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Mathlib.RepresentationTheory.Action.Monoidal

Induced monoidal structure on Action V G #

We show:

@[simp]
theorem Action.instMonoidalCategory_tensorHom_hom {V : Type (u + 1)} [CategoryTheory.LargeCategory V] {G : MonCat} [CategoryTheory.MonoidalCategory V] {X₁✝ Y₁✝ X₂✝ Y₂✝ : Action V G} (f : X₁✝ Y₁✝) (g : X₂✝ Y₂✝) :
@[simp]
@[simp]
def Action.tensorUnitIso {V : Type (u + 1)} [CategoryTheory.LargeCategory V] {G : MonCat} [CategoryTheory.MonoidalCategory V] {X : V} (f : 𝟙_ V X) :
𝟙_ (Action V G) { V := X, ρ := 1 }

Given an object X isomorphic to the tensor unit of V, X equipped with the trivial action is isomorphic to the tensor unit of Action V G.

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    When V is braided the forgetful functor Action V G to V is braided.

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    instance Action.instMonoidalFunctorSingleObjαMonoidFunctor (V : Type (u + 1)) [CategoryTheory.LargeCategory V] (G : MonCat) [CategoryTheory.MonoidalCategory V] :
    Action.FunctorCategoryEquivalence.functor.Monoidal

    Upgrading the functor Action V G ⥤ (SingleObj G ⥤ V) to a monoidal functor.

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    instance Action.instMonoidalFunctorSingleObjαMonoidInverse (V : Type (u + 1)) [CategoryTheory.LargeCategory V] (G : MonCat) [CategoryTheory.MonoidalCategory V] :
    Action.FunctorCategoryEquivalence.inverse.Monoidal

    Upgrading the functor (SingleObj G ⥤ V) ⥤ Action V G to a monoidal functor.

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    theorem Action.FunctorCategoryEquivalence.functor_η (V : Type (u + 1)) [CategoryTheory.LargeCategory V] (G : MonCat) [CategoryTheory.MonoidalCategory V] :
    CategoryTheory.Functor.OplaxMonoidal.η Action.FunctorCategoryEquivalence.functor = CategoryTheory.CategoryStruct.id (Action.FunctorCategoryEquivalence.functor.obj (𝟙_ (Action V G)))
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    theorem Action.FunctorCategoryEquivalence.functor_μ (V : Type (u + 1)) [CategoryTheory.LargeCategory V] (G : MonCat) [CategoryTheory.MonoidalCategory V] (A B : Action V G) :
    CategoryTheory.Functor.LaxMonoidal.μ Action.FunctorCategoryEquivalence.functor A B = CategoryTheory.CategoryStruct.id (CategoryTheory.MonoidalCategory.tensorObj (Action.FunctorCategoryEquivalence.functor.obj A) (Action.FunctorCategoryEquivalence.functor.obj B))
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    theorem Action.FunctorCategoryEquivalence.functor_δ (V : Type (u + 1)) [CategoryTheory.LargeCategory V] (G : MonCat) [CategoryTheory.MonoidalCategory V] (A B : Action V G) :
    CategoryTheory.Functor.OplaxMonoidal.δ Action.FunctorCategoryEquivalence.functor A B = CategoryTheory.CategoryStruct.id (Action.FunctorCategoryEquivalence.functor.obj (CategoryTheory.MonoidalCategory.tensorObj A B))

    If V is right rigid, so is Action V G.

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    If V is left rigid, so is Action V G.

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    Given X : Action (Type u) (MonCat.of G) for G a group, then G × X (with G acting as left multiplication on the first factor and by X.ρ on the second) is isomorphic as a G-set to G × X (with G acting as left multiplication on the first factor and trivially on the second). The isomorphism is given by (g, x) ↦ (g, g⁻¹ • x).

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      theorem Action.leftRegularTensorIso_inv_hom (G : Type u) [Group G] (X : Action (Type u) (MonCat.of G)) (g : (CategoryTheory.MonoidalCategory.tensorObj (Action.leftRegular G) { V := X.V, ρ := 1 }).V) :
      (Action.leftRegularTensorIso G X).inv.hom g = (g.1, X g.1 g.2)

      The natural isomorphism of G-sets Gⁿ⁺¹ ≅ G × Gⁿ, where G acts by left multiplication on each factor.

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        theorem Action.diagonalSucc_inv_hom (G : Type u) [Monoid G] (n : ) (a✝ : (CategoryTheory.MonoidalCategory.tensorObj (Action.leftRegular G) (Action.diagonal G n)).V) :
        (Action.diagonalSucc G n).inv.hom a✝ = (Fin.consEquiv fun (a : Fin (n + 1)) => G) a✝
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        theorem Action.diagonalSucc_hom_hom (G : Type u) [Monoid G] (n : ) (a✝ : (Action.diagonal G (n + 1)).V) :
        (Action.diagonalSucc G n).hom.hom a✝ = (Fin.consEquiv fun (a : Fin (n + 1)) => G).symm a✝

        A lax monoidal functor induces a lax monoidal functor between the categories of G-actions within those categories.

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        An oplax monoidal functor induces an oplax monoidal functor between the categories of G-actions within those categories.

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        A monoidal functor induces a monoidal functor between the categories of G-actions within those categories.

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