Day functors #
In this file, given a monoidal category C and a monoidal category V,
we define a basic type synonym DayFunctor C V (denoted C ⊛⥤ D)
for the category C ⥤ V and endow it with the monoidal structure coming
from Day convolution. Such a setup is necessary as by default,
the MonoidalCategory instance on C ⥤ V is the "pointwise" one,
where the tensor product of F and G is the functor x ↦ F.obj x ⊗ G.obj x.
TODOs #
- Given a
LawfulDayConvolutionMonoidalCategoryStruct C V D, show that ι induces a monoidal functorD ⥤ (C ⊛⥤ V). - Specialize to the case
V := Type _, and prove a universal property stating that for every monoidal categoryWwith suitable colimits, colimit-preserving monoidal functors(Cᵒᵖ ⊛⥤ Type u) ⥤ Ware equivalent to monoidal functorsC ⥤ W. Show that the Yoneda embedding is monoidal.
DayFunctor C V is a type synonym for C ⥤ V, implemented as a one-field
structure.
- functor : Functor C V
the underlying functor.
Instances For
Morphisms of Day functors are natural transformations of the underlying functors.
the underlying natural transformation
Instances For
Equations
The tautological equivalence of categories between C ⥤ V and C ⊛⥤ V.
Equations
Instances For
Equations
Equations
The unit transformation exhibiting (F ⊗ G).functor as a left Kan extension of
F.functor ⊠ G.functor along tensor C.
Equations
Instances For
A natural transformation F.functor ⊠ G.functor ⟶ tensor C ⋙ H.functor
defines a morphism F ⨂ G ⟶ H.
Equations
Instances For
An abstract isomorphism between (F ⊗ G).functor and the generic pointwise
left Kan extension of F.functor ⊠ G.functor along the
Equations
Instances For
The canonical map 𝟙_ V ⟶ (𝟙_ (C ⊛⥤ V)).functor.obj (𝟙_ C)
that exhibits (𝟙_ (C ⊛⥤ V)).functor as a Day convolution unit.
Equations
Instances For
The reinterpretation of ν as a natural transformation.
Equations
Instances For
Given F : C ⊛⥤ V, a morphism 𝟙_ V ⟶ F.functor.obj (𝟙_ C) induces a
(unique) morphism 𝟙_ (C ⊛⥤ V) ⟶ F.