Preadditive monoidal categories #
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A monoidal category is monoidal_preadditive
if it is preadditive and tensor product of morphisms
is linear in both factors.
- tensor_zero' : (∀ {W X Y Z : C} (f : W ⟶ X), f ⊗ 0 = 0) . "obviously"
- zero_tensor' : (∀ {W X Y Z : C} (f : Y ⟶ Z), 0 ⊗ f = 0) . "obviously"
- tensor_add' : (∀ {W X Y Z : C} (f : W ⟶ X) (g h : Y ⟶ Z), f ⊗ (g + h) = f ⊗ g + f ⊗ h) . "obviously"
- add_tensor' : (∀ {W X Y Z : C} (f g : W ⟶ X) (h : Y ⟶ Z), (f + g) ⊗ h = f ⊗ h + g ⊗ h) . "obviously"
A category is monoidal_preadditive
if tensoring is additive in both factors.
Note we don't extend preadditive C
here, as abelian C
already extends it,
and we'll need to have both typeclasses sometimes.
A faithful additive monoidal functor to a monoidal preadditive category ensures that the domain is monoidal preadditive.
Equations
- category_theory.monoidal_category.tensor_left.limits.preserves_finite_biproducts X = {preserves := λ (J : Type) (_x : fintype J), {preserves := λ (f : J → C), {preserves := λ (b : category_theory.limits.bicone f) (i : b.is_bilimit), category_theory.limits.is_bilimit_of_total ((category_theory.monoidal_category.tensor_left X).map_bicone b) _}}}
Equations
- category_theory.monoidal_category.tensor_right.limits.preserves_finite_biproducts X = {preserves := λ (J : Type) (_x : fintype J), {preserves := λ (f : J → C), {preserves := λ (b : category_theory.limits.bicone f) (i : b.is_bilimit), category_theory.limits.is_bilimit_of_total ((category_theory.monoidal_category.tensor_right X).map_bicone b) _}}}
The isomorphism showing how tensor product on the left distributes over direct sums.
Equations
The isomorphism showing how tensor product on the right distributes over direct sums.