Construction of the localized category #
This file constructs the localized category, obtained by formally inverting
a class of maps W : MorphismProperty C
in a category C
.
We first construct a quiver LocQuiver W
whose objects are the same as those
of C
and whose maps are the maps in C
and placeholders for the formal
inverses of the maps in W
.
The localized category W.Localization
is obtained by taking the quotient
of the path category of LocQuiver W
by the congruence generated by four
types of relations.
The obvious functor Q W : C ⥤ W.Localization
satisfies the universal property
of the localization. Indeed, if G : C ⥤ D
sends morphisms in W
to isomorphisms
in D
(i.e. we have hG : W.IsInvertedBy G
), then there exists a unique functor
G' : W.Localization ⥤ D
such that Q W ≫ G' = G
. This G'
is lift G hG
.
The expected property of lift G hG
if expressed by the lemma fac
and the
uniqueness is expressed by uniq
.
References #
- [P. Gabriel, M. Zisman, Calculus of fractions and homotopy theory][gabriel-zisman-1967]
If W : MorphismProperty C
, LocQuiver W
is a quiver with the same objects
as C
, and whose morphisms are those in C
and placeholders for formal
inverses of the morphisms in W
.
- obj : C
underlying object
Instances For
Equations
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The object in the path category of LocQuiver W
attached to an object in
the category C
Equations
- CategoryTheory.Localization.Construction.ιPaths W X = { obj := X }
Instances For
The morphism in the path category associated to a morphism in the original category.
Equations
- CategoryTheory.Localization.Construction.ψ₁ W f = CategoryTheory.Paths.of.map (Sum.inl f)
Instances For
The morphism in the path category corresponding to a formal inverse.
Equations
- CategoryTheory.Localization.Construction.ψ₂ W w hw = CategoryTheory.Paths.of.map (Sum.inr { val := w, property := hw })
Instances For
The relations by which we take the quotient in order to get the localized category.
- id: ∀ {C : Type uC} [inst : CategoryTheory.Category.{uC', uC} C] {W : CategoryTheory.MorphismProperty C} (X : C), CategoryTheory.Localization.Construction.relations W (CategoryTheory.Localization.Construction.ψ₁ W (CategoryTheory.CategoryStruct.id X)) (CategoryTheory.CategoryStruct.id (CategoryTheory.Localization.Construction.ιPaths W X))
- comp: ∀ {C : Type uC} [inst : CategoryTheory.Category.{uC', uC} C] {W : CategoryTheory.MorphismProperty C} {X Y Z : C} (f : X ⟶ Y) (g : Y ⟶ Z), CategoryTheory.Localization.Construction.relations W (CategoryTheory.Localization.Construction.ψ₁ W (CategoryTheory.CategoryStruct.comp f g)) (CategoryTheory.CategoryStruct.comp (CategoryTheory.Localization.Construction.ψ₁ W f) (CategoryTheory.Localization.Construction.ψ₁ W g))
- Winv₁: ∀ {C : Type uC} [inst : CategoryTheory.Category.{uC', uC} C] {W : CategoryTheory.MorphismProperty C} {X Y : C} (w : X ⟶ Y) (hw : W w), CategoryTheory.Localization.Construction.relations W (CategoryTheory.CategoryStruct.comp (CategoryTheory.Localization.Construction.ψ₁ W w) (CategoryTheory.Localization.Construction.ψ₂ W w hw)) (CategoryTheory.CategoryStruct.id (CategoryTheory.Localization.Construction.ιPaths W X))
- Winv₂: ∀ {C : Type uC} [inst : CategoryTheory.Category.{uC', uC} C] {W : CategoryTheory.MorphismProperty C} {X Y : C} (w : X ⟶ Y) (hw : W w), CategoryTheory.Localization.Construction.relations W (CategoryTheory.CategoryStruct.comp (CategoryTheory.Localization.Construction.ψ₂ W w hw) (CategoryTheory.Localization.Construction.ψ₁ W w)) (CategoryTheory.CategoryStruct.id (CategoryTheory.Localization.Construction.ιPaths W Y))
Instances For
The localized category obtained by formally inverting the morphisms
in W : MorphismProperty C
Equations
Instances For
Equations
- CategoryTheory.MorphismProperty.instCategoryLocalization W = id inferInstance
The obvious functor C ⥤ W.Localization
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Instances For
The isomorphism in W.Localization
associated to a morphism w
in W
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The formal inverse in W.Localization
of a morphism w
in W
.
Equations
Instances For
The lifting of a functor to the path category of LocQuiver W
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The lifting of a functor C ⥤ D
inverting W
as a functor W.Localization ⥤ D
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The canonical bijection between objects in a category and its
localization with respect to a morphism_property W
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Instances For
A MorphismProperty
in W.Localization
is satisfied by all
morphisms in the localized category if it contains the image of the
morphisms in the original category, the inverses of the morphisms
in W
and if it is stable under composition
A MorphismProperty
in W.Localization
is satisfied by all
morphisms in the localized category if it contains the image of the
morphisms in the original category, if is stable under composition
and if the property is stable by passing to inverses.
If F₁
and F₂
are functors W.Localization ⥤ D
and if we have
τ : W.Q ⋙ F₁ ⟶ W.Q ⋙ F₂
, we shall define a natural transformation F₁ ⟶ F₂
.
This is the app
field of this natural transformation.
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Instances For
If F₁
and F₂
are functors W.Localization ⥤ D
, a natural transformation F₁ ⟶ F₂
can be obtained from a natural transformation W.Q ⋙ F₁ ⟶ W.Q ⋙ F₂
.
Equations
Instances For
The functor (W.Localization ⥤ D) ⥤ (W.FunctorsInverting D)
induced by the
composition with W.Q : C ⥤ W.Localization
.
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Instances For
The function (W.FunctorsInverting D) ⥤ (W.Localization ⥤ D)
induced by
Construction.lift
.
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Instances For
The unit isomorphism of the equivalence of categories whiskeringLeftEquivalence W D
.
Equations
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Instances For
The counit isomorphism of the equivalence of categories WhiskeringLeftEquivalence W D
.
Equations
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Instances For
The equivalence of categories (W.localization ⥤ D) ≌ (W.FunctorsInverting D)
induced by the composition with W.Q : C ⥤ W.localization
.
Equations
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