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Mathlib.CategoryTheory.Monoidal.Skeleton

The monoid on the skeleton of a monoidal category #

The skeleton of a monoidal category is a monoid.

Main results #

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@[reducible, inline]
abbrev CategoryTheory.monoidOfSkeletalMonoidal {C : Type u} [Category.{v, u} C] [MonoidalCategory C] (hC : Skeletal C) :
Monoid C

If C is monoidal and skeletal, it is a monoid. See note [reducible non-instances].

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    def CategoryTheory.commMonoidOfSkeletalBraided {C : Type u} [Category.{v, u} C] [MonoidalCategory C] [BraidedCategory C] (hC : Skeletal C) :
    CommMonoid C

    If C is braided and skeletal, it is a commutative monoid.

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      noncomputable instance CategoryTheory.Skeleton.instMonoidalCategory {C : Type u} [Category.{v, u} C] [MonoidalCategory C] :
      MonoidalCategory (Skeleton C)

      The skeleton of a monoidal category has a monoidal structure itself, induced by the equivalence.

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      noncomputable instance CategoryTheory.Skeleton.instMonoid {C : Type u} [Category.{v, u} C] [MonoidalCategory C] :
      Monoid (Skeleton C)

      The skeleton of a monoidal category can be viewed as a monoid, where the multiplication is given by the tensor product, and satisfies the monoid axioms since it is a skeleton.

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      theorem CategoryTheory.Skeleton.mul_eq {C : Type u} [Category.{v, u} C] [MonoidalCategory C] (X Y : Skeleton C) :
      X * Y = toSkeleton (MonoidalCategoryStruct.tensorObj (Quotient.out X) (Quotient.out Y))
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      theorem CategoryTheory.Skeleton.one_eq {C : Type u} [Category.{v, u} C] [MonoidalCategory C] :
      1 = toSkeleton (𝟙_ C)
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      theorem CategoryTheory.Skeleton.toSkeleton_tensorObj {C : Type u} [Category.{v, u} C] [MonoidalCategory C] (X Y : C) :
      toSkeleton (MonoidalCategoryStruct.tensorObj X Y) = toSkeleton X * toSkeleton Y
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      noncomputable instance CategoryTheory.Skeleton.instBraidedCategory {C : Type u} [Category.{v, u} C] [MonoidalCategory C] [BraidedCategory C] :
      BraidedCategory (Skeleton C)

      The skeleton of a braided monoidal category has a braided monoidal structure itself, induced by the equivalence.

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      noncomputable instance CategoryTheory.Skeleton.instCommMonoid {C : Type u} [Category.{v, u} C] [MonoidalCategory C] [BraidedCategory C] :
      CommMonoid (Skeleton C)

      The skeleton of a braided monoidal category can be viewed as a commutative monoid, where the multiplication is given by the tensor product, and satisfies the monoid axioms since it is a skeleton.

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