Predicate for localized categories #
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In this file, a predicate L.is_localization W
is introduced for a functor L : C ⥤ D
and W : morphism_property C
: it expresses that L
identifies D
with the localized
category of C
with respect to W
(up to equivalence).
We introduce a universal property strict_universal_property_fixed_target L W E
which
states that L
inverts the morphisms in W
and that all functors C ⥤ E
inverting
W
uniquely factors as a composition of L ⋙ G
with G : D ⥤ E
. Such universal
properties are inputs for the constructor is_localization.mk'
for L.is_localization W
.
When L : C ⥤ D
is a localization functor for W : morphism_property
(i.e. when
[L.is_localization W]
holds), for any category E
, there is
an equivalence functor_equivalence L W E : (D ⥤ E) ≌ (W.functors_inverting E)
that is induced by the composition with the functor L
. When two functors
F : C ⥤ E
and F' : D ⥤ E
correspond via this equivalence, we shall say
that F'
lifts F
, and the associated isomorphism L ⋙ F' ≅ F
is the
datum that is part of the class lifting L W F F'
. The functions
lift_nat_trans
and lift_nat_iso
can be used to lift natural transformations
and natural isomorphisms between functors.
- inverts : W.is_inverted_by L
- nonempty_is_equivalence : nonempty (category_theory.is_equivalence (category_theory.localization.construction.lift L category_theory.functor.is_localization.inverts))
The predicate expressing that, up to equivalence, a functor L : C ⥤ D
identifies the category D
with the localized category of C
with respect
to W : morphism_property C
.
- inverts : W.is_inverted_by L
- lift : Π (F : C ⥤ E), W.is_inverted_by F → D ⥤ E
- fac : ∀ (F : C ⥤ E) (hF : W.is_inverted_by F), L ⋙ self.lift F hF = F
- uniq : ∀ (F₁ F₂ : D ⥤ E), L ⋙ F₁ = L ⋙ F₂ → F₁ = F₂
This universal property states that a functor L : C ⥤ D
inverts morphisms
in W
and the all functors D ⥤ E
(for a fixed category E
) uniquely factors
through L
.
Instances for category_theory.localization.strict_universal_property_fixed_target
- category_theory.localization.strict_universal_property_fixed_target.has_sizeof_inst
- category_theory.localization.strict_universal_property_fixed_target.inhabited
The localized category W.localization
that was constructed satisfies
the universal property of the localization.
Equations
- category_theory.localization.strict_universal_property_fixed_target_Q W E = {inverts := _, lift := category_theory.localization.construction.lift _inst_3, fac := _, uniq := _}
When W
consists of isomorphisms, the identity satisfies the universal property
of the localization.
Equations
- category_theory.localization.strict_universal_property_fixed_target_id W E hW = {inverts := _, lift := λ (F : C ⥤ E) (hF : W.is_inverted_by F), F, fac := _, uniq := _}
The isomorphism L.obj X ≅ L.obj Y
that is deduced from a morphism f : X ⟶ Y
which
belongs to W
, when L.is_localization W
.
Equations
- category_theory.localization.iso_of_hom L W f hf = category_theory.as_iso (L.map f)
A chosen equivalence of categories W.localization ≅ D
for a functor
L : C ⥤ D
which satisfies L.is_localization W
. This shall be used in
order to deduce properties of L
from properties of W.Q
.
Via the equivalence of categories equivalence_from_model L W : W.localization ≌ D
,
one may identify the functors W.Q
and L
.
Via the equivalence of categories equivalence_from_model L W : W.localization ≌ D
,
one may identify the functors L
and W.Q
.
Equations
- category_theory.localization.comp_equivalence_from_model_inverse_iso L W = ((category_theory.iso_whisker_right (category_theory.localization.Q_comp_equivalence_from_model_functor_iso L W).symm (category_theory.localization.equivalence_from_model L W).inverse ≪≫ W.Q.associator (category_theory.localization.equivalence_from_model L W).functor (category_theory.localization.equivalence_from_model L W).inverse) ≪≫ category_theory.iso_whisker_left W.Q (category_theory.localization.equivalence_from_model L W).unit_iso.symm) ≪≫ W.Q.right_unitor
The functor (D ⥤ E) ⥤ W.functors_inverting E
induced by the composition
with a localization functor L : C ⥤ D
with respect to W : morphism_property C
.
Equations
- category_theory.localization.whiskering_left_functor L W E = category_theory.full_subcategory.lift (λ (F : C ⥤ E), W.is_inverted_by F) ((category_theory.whiskering_left C D E).obj L) _
Instances for category_theory.localization.whiskering_left_functor
Equations
- category_theory.localization.whiskering_left_functor.category_theory.is_equivalence L W E = category_theory.is_equivalence.of_iso (category_theory.nat_iso.of_components (λ (F : D ⥤ E), category_theory.eq_to_iso _) _) (category_theory.is_equivalence.of_equivalence ((category_theory.localization.equivalence_from_model L W).symm.congr_left.trans (category_theory.localization.construction.whiskering_left_equivalence W E)))
The equivalence of categories (D ⥤ E) ≌ (W.functors_inverting E)
induced by
the composition with a localization functor L : C ⥤ D
with respect to
W : morphism_property C
.
The functor (D ⥤ E) ⥤ (C ⥤ E)
given by the composition with a localization
functor L : C ⥤ D
with respect to W : morphism_property C
.
Equations
Instances for category_theory.localization.whiskering_left_functor'
When L : C ⥤ D
is a localization functor for W : morphism_property C
and
F : C ⥤ E
is a functor, we shall say that F' : D ⥤ E
lifts F
if the obvious diagram
is commutative up to an isomorphism.
Instances of this typeclass
Instances of other typeclasses for category_theory.localization.lifting
- category_theory.localization.lifting.has_sizeof_inst
Given a localization functor L : C ⥤ D
for W : morphism_property C
and
a functor F : C ⥤ E
which inverts W
, this is a choice of functor
D ⥤ E
which lifts F
.
Equations
- category_theory.localization.lift F hF L = (category_theory.localization.functor_equivalence L W E).inverse.obj {obj := F, property := hF}
Instances for category_theory.localization.lift
Equations
The canonical isomorphism L ⋙ lift F hF L ≅ F
for any functor F : C ⥤ E
which inverts W
, when L : C ⥤ D
is a localization functor for W
.
Equations
Equations
Given a localization functor L : C ⥤ D
for W : morphism_property C
,
if (F₁' F₂' : D ⥤ E)
are functors which lifts functors (F₁ F₂ : C ⥤ E)
,
a natural transformation τ : F₁ ⟶ F₂
uniquely lifts to a natural transformation F₁' ⟶ F₂'
.
Equations
- category_theory.localization.lift_nat_trans L W F₁ F₂ F₁' F₂' τ = (category_theory.localization.whiskering_left_functor' L W E).preimage ((category_theory.localization.lifting.iso L W F₁ F₁').hom ≫ τ ≫ (category_theory.localization.lifting.iso L W F₂ F₂').inv)
Given a localization functor L : C ⥤ D
for W : morphism_property C
,
if (F₁' F₂' : D ⥤ E)
are functors which lifts functors (F₁ F₂ : C ⥤ E)
,
a natural isomorphism τ : F₁ ⟶ F₂
lifts to a natural isomorphism F₁' ⟶ F₂'
.
Equations
- category_theory.localization.lift_nat_iso L W F₁ F₂ F₁' F₂' e = {hom := category_theory.localization.lift_nat_trans L W F₁ F₂ F₁' F₂' e.hom, inv := category_theory.localization.lift_nat_trans L W F₂ F₁ F₂' F₁' e.inv, hom_inv_id' := _, inv_hom_id' := _}
Equations
- category_theory.localization.lifting.comp_right L W F F' G = {iso := category_theory.iso_whisker_right (category_theory.localization.lifting.iso L W F F') G}
Equations
Given a localization functor L : C ⥤ D
for W : morphism_property C
,
if F₁' : D ⥤ E
lifts a functor F₁ : C ⥤ D
, then a functor F₂'
which
is isomorphic to F₁'
also lifts a functor F₂
that is isomorphic to F₁
.
Equations
- category_theory.localization.lifting.of_isos L W e e' = {iso := category_theory.iso_whisker_left L e'.symm ≪≫ category_theory.localization.lifting.iso L W F₁ F₁' ≪≫ e}
If L : C ⥤ D
is a localization for W : morphism_property C
, then it is also
the case of a functor obtained by post-composing L
with an equivalence of categories.