Pseudofunctors #
A pseudofunctor is an oplax (or lax) functor whose mapId and mapComp are isomorphisms.
We provide several constructors for pseudofunctors:
Pseudofunctor.mk: the default constructor, which requiresmap₂_whiskerLeftandmap₂_whiskerRightinstead of naturality ofmapComp.Pseudofunctor.mkOfOplax: construct a pseudofunctor from an oplax functor whosemapIdandmapCompare isomorphisms. This constructor usesIsoto describe isomorphisms.pseudofunctor.mkOfOplax': similar tomkOfOplax, but usesIsIsoto describe isomorphisms.Pseudofunctor.mkOfLax: construct a pseudofunctor from a lax functor whosemapIdandmapCompare isomorphisms. This constructor usesIsoto describe isomorphisms.pseudofunctor.mkOfLax': similar tomkOfLax, but usesIsIsoto describe isomorphisms.
Main definitions #
CategoryTheory.Pseudofunctor B C: a pseudofunctor between bicategoriesBandCCategoryTheory.Pseudofunctor.comp F G: the composition of pseudofunctors
A pseudofunctor F between bicategories B and C consists of a function between objects
F.obj, a function between 1-morphisms F.map, and a function between 2-morphisms F.map₂.
Unlike functors between categories, F.map do not need to strictly commute with the compositions,
and do not need to strictly preserve the identity. Instead, there are specified 2-isomorphisms
F.map (𝟙 a) ≅ 𝟙 (F.obj a) and F.map (f ≫ g) ≅ F.map f ≫ F.map g.
F.map₂ strictly commute with compositions and preserve the identity. They also preserve the
associator, the left unitor, and the right unitor modulo some adjustments of domains and codomains
of 2-morphisms.
- obj : B → C
- map₂_comp {a b : B} {f g h : a ⟶ b} (η : f ⟶ g) (θ : g ⟶ h) : self.map₂ (CategoryStruct.comp η θ) = CategoryStruct.comp (self.map₂ η) (self.map₂ θ)
- mapComp {a b c : B} (f : a ⟶ b) (g : b ⟶ c) : self.map (CategoryStruct.comp f g) ≅ CategoryStruct.comp (self.map f) (self.map g)
- map₂_whisker_left {a b c : B} (f : a ⟶ b) {g h : b ⟶ c} (η : g ⟶ h) : self.map₂ (Bicategory.whiskerLeft f η) = CategoryStruct.comp (self.mapComp f g).hom (CategoryStruct.comp (Bicategory.whiskerLeft (self.map f) (self.map₂ η)) (self.mapComp f h).inv)
- map₂_whisker_right {a b c : B} {f g : a ⟶ b} (η : f ⟶ g) (h : b ⟶ c) : self.map₂ (Bicategory.whiskerRight η h) = CategoryStruct.comp (self.mapComp f h).hom (CategoryStruct.comp (Bicategory.whiskerRight (self.map₂ η) (self.map h)) (self.mapComp g h).inv)
- map₂_associator {a b c d : B} (f : a ⟶ b) (g : b ⟶ c) (h : c ⟶ d) : self.map₂ (Bicategory.associator f g h).hom = CategoryStruct.comp (self.mapComp (CategoryStruct.comp f g) h).hom (CategoryStruct.comp (Bicategory.whiskerRight (self.mapComp f g).hom (self.map h)) (CategoryStruct.comp (Bicategory.associator (self.map f) (self.map g) (self.map h)).hom (CategoryStruct.comp (Bicategory.whiskerLeft (self.map f) (self.mapComp g h).inv) (self.mapComp f (CategoryStruct.comp g h)).inv)))
- map₂_left_unitor {a b : B} (f : a ⟶ b) : self.map₂ (Bicategory.leftUnitor f).hom = CategoryStruct.comp (self.mapComp (CategoryStruct.id a) f).hom (CategoryStruct.comp (Bicategory.whiskerRight (self.mapId a).hom (self.map f)) (Bicategory.leftUnitor (self.map f)).hom)
- map₂_right_unitor {a b : B} (f : a ⟶ b) : self.map₂ (Bicategory.rightUnitor f).hom = CategoryStruct.comp (self.mapComp f (CategoryStruct.id b)).hom (CategoryStruct.comp (Bicategory.whiskerLeft (self.map f) (self.mapId b).hom) (Bicategory.rightUnitor (self.map f)).hom)
Instances For
The oplax functor associated with a pseudofunctor.
Equations
Instances For
Equations
The Lax functor associated with a pseudofunctor.
Equations
Instances For
Equations
The identity pseudofunctor.
Equations
Instances For
Equations
Composition of pseudofunctors.
Equations
Instances For
More flexible variant of mapId. (See the file Bicategory.Functor.Strict
for applications to strict bicategories.)
Equations
Instances For
More flexible variant of mapComp. (See Bicategory.Functor.Strict
for applications to strict bicategories.)
Equations
Instances For
Construct a pseudofunctor from an oplax functor whose mapId and mapComp are isomorphisms.
Equations
Instances For
Construct a pseudofunctor from an oplax functor whose mapId and mapComp are isomorphisms.
Equations
Instances For
Construct a pseudofunctor from a lax functor whose mapId and mapComp are isomorphisms.
Equations
Instances For
Construct a pseudofunctor from a lax functor whose mapId and mapComp are isomorphisms.