Whiskerings, associators and unitors under a lawful Day convolution structure #
For a lawful Day convolution monoidal structure on D, Mathlib proves that the faithful functor
ι : D ⥤ C ⥤ V carries tensor products of morphisms and associators to their Day convolution
counterparts. This file adds the corresponding statements for left and right whiskerings and for
inverse associators. They are used to transfer the Day convolution braiding to C ⊛⥤ V.
For C ⊛⥤ V itself, we restate Mathlib's characterisations of the whiskerings, the tensor
product of morphisms, the associator and the unitors along the Day convolution units η F G and
ν C V, in a form simp can use, and prove that morphisms out of (F ⊗ G) ⊗ H, 𝟙_ ⊗ F and
F ⊗ 𝟙_ are determined by their restrictions along these units.
Main statements #
LawfulDayConvolutionMonoidalCategoryStruct.ι_map_whiskerLeft_eq_tensorHomandLawfulDayConvolutionMonoidalCategoryStruct.ι_map_whiskerRight_eq_tensorHom:ιcarries whiskerings to Day convolutions with an identity.LawfulDayConvolutionMonoidalCategoryStruct.ι_map_associator_inv_eq_associator_inv:ιcarries the inverse associator to the inverse Day convolution associator.DayFunctor.tensor_tensor_hom_ext,DayFunctor.unit_tensor_hom_ext,DayFunctor.tensor_unit_hom_ext: extensionality for morphisms out of iterated Day convolutions.
ι carries a left whiskering d ◁ f to the Day convolution of 𝟙 and ι.map f.
ι carries a right whiskering f ▷ d'' to the Day convolution of ι.map f and 𝟙.
ι carries the inverse associator to the inverse Day convolution associator.
The monoidal structure along the Day convolution units #
The left whiskering F ◁ g restricted along the Day convolution unit η F G.
The left whiskering F ◁ g restricted along the Day convolution unit η F G.
The right whiskering f ▷ G restricted along the Day convolution unit η F G.
The right whiskering f ▷ G restricted along the Day convolution unit η F G.
The tensor product f ⊗ₘ g restricted along the Day convolution unit η F G.
The tensor product f ⊗ₘ g restricted along the Day convolution unit η F G.
The associator (F ⊗ G) ⊗ H ≅ F ⊗ G ⊗ H restricted along the Day convolution units: at
(x, y, z) it is the associator of V, followed by the units and the action of
F ⊗ G ⊗ H on the inverse associator of C.
The associator (F ⊗ G) ⊗ H ≅ F ⊗ G ⊗ H restricted along the Day convolution units: at
(x, y, z) it is the associator of V, followed by the units and the action of
F ⊗ G ⊗ H on the inverse associator of C.
The inverse associator restricted along two Day convolution units regroups the three factors by the inverse pointwise associator.
The inverse associator restricted along two Day convolution units regroups the three factors by the inverse pointwise associator.
The left unitor 𝟙_ ⊗ F ≅ F restricted along the Day convolution units.
The left unitor 𝟙_ ⊗ F ≅ F restricted along the Day convolution units.
The right unitor F ⊗ 𝟙_ ≅ F restricted along the Day convolution units.
The right unitor F ⊗ 𝟙_ ≅ F restricted along the Day convolution units.
Morphisms out of 𝟙_ ⊗ F are determined by their restrictions along ν C V and the Day
convolution unit η (𝟙_ _) F.
Morphisms out of F ⊗ 𝟙_ are determined by their restrictions along ν C V and the Day
convolution unit η F (𝟙_ _).
Morphisms out of (F ⊗ G) ⊗ H are determined by their restrictions along the Day
convolution units η F G and η (F ⊗ G) H.