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Mathlib.CategoryTheory.Action.Monoidal

Induced monoidal structure on Action V G #

We show:

@[simp]
theorem Action.tensorHom_hom {V : Type u_1} [CategoryTheory.Category.{u_3, u_1} V] {G : Type u_2} [Monoid G] [CategoryTheory.MonoidalCategory V] {X₁✝ Y₁✝ X₂✝ Y₂✝ : Action V G} (f : X₁✝ Y₁✝) (g : X₂✝ Y₂✝) :

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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    Given X : Action (Type u) 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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      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_hom_hom (G : Type u_3) [Monoid G] (n : ) (a✝ : (diagonal G (n + 1)).V) :
        (diagonalSucc G n).hom.hom a✝ = (Fin.consEquiv fun (a : Fin (n + 1)) => G).symm a✝
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        theorem Action.diagonalSucc_inv_hom (G : Type u_3) [Monoid G] (n : ) (a✝ : (CategoryTheory.MonoidalCategoryStruct.tensorObj (leftRegular G) (diagonal G n)).V) :
        (diagonalSucc G n).inv.hom a✝ = (Fin.consEquiv fun (a : Fin (n + 1)) => G) 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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