f : Fin A → Fin B}
+ {g : Fin B → Fin C}
+ → Push₁ (g ∘ f) ≈ Push₁ g ∙ Push₁ f
+ Push-homomorphism {f = f} {g} {v} = merge-preimage f v ∘ preimage g ∘ ⁅_⁆
+
+ -- Push respects equality
+ Push-resp-≈
+ : {f g : Fin A → Fin B}
+ → f ≗ g
+ → Push₁ f ≈ Push₁ g
+ Push-resp-≈ f≗g {v} = merge-cong₂ v ∘ preimage-cong₁ f≗g ∘ ⁅_⁆
+
+opaque
+
+ unfolding Push₁
+
+ Push-defs : ⊤
+ Push-defs = tt
+
+-- the Push functor
+Push : Functor Nat (Setoids 0ℓ 0ℓ)
+F₀ Push = Values
+F₁ Push = Push₁
+identity Push = Push-identity
+homomorphism Push = Push-homomorphism
+F-resp-≈ Push = Push-resp-≈
+
+module Push = Functor Push
diff --git a/Functor/Instance/Nat/System.agda b/Functor/Instance/Nat/System.agda
new file mode 100644
index 0000000..05e1e7b
--- /dev/null
+++ b/Functor/Instance/Nat/System.agda
@@ -0,0 +1,110 @@
+{-# OPTIONS --without-K --safe #-}
+
+module Functor.Instance.Nat.System where
+
+
+open import Level using (suc; 0ℓ)
+
+open import Categories.Category.Instance.Nat using (Nat)
+open import Categories.Category.Instance.Setoids using (Setoids)
+open import Categories.Functor.Core using (Functor)
+open import Data.Circuit.Value using (Monoid)
+open import Data.Fin.Base using (Fin)
+open import Data.Nat.Base using (ℕ)
+open import Data.Product.Base using (_,_; _×_)
+open import Data.System {suc 0ℓ} using (System; _≤_; Systemₛ)
+open import Data.System.Values Monoid using (module ≋)
+open import Data.Unit using (⊤; tt)
+open import Function.Base using (id; _∘_)
+open import Function.Bundles using (Func; _⟶ₛ_; _⟨$⟩_)
+open import Function.Construct.Identity using () renaming (function to Id)
+open import Function.Construct.Setoid using (_∙_)
+open import Functor.Instance.Nat.Pull using (Pull)
+open import Functor.Instance.Nat.Push using (Push)
+open import Relation.Binary.PropositionalEquality as ≡ using (_≗_)
+
+open Func
+open Functor
+open _≤_
+
+private
+
+ variable A B C : ℕ
+
+ opaque
+
+ map : (Fin A → Fin B) → System A → System B
+ map f X = let open System X in record
+ { S = S
+ ; fₛ = fₛ ∙ Pull.₁ f
+ ; fₒ = Push.₁ f ∙ fₒ
+ }
+
+ ≤-cong : (f : Fin A → Fin B) {X Y : System A} → Y ≤ X → map f Y ≤ map f X
+ ⇒S (≤-cong f x≤y) = ⇒S x≤y
+ ≗-fₛ (≤-cong f x≤y) = ≗-fₛ x≤y ∘ to (Pull.₁ f)
+ ≗-fₒ (≤-cong f x≤y) = cong (Push.₁ f) ∘ ≗-fₒ x≤y
+
+ System₁ : (Fin A → Fin B) → Systemₛ A ⟶ₛ Systemₛ B
+ to (System₁ f) = map f
+ cong (System₁ f) (x≤y , y≤x) = ≤-cong f x≤y , ≤-cong f y≤x
+
+ opaque
+
+ unfolding System₁
+
+ id-x≤x : {X : System A} → System₁ id ⟨$⟩ X ≤ X
+ ⇒S (id-x≤x) = Id _
+ ≗-fₛ (id-x≤x {_} {x}) i s = cong (System.fₛ x) Pull.identity
+ ≗-fₒ (id-x≤x {A} {x}) s = Push.identity
+
+ x≤id-x : {x : System A} → x ≤ System₁ id ⟨$⟩ x
+ ⇒S x≤id-x = Id _
+ ≗-fₛ (x≤id-x {A} {x}) i s = cong (System.fₛ x) (≋.sym Pull.identity)
+ ≗-fₒ (x≤id-x {A} {x}) s = ≋.sym Push.identity
+
+ System-homomorphism
+ : {f : Fin A → Fin B}
+ {g : Fin B → Fin C} 
+ {X : System A}
+ → System₁ (g ∘ f) ⟨$⟩ X ≤ System₁ g ⟨$⟩ (System₁ f ⟨$⟩ X)
+ × System₁ g ⟨$⟩ (System₁ f ⟨$⟩ X) ≤ System₁ (g ∘ f) ⟨$⟩ X
+ System-homomorphism {f = f} {g} {X} = left , right
+ where
+ open System X
+ left : map (g ∘ f) X ≤ map g (map f X)
+ left .⇒S = Id S
+ left .≗-fₛ i s = cong fₛ Pull.homomorphism
+ left .≗-fₒ s = Push.homomorphism
+ right : map g (map f X) ≤ map (g ∘ f) X
+ right .⇒S = Id S
+ right .≗-fₛ i s = cong fₛ (≋.sym Pull.homomorphism)
+ right .≗-fₒ s = ≋.sym Push.homomorphism
+
+ System-resp-≈
+ : {f g : Fin A → Fin B}
+ → f ≗ g
+ → {X : System A}
+ → System₁ f ⟨$⟩ X ≤ System₁ g ⟨$⟩ X
+ × System₁ g ⟨$⟩ X ≤ System₁ f ⟨$⟩ X
+ System-resp-≈ {A} {B} {f = f} {g} f≗g {X} = both f≗g , both (≡.sym ∘ f≗g)
+ where
+ open System X
+ both : {f g : Fin A → Fin B} → f ≗ g → map f X ≤ map g X
+ both f≗g .⇒S = Id S
+ both f≗g .≗-fₛ i s = cong fₛ (Pull.F-resp-≈ f≗g {i})
+ both {f} {g} f≗g .≗-fₒ s = Push.F-resp-≈ f≗g
+
+opaque
+ unfolding System₁
+ Sys-defs : ⊤
+ Sys-defs = tt
+
+Sys : Functor Nat (Setoids (suc 0ℓ) (suc 0ℓ))
+Sys .F₀ = Systemₛ
+Sys .F₁ = System₁
+Sys .identity = id-x≤x , x≤id-x
+Sys .homomorphism {x = X} = System-homomorphism {X = X}
+Sys .F-resp-≈ = System-resp-≈
+
+module Sys = Functor Sys