mathlib3 documentation

category_theory.monoidal.preadditive

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.

@[class]
  • 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.

Instances of this typeclass
theorem category_theory.tensor_sum {C : Type u_1} [category_theory.category C] [category_theory.preadditive C] [category_theory.monoidal_category C] [category_theory.monoidal_preadditive C] {P Q R S : C} {J : Type u_3} (s : finset J) (f : P ⟶ Q) (g : J → (R ⟶ S)) :
f ⊗ s.sum (λ (j : J), g j) = s.sum (λ (j : J), f ⊗ g j)
theorem category_theory.sum_tensor {C : Type u_1} [category_theory.category C] [category_theory.preadditive C] [category_theory.monoidal_category C] [category_theory.monoidal_preadditive C] {P Q R S : C} {J : Type u_3} (s : finset J) (f : P ⟶ Q) (g : J → (R ⟶ S)) :
s.sum (λ (j : J), g j) ⊗ f = s.sum (λ (j : J), g j ⊗ f)

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.

Equations