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Mathlib.AlgebraicTopology.SimplicialSet.Monoidal

The monoidal category structure on simplicial sets #

This file defines an instance of chosen finite products for the category SSet. It follows from the fact the SSet if a category of functors to the category of types and that the category of types have chosen finite products. As a result, we obtain a monoidal category structure on SSet.

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instance SSet.instCartesianMonoidalCategory :
CategoryTheory.CartesianMonoidalCategory SSet
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instance SSet.instMonoidalClosed :
CategoryTheory.MonoidalClosed SSet
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theorem SSet.leftUnitor_hom_app_apply (K : SSet) {Δ : SimplexCategoryᵒᵖ} (x : (CategoryTheory.MonoidalCategoryStruct.tensorObj (CategoryTheory.MonoidalCategoryStruct.tensorUnit SSet) K).obj Δ) :
(CategoryTheory.MonoidalCategoryStruct.leftUnitor K).hom.app Δ x = x.2
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@[simp]
theorem SSet.leftUnitor_inv_app_apply (K : SSet) {Δ : SimplexCategoryᵒᵖ} (x : K.obj Δ) :
(CategoryTheory.MonoidalCategoryStruct.leftUnitor K).inv.app Δ x = (PUnit.unit, x)
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theorem SSet.rightUnitor_hom_app_apply (K : SSet) {Δ : SimplexCategoryᵒᵖ} (x : (CategoryTheory.MonoidalCategoryStruct.tensorObj K (CategoryTheory.MonoidalCategoryStruct.tensorUnit SSet)).obj Δ) :
(CategoryTheory.MonoidalCategoryStruct.rightUnitor K).hom.app Δ x = x.1
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theorem SSet.rightUnitor_inv_app_apply (K : SSet) {Δ : SimplexCategoryᵒᵖ} (x : K.obj Δ) :
(CategoryTheory.MonoidalCategoryStruct.rightUnitor K).inv.app Δ x = (x, PUnit.unit)
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@[simp]
theorem SSet.tensorHom_app_apply {K K' L L' : SSet} (f : K ⟶ K') (g : L ⟶ L') {Δ : SimplexCategoryᵒᵖ} (x : (CategoryTheory.MonoidalCategoryStruct.tensorObj K L).obj Δ) :
(CategoryTheory.MonoidalCategoryStruct.tensorHom f g).app Δ x = (f.app Δ x.1, g.app Δ x.2)
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theorem SSet.whiskerLeft_app_apply (K : SSet) {L L' : SSet} (g : L ⟶ L') {Δ : SimplexCategoryᵒᵖ} (x : (CategoryTheory.MonoidalCategoryStruct.tensorObj K L).obj Δ) :
(CategoryTheory.MonoidalCategoryStruct.whiskerLeft K g).app Δ x = (x.1, g.app Δ x.2)
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theorem SSet.whiskerRight_app_apply {K K' : SSet} (f : K ⟶ K') (L : SSet) {Δ : SimplexCategoryᵒᵖ} (x : (CategoryTheory.MonoidalCategoryStruct.tensorObj K L).obj Δ) :
(CategoryTheory.MonoidalCategoryStruct.whiskerRight f L).app Δ x = (f.app Δ x.1, x.2)
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theorem SSet.associator_hom_app_apply (K L M : SSet) {Δ : SimplexCategoryᵒᵖ} (x : (CategoryTheory.MonoidalCategoryStruct.tensorObj (CategoryTheory.MonoidalCategoryStruct.tensorObj K L) M).obj Δ) :
(CategoryTheory.MonoidalCategoryStruct.associator K L M).hom.app Δ x = (x.1.1, x.1.2, x.2)
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theorem SSet.associator_inv_app_apply (K L M : SSet) {Δ : SimplexCategoryᵒᵖ} (x : (CategoryTheory.MonoidalCategoryStruct.tensorObj K (CategoryTheory.MonoidalCategoryStruct.tensorObj L M)).obj Δ) :
(CategoryTheory.MonoidalCategoryStruct.associator K L M).inv.app Δ x = ((x.1, x.2.1), x.2.2)
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def SSet.unitHomEquiv (K : SSet) :
(CategoryTheory.MonoidalCategoryStruct.tensorUnit SSet ⟶ K) ≃ K.obj (Opposite.op (SimplexCategory.mk 0))

The bijection (𝟙_ SSet ⟶ K) ≃ K _⦋0⦌.

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  • One or more equations did not get rendered due to their size.
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    def SSet.stdSimplex.isTerminalObj₀ :
    CategoryTheory.Limits.IsTerminal (stdSimplex.obj (SimplexCategory.mk 0))

    The object Δ[0] is terminal in SSet.

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      theorem SSet.stdSimplex.ext₀ {X : SSet} {f g : X ⟶ stdSimplex.obj (SimplexCategory.mk 0)} :
      f = g
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      theorem SSet.stdSimplex.ext₀_iff {X : SSet} {f g : X ⟶ stdSimplex.obj (SimplexCategory.mk 0)} :
      f = g ↔ True
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      instance SSet.instFiniteObjOppositeSimplexCategoryTensorObj (X Y : SSet) (n : SimplexCategoryᵒᵖ) [Finite (X.obj n)] [Finite (Y.obj n)] :
      Finite ((CategoryTheory.MonoidalCategoryStruct.tensorObj X Y).obj n)
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      instance SSet.instFiniteTensorUnit :
      (CategoryTheory.MonoidalCategoryStruct.tensorUnit SSet).Finite
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      instance SSet.instHasDimensionLETensorUnitOfNatNat :
      (CategoryTheory.MonoidalCategoryStruct.tensorUnit SSet).HasDimensionLE 0
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      def SSet.Subcomplex.prod {X Y : SSet} (A : X.Subcomplex) (B : Y.Subcomplex) :
      (CategoryTheory.MonoidalCategoryStruct.tensorObj X Y).Subcomplex

      The external product of subcomplexes of simplicial sets.

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        theorem SSet.Subcomplex.prod_obj {X Y : SSet} (A : X.Subcomplex) (B : Y.Subcomplex) (Δ : SimplexCategoryᵒᵖ) :
        (A.prod B).obj Δ = (A.obj Δ).prod (B.obj Δ)
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        theorem SSet.Subcomplex.prod_monotone {X Y : SSet} {A₁ A₂ : X.Subcomplex} (hX : A₁ ≤ A₂) {B₁ B₂ : Y.Subcomplex} (hY : B₁ ≤ B₂) :
        A₁.prod B₁ ≤ A₂.prod B₂
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        theorem SSet.Subcomplex.range_tensorHom {X₁ X₂ Y₁ Y₂ : SSet} (f₁ : X₁ ⟶ Y₁) (f₂ : X₂ ⟶ Y₂) :
        range (CategoryTheory.MonoidalCategoryStruct.tensorHom f₁ f₂) = (range f₁).prod (range f₂)
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        noncomputable def SSet.ι₀ {X : SSet} :
        X ⟶ CategoryTheory.MonoidalCategoryStruct.tensorObj X (stdSimplex.obj (SimplexCategory.mk 1))

        The inclusion X ⟶ X ⊗ Δ[1] which is 0 on the second factor.

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          theorem SSet.ι₀_comp {X Y : SSet} (f : X ⟶ Y) :
          CategoryTheory.CategoryStruct.comp ι₀ (CategoryTheory.MonoidalCategoryStruct.whiskerRight f (stdSimplex.obj (SimplexCategory.mk 1))) = CategoryTheory.CategoryStruct.comp f ι₀
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          theorem SSet.ι₀_comp_assoc {X Y : SSet} (f : X ⟶ Y) {Z : SSet} (h : CategoryTheory.MonoidalCategoryStruct.tensorObj Y (stdSimplex.obj (SimplexCategory.mk 1)) ⟶ Z) :
          CategoryTheory.CategoryStruct.comp ι₀ (CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.whiskerRight f (stdSimplex.obj (SimplexCategory.mk 1))) h) = CategoryTheory.CategoryStruct.comp f (CategoryTheory.CategoryStruct.comp ι₀ h)
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          theorem SSet.ι₀_fst (X : SSet) :
          CategoryTheory.CategoryStruct.comp ι₀ (CategoryTheory.SemiCartesianMonoidalCategory.fst X (stdSimplex.obj (SimplexCategory.mk 1))) = CategoryTheory.CategoryStruct.id X
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          theorem SSet.ι₀_fst_assoc (X : SSet) {Z : SSet} (h : X ⟶ Z) :
          CategoryTheory.CategoryStruct.comp ι₀ (CategoryTheory.CategoryStruct.comp (CategoryTheory.SemiCartesianMonoidalCategory.fst X (stdSimplex.obj (SimplexCategory.mk 1))) h) = h
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          theorem SSet.ι₀_snd (X : SSet) :
          CategoryTheory.CategoryStruct.comp ι₀ (CategoryTheory.SemiCartesianMonoidalCategory.snd X (stdSimplex.obj (SimplexCategory.mk 1))) = const (stdSimplex.obj₀Equiv.symm 0)
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          theorem SSet.ι₀_snd_assoc (X : SSet) {Z : SSet} (h : stdSimplex.obj (SimplexCategory.mk 1) ⟶ Z) :
          CategoryTheory.CategoryStruct.comp ι₀ (CategoryTheory.CategoryStruct.comp (CategoryTheory.SemiCartesianMonoidalCategory.snd X (stdSimplex.obj (SimplexCategory.mk 1))) h) = CategoryTheory.CategoryStruct.comp (const (stdSimplex.obj₀Equiv.symm 0)) h
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          theorem SSet.ι₀_app_fst {X : SSet} {m : SimplexCategoryᵒᵖ} (x : X.obj m) :
          (ι₀.app m x).1 = x
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          noncomputable def SSet.ι₁ {X : SSet} :
          X ⟶ CategoryTheory.MonoidalCategoryStruct.tensorObj X (stdSimplex.obj (SimplexCategory.mk 1))

          The inclusion X ⟶ X ⊗ Δ[1] which is 1 on the second factor.

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            theorem SSet.ι₁_fst (X : SSet) :
            CategoryTheory.CategoryStruct.comp ι₁ (CategoryTheory.SemiCartesianMonoidalCategory.fst X (stdSimplex.obj (SimplexCategory.mk 1))) = CategoryTheory.CategoryStruct.id X
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            theorem SSet.ι₁_fst_assoc (X : SSet) {Z : SSet} (h : X ⟶ Z) :
            CategoryTheory.CategoryStruct.comp ι₁ (CategoryTheory.CategoryStruct.comp (CategoryTheory.SemiCartesianMonoidalCategory.fst X (stdSimplex.obj (SimplexCategory.mk 1))) h) = h
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            theorem SSet.ι₁_snd (X : SSet) :
            CategoryTheory.CategoryStruct.comp ι₁ (CategoryTheory.SemiCartesianMonoidalCategory.snd X (stdSimplex.obj (SimplexCategory.mk 1))) = const (stdSimplex.obj₀Equiv.symm 1)
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            theorem SSet.ι₁_snd_assoc (X : SSet) {Z : SSet} (h : stdSimplex.obj (SimplexCategory.mk 1) ⟶ Z) :
            CategoryTheory.CategoryStruct.comp ι₁ (CategoryTheory.CategoryStruct.comp (CategoryTheory.SemiCartesianMonoidalCategory.snd X (stdSimplex.obj (SimplexCategory.mk 1))) h) = CategoryTheory.CategoryStruct.comp (const (stdSimplex.obj₀Equiv.symm 1)) h
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            theorem SSet.ι₁_comp {X Y : SSet} (f : X ⟶ Y) :
            CategoryTheory.CategoryStruct.comp ι₁ (CategoryTheory.MonoidalCategoryStruct.whiskerRight f (stdSimplex.obj (SimplexCategory.mk 1))) = CategoryTheory.CategoryStruct.comp f ι₁
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            theorem SSet.ι₁_comp_assoc {X Y : SSet} (f : X ⟶ Y) {Z : SSet} (h : CategoryTheory.MonoidalCategoryStruct.tensorObj Y (stdSimplex.obj (SimplexCategory.mk 1)) ⟶ Z) :
            CategoryTheory.CategoryStruct.comp ι₁ (CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.whiskerRight f (stdSimplex.obj (SimplexCategory.mk 1))) h) = CategoryTheory.CategoryStruct.comp f (CategoryTheory.CategoryStruct.comp ι₁ h)
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            theorem SSet.ι₁_app_fst {X : SSet} {m : SimplexCategoryᵒᵖ} (x : X.obj m) :
            (ι₁.app m x).1 = x
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            instance SSet.Truncated.instCartesianMonoidalCategory (n : ℕ) :
            CategoryTheory.CartesianMonoidalCategory (Truncated n)
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            instance SSet.Truncated.instMonoidalClosed (n : ℕ) :
            CategoryTheory.MonoidalClosed (Truncated n)
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            instance SSet.Truncated.instMonoidalTruncation (n : ℕ) :
            (truncation n).Monoidal
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            theorem SSet.Truncated.tensor_map_apply_fst {n : ℕ} {X Y : Truncated n} {d e : (SimplexCategory.Truncated n)ᵒᵖ} (f : d ⟶ e) (x : (CategoryTheory.MonoidalCategoryStruct.tensorObj X Y).obj d) :
            ((CategoryTheory.MonoidalCategoryStruct.tensorObj X Y).map f x).1 = X.map f x.1
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            theorem SSet.Truncated.tensor_map_apply_snd {n : ℕ} {X Y : Truncated n} {d e : (SimplexCategory.Truncated n)ᵒᵖ} (f : d ⟶ e) (x : (CategoryTheory.MonoidalCategoryStruct.tensorObj X Y).obj d) :
            ((CategoryTheory.MonoidalCategoryStruct.tensorObj X Y).map f x).2 = Y.map f x.2