Mercurial > hg > Members > kono > Proof > category
annotate HomReasoning.agda @ 299:8c72f5284bc8
remove module parameter from yoneda functor
| author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Sun, 29 Sep 2013 13:36:42 +0900 |
| parents | 24e83b8b81be |
| children | 3e44951b9bdb |
| rev | line source |
|---|---|
| 56 | 1 module HomReasoning where |
| 31 | 2 |
| 3 -- Shinji KONO <kono@ie.u-ryukyu.ac.jp> | |
| 4 | |
| 5 open import Category -- https://github.com/konn/category-agda | |
| 6 open import Level | |
| 7 open Functor | |
| 8 | |
| 9 | |
| 10 -- F(f) | |
| 11 -- F(a) ---→ F(b) | |
| 12 -- | | | |
| 13 -- |t(a) |t(b) G(f)t(a) = t(b)F(f) | |
| 14 -- | | | |
| 15 -- v v | |
| 16 -- G(a) ---→ G(b) | |
| 17 -- G(f) | |
| 18 | |
| 19 record IsNTrans {c₁ c₂ ℓ c₁′ c₂′ ℓ′ : Level} (D : Category c₁ c₂ ℓ) (C : Category c₁′ c₂′ ℓ′) | |
| 20 ( F G : Functor D C ) | |
| 21 (TMap : (A : Obj D) → Hom C (FObj F A) (FObj G A)) | |
| 22 : Set (suc (c₁ ⊔ c₂ ⊔ ℓ ⊔ c₁′ ⊔ c₂′ ⊔ ℓ′)) where | |
| 23 field | |
| 130 | 24 commute : {a b : Obj D} {f : Hom D a b} |
| 31 | 25 → C [ C [ ( FMap G f ) o ( TMap a ) ] ≈ C [ (TMap b ) o (FMap F f) ] ] |
| 26 | |
| 130 | 27 record NTrans {c₁ c₂ ℓ c₁′ c₂′ ℓ′ : Level} (domain : Category c₁ c₂ ℓ) (codomain : Category c₁′ c₂′ ℓ′) |
| 28 (F G : Functor domain codomain ) | |
| 31 | 29 : Set (suc (c₁ ⊔ c₂ ⊔ ℓ ⊔ c₁′ ⊔ c₂′ ⊔ ℓ′)) where |
| 30 field | |
| 31 TMap : (A : Obj domain) → Hom codomain (FObj F A) (FObj G A) | |
| 32 isNTrans : IsNTrans domain codomain F G TMap | |
| 33 | |
| 34 | |
| 35 module ≈-Reasoning {c₁ c₂ ℓ : Level} (A : Category c₁ c₂ ℓ) where | |
| 36 open import Relation.Binary.Core | |
| 37 | |
| 38 _o_ : {a b c : Obj A } ( x : Hom A a b ) ( y : Hom A c a ) → Hom A c b | |
| 39 x o y = A [ x o y ] | |
| 40 | |
| 41 _≈_ : {a b : Obj A } → Rel (Hom A a b) ℓ | |
| 42 x ≈ y = A [ x ≈ y ] | |
| 43 | |
| 44 infixr 9 _o_ | |
| 45 infix 4 _≈_ | |
| 46 | |
| 47 refl-hom : {a b : Obj A } { x : Hom A a b } → x ≈ x | |
| 48 refl-hom = IsEquivalence.refl (IsCategory.isEquivalence ( Category.isCategory A )) | |
| 49 | |
| 50 trans-hom : {a b : Obj A } { x y z : Hom A a b } → | |
| 51 x ≈ y → y ≈ z → x ≈ z | |
| 52 trans-hom b c = ( IsEquivalence.trans (IsCategory.isEquivalence ( Category.isCategory A ))) b c | |
| 53 | |
| 54 -- some short cuts | |
| 55 | |
| 56 car : {a b c : Obj A } {x y : Hom A a b } { f : Hom A c a } → | |
| 57 x ≈ y → ( x o f ) ≈ ( y o f ) | |
| 58 car {f} eq = ( IsCategory.o-resp-≈ ( Category.isCategory A )) ( refl-hom ) eq | |
| 59 | |
| 60 cdr : {a b c : Obj A } {x y : Hom A a b } { f : Hom A b c } → | |
| 61 x ≈ y → f o x ≈ f o y | |
| 62 cdr {f} eq = ( IsCategory.o-resp-≈ ( Category.isCategory A )) eq (refl-hom ) | |
| 63 | |
| 64 id : (a : Obj A ) → Hom A a a | |
| 65 id a = (Id {_} {_} {_} {A} a) | |
| 66 | |
| 67 idL : {a b : Obj A } { f : Hom A b a } → id a o f ≈ f | |
| 68 idL = IsCategory.identityL (Category.isCategory A) | |
| 69 | |
| 70 idR : {a b : Obj A } { f : Hom A a b } → f o id a ≈ f | |
| 71 idR = IsCategory.identityR (Category.isCategory A) | |
| 72 | |
| 73 sym : {a b : Obj A } { f g : Hom A a b } → f ≈ g → g ≈ f | |
| 74 sym = IsEquivalence.sym (IsCategory.isEquivalence (Category.isCategory A)) | |
| 75 | |
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76 -- working on another cateogry |
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77 idL1 : { c₁ c₂ ℓ : Level} (A : Category c₁ c₂ ℓ) {a b : Obj A } { f : Hom A b a } → A [ A [ Id {_} {_} {_} {A} a o f ] ≈ f ] |
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78 idL1 A = IsCategory.identityL (Category.isCategory A) |
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79 |
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80 idR1 : { c₁ c₂ ℓ : Level} (A : Category c₁ c₂ ℓ) {a b : Obj A } { f : Hom A a b } → A [ A [ f o Id {_} {_} {_} {A} a ] ≈ f ] |
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81 idR1 A = IsCategory.identityR (Category.isCategory A) |
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82 |
| 67 | 83 -- How to prove this? |
| 75 | 84 ≡-≈ : {a b : Obj A } { x y : Hom A a b } → (x≈y : x ≡ y ) → x ≈ y |
| 85 ≡-≈ refl = refl-hom | |
| 86 | |
| 87 -- ≈-≡ : {a b : Obj A } { x y : Hom A a b } → (x≈y : x ≈ y ) → x ≡ y | |
| 88 -- ≈-≡ x≈y = irr x≈y | |
| 89 ≡-cong : { c₁′ c₂′ ℓ′ : Level} {B : Category c₁′ c₂′ ℓ′} {x y : Obj B } { a b : Hom B x y } {x' y' : Obj A } → | |
| 152 | 90 a ≡ b → (f : Hom B x y → Hom A x' y' ) → f a ≈ f b |
| 91 ≡-cong refl f = ≡-≈ refl | |
| 75 | 92 |
| 67 | 93 -- cong-≈ : { c₁′ c₂′ ℓ′ : Level} {B : Category c₁′ c₂′ ℓ′} {x y : Obj B } { a b : Hom B x y } {x' y' : Obj A } → |
| 94 -- B [ a ≈ b ] → (f : Hom B x y → Hom A x' y' ) → f a ≈ f b | |
| 75 | 95 -- cong-≈ eq f = {!!} |
| 67 | 96 |
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97 assoc : {a b c d : Obj A } {f : Hom A c d} {g : Hom A b c} {h : Hom A a b} |
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98 → f o ( g o h ) ≈ ( f o g ) o h |
| 31 | 99 assoc = IsCategory.associative (Category.isCategory A) |
| 100 | |
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101 -- working on another cateogry |
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102 assoc1 : { c₁ c₂ ℓ : Level} (A : Category c₁ c₂ ℓ) {a b c d : Obj A } {f : Hom A c d} {g : Hom A b c} {h : Hom A a b} |
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103 → A [ A [ f o ( A [ g o h ] ) ] ≈ A [ ( A [ f o g ] ) o h ] ] |
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104 assoc1 A = IsCategory.associative (Category.isCategory A) |
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105 |
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106 distr : { c₁ c₂ ℓ : Level} {A : Category c₁ c₂ ℓ} |
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107 { c₁′ c₂′ ℓ′ : Level} {D : Category c₁′ c₂′ ℓ′} (T : Functor D A) → {a b c : Obj D} {g : Hom D b c} { f : Hom D a b } |
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108 → A [ FMap T ( D [ g o f ] ) ≈ A [ FMap T g o FMap T f ] ] |
| 75 | 109 distr T = IsFunctor.distr ( isFunctor T ) |
| 110 | |
| 111 resp : {a b c : Obj A} {f g : Hom A a b} {h i : Hom A b c} → f ≈ g → h ≈ i → (h o f) ≈ (i o g) | |
| 112 resp = IsCategory.o-resp-≈ (Category.isCategory A) | |
| 113 | |
| 114 fcong : { c₁ c₂ ℓ : Level} {C : Category c₁ c₂ ℓ} | |
| 115 { c₁′ c₂′ ℓ′ : Level} {D : Category c₁′ c₂′ ℓ′} {a b : Obj C} {f g : Hom C a b} → (T : Functor C D) → C [ f ≈ g ] → D [ FMap T f ≈ FMap T g ] | |
| 116 fcong T = IsFunctor.≈-cong (isFunctor T) | |
| 31 | 117 |
| 118 open NTrans | |
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119 nat : { c₁ c₂ ℓ : Level} {A : Category c₁ c₂ ℓ} { c₁′ c₂′ ℓ′ : Level} {D : Category c₁′ c₂′ ℓ′} |
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120 {a b : Obj D} {f : Hom D a b} {F G : Functor D A } |
| 31 | 121 → (η : NTrans D A F G ) |
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122 → A [ A [ FMap G f o TMap η a ] ≈ A [ TMap η b o FMap F f ] ] |
| 130 | 123 nat η = IsNTrans.commute ( isNTrans η ) |
| 31 | 124 |
| 152 | 125 infixr 2 _∎ |
| 31 | 126 infixr 2 _≈⟨_⟩_ _≈⟨⟩_ |
| 168 | 127 infixr 2 _≈↑⟨_⟩_ |
| 31 | 128 infix 1 begin_ |
| 129 | |
| 130 ------ If we have this, for example, as an axiom of a category, we can use ≡-Reasoning directly | |
| 131 -- ≈-to-≡ : {a b : Obj A } { x y : Hom A a b } → A [ x ≈ y ] → x ≡ y | |
| 132 -- ≈-to-≡ refl-hom = refl | |
| 133 | |
| 134 data _IsRelatedTo_ { a b : Obj A } ( x y : Hom A a b ) : | |
| 135 Set (suc (c₁ ⊔ c₂ ⊔ ℓ )) where | |
| 136 relTo : (x≈y : x ≈ y ) → x IsRelatedTo y | |
| 137 | |
| 138 begin_ : { a b : Obj A } { x y : Hom A a b } → | |
| 139 x IsRelatedTo y → x ≈ y | |
| 140 begin relTo x≈y = x≈y | |
| 141 | |
| 142 _≈⟨_⟩_ : { a b : Obj A } ( x : Hom A a b ) → { y z : Hom A a b } → | |
| 143 x ≈ y → y IsRelatedTo z → x IsRelatedTo z | |
| 144 _ ≈⟨ x≈y ⟩ relTo y≈z = relTo (trans-hom x≈y y≈z) | |
| 145 | |
| 168 | 146 _≈↑⟨_⟩_ : { a b : Obj A } ( x : Hom A a b ) → { y z : Hom A a b } → |
| 147 y ≈ x → y IsRelatedTo z → x IsRelatedTo z | |
| 148 _ ≈↑⟨ y≈x ⟩ relTo y≈z = relTo (trans-hom ( sym y≈x ) y≈z) | |
| 149 | |
| 31 | 150 _≈⟨⟩_ : { a b : Obj A } ( x : Hom A a b ) → { y : Hom A a b } → x IsRelatedTo y → x IsRelatedTo y |
| 151 _ ≈⟨⟩ x∼y = x∼y | |
| 152 | |
| 153 _∎ : { a b : Obj A } ( x : Hom A a b ) → x IsRelatedTo x | |
| 154 _∎ _ = relTo refl-hom | |
| 155 | |
| 56 | 156 -- an example |
| 157 | |
| 158 Lemma61 : {c₁ c₂ ℓ : Level} (A : Category c₁ c₂ ℓ) → | |
| 159 { a : Obj A } ( b : Obj A ) → | |
| 160 ( f : Hom A a b ) | |
| 161 → A [ A [ (Id {_} {_} {_} {A} b) o f ] ≈ f ] | |
| 162 Lemma61 c b g = -- IsCategory.identityL (Category.isCategory c) | |
| 163 let open ≈-Reasoning (c) in | |
| 164 begin | |
| 165 c [ Id {_} {_} {_} {c} b o g ] | |
| 166 ≈⟨ IsCategory.identityL (Category.isCategory c) ⟩ | |
| 167 g | |
| 168 ∎ | |
| 253 | 169 |
| 170 Lemma62 : {c₁ c₂ ℓ : Level} (A : Category c₁ c₂ ℓ) → | |
| 171 { a b : Obj A } → | |
| 172 ( f g : Hom A a b ) | |
| 173 → A [ A [ (Id {_} {_} {_} {A} b) o f ] ≈ A [ (Id {_} {_} {_} {A} b) o g ] ] | |
| 174 → A [ g ≈ f ] | |
| 175 Lemma62 A {a} {b} f g 1g=1f = let open ≈-Reasoning A in | |
| 176 begin | |
| 177 g | |
| 178 ≈↑⟨ idL ⟩ | |
| 179 id b o g | |
| 180 ≈↑⟨ 1g=1f ⟩ | |
| 181 id b o f | |
| 182 ≈⟨ idL ⟩ | |
| 183 f | |
| 184 ∎ |