theorem
CategoryTheory.Functor.map_eqToHom
{C : Type u_1}
[CategoryTheory.Category.{u_3, u_1} C]
{D : Type u_2}
[CategoryTheory.Category.{u_4, u_2} D]
(F : CategoryTheory.Functor C D)
(X Y : C)
(h : X = Y)
:
F.map (CategoryTheory.eqToHom h) = CategoryTheory.eqToHom ⋯
theorem
CategoryTheory.ComposableArrows.map'_def
{C : Type u_1}
[inst : CategoryTheory.Category.{u_2, u_1} C]
{n : ℕ}
(F : CategoryTheory.ComposableArrows C n)
(i j : ℕ)
(hij : i ≤ j := by valid)
(hjn : j ≤ n := by valid)
:
F.map' i j hij hjn = F.map (CategoryTheory.homOfLE ⋯)
Kan complexes and quasicategories #
noncomputable def
SSet.nerve.mk
{C : Type u}
[inst : CategoryTheory.Category.{v, u} C]
(n : ℕ)
(obj : Fin (n + 1) → C)
(mor : (i : Fin n) → obj i.castSucc ⟶ obj i.succ)
:
(CategoryTheory.nerve C).obj (Opposite.op (SimplexCategory.mk n))
A constructor for n
-simplices of the nerve of a category,
by specifying n+1
objects and a morphism between each of the n
pairs of adjecent objects.
Equations
- SSet.nerve.mk n obj mor = CategoryTheory.ComposableArrows.mkOfObjOfMapSucc obj mor
Instances For
def
SSet.nerve.δ_mk_mor
{C : Type u}
[inst : CategoryTheory.Category.{v, u} C]
(n : ℕ)
(obj : Fin (n + 2) → C)
(mor : (i : Fin (n + 1)) → obj i.castSucc ⟶ obj i.succ)
(j : Fin (n + 2))
(k : Fin n)
:
obj (j.succAbove k.castSucc) ⟶ obj (j.succAbove k.succ)
Equations
- One or more equations did not get rendered due to their size.
Instances For
theorem
SSet.nerve.δ_mk
{C : Type u}
[inst : CategoryTheory.Category.{v, u} C]
(n : ℕ)
(obj : Fin (n + 2) → C)
(mor : (i : Fin (n + 1)) → obj i.castSucc ⟶ obj i.succ)
(j : Fin (n + 2))
:
CategoryTheory.SimplicialObject.δ (CategoryTheory.nerve C) j (SSet.nerve.mk (n + 1) obj mor) = SSet.nerve.mk n (obj ∘ j.succAbove) (SSet.nerve.δ_mk_mor n obj mor j)
def
SSet.nerve.arrow
{C : Type u}
[inst : CategoryTheory.Category.{v, u} C]
(f : (CategoryTheory.nerve C).obj (Opposite.op (SimplexCategory.mk 1)))
:
f.obj 0 ⟶ f.obj 1
Equations
Instances For
theorem
SSet.nerve.horn_app_obj
{C : Type u}
[inst : CategoryTheory.Category.{v, u} C]
(n : ℕ)
(i : Fin (n + 3))
(σ : SSet.horn (n + 2) i ⟶ CategoryTheory.nerve C)
(m : SimplexCategoryᵒᵖ)
(f : (SSet.horn (n + 2) i).obj m)
(k : Fin ((Opposite.unop m).len + 1))
:
(σ.app m f).obj k = (σ.app (Opposite.op (SimplexCategory.mk 0))
(SSet.horn.const n i ((SSet.asOrderHom ↑f) k) (Opposite.op (SimplexCategory.mk 0)))).obj
0
def
SSet.horn.edge''
{n m : ℕ}
{i : Fin (n + 4)}
(f : (SSet.horn (n + 3) i).obj (Opposite.op (SimplexCategory.mk m)))
(a b : Fin (m + 1))
(h : a ≤ b)
:
(SSet.horn (n + 3) i).obj (Opposite.op (SimplexCategory.mk 1))
Equations
- SSet.horn.edge'' f a b h = SSet.horn.edge₃ (n + 3) i ((SSet.asOrderHom ↑f) a) ((SSet.asOrderHom ↑f) b) ⋯ ⋯
Instances For
def
SSet.horn.edge'
{n m : ℕ}
{i : Fin (n + 4)}
(f : (SSet.horn (n + 3) i).obj (Opposite.op (SimplexCategory.mk m)))
(k : ℕ)
(hk : k + 1 ≤ m)
:
(SSet.horn (n + 3) i).obj (Opposite.op (SimplexCategory.mk 1))
Equations
- SSet.horn.edge' f k hk = SSet.horn.edge'' f ⟨k, ⋯⟩ ⟨k + 1, ⋯⟩ ⋯
Instances For
theorem
SSet.morphism_heq
{C : Type u}
[inst : CategoryTheory.Category.{v, u} C]
{X₁ X₂ Y₁ Y₂ : C}
(f₁ : X₁ ⟶ Y₁)
(f₂ : X₂ ⟶ Y₂)
(hX : X₁ = X₂)
(hY : Y₁ = Y₂)
(H :
f₁ = CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom hX)
(CategoryTheory.CategoryStruct.comp f₂ (CategoryTheory.eqToHom ⋯)))
:
HEq f₁ f₂
theorem
SSet.nerve.arrow_app_congr
{C : Type u}
[inst : CategoryTheory.Category.{v, u} C]
(n : ℕ)
(i : Fin (n + 3))
(σ : SSet.horn (n + 2) i ⟶ CategoryTheory.nerve C)
(f g : (SSet.horn (n + 2) i).obj (Opposite.op (SimplexCategory.mk 1)))
(h : f = g)
:
SSet.nerve.arrow (σ.app (Opposite.op (SimplexCategory.mk 1)) f) = CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom ⋯)
(CategoryTheory.CategoryStruct.comp (SSet.nerve.arrow (σ.app (Opposite.op (SimplexCategory.mk 1)) g))
(CategoryTheory.eqToHom ⋯))
theorem
SSet.nerve.horn_app_map
{C : Type u}
[inst : CategoryTheory.Category.{v, u} C]
(n : ℕ)
(i : Fin (n + 4))
(σ : SSet.horn (n + 3) i ⟶ CategoryTheory.nerve C)
(m : ℕ)
(f : (SSet.horn (n + 3) i).obj (Opposite.op (SimplexCategory.mk m)))
(a b : ℕ)
(hab : a ≤ b)
(hbm : b ≤ m)
:
CategoryTheory.ComposableArrows.map' (σ.app (Opposite.op (SimplexCategory.mk m)) f) a b hab hbm = CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom ⋯)
(CategoryTheory.CategoryStruct.comp
(SSet.nerve.arrow (σ.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.edge'' f ⟨a, ⋯⟩ ⟨b, ⋯⟩ ⋯)))
(CategoryTheory.eqToHom ⋯))
noncomputable def
SSet.filler
{C : Type u}
[CategoryTheory.Category.{v, u} C]
{n : ℕ}
{i : Fin (n + 3)}
(σ₀ : SSet.horn (n + 2) i ⟶ CategoryTheory.nerve C)
(h₀ : 0 < i)
(hₙ : i < Fin.last (n + 2))
:
(CategoryTheory.nerve C).obj (Opposite.op (SimplexCategory.mk (n + 2)))
Equations
- SSet.filler σ₀ h₀ hₙ = SSet.nerve.mk (n + 2) (SSet.filler.obj σ₀) (SSet.filler.mor σ₀ h₀ hₙ)
Instances For
theorem
SSet.filler_spec_zero
{C : Type u}
[CategoryTheory.Category.{v, u} C]
⦃i : Fin 3⦄
(σ₀ : SSet.horn 2 i ⟶ CategoryTheory.nerve C)
(h₀ : 0 < i)
(hₙ : i < Fin.last 2)
(j : Fin 3)
(hj : j ≠ i)
:
CategoryTheory.SimplicialObject.δ (CategoryTheory.nerve C) j (SSet.filler σ₀ h₀ hₙ) = σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.face i j hj)
theorem
SSet.nerve.arrow_app_congr'
{C : Type u}
[CategoryTheory.Category.{v, u} C]
{n : ℕ}
{i : Fin (n + 4)}
(σ : SSet.horn (n + 3) i ⟶ CategoryTheory.nerve C)
{f₁ f₂ f₃ g₁ g₂ g₃ : (SSet.horn (n + 3) i).obj (Opposite.op (SimplexCategory.mk 1))}
{h₁ : f₁ = g₁}
{h₂ : f₂ = g₂}
{h₃ : f₃ = g₃}
{hf₁ : (σ.app (Opposite.op (SimplexCategory.mk 1)) f₁).obj 0 = (σ.app (Opposite.op (SimplexCategory.mk 1)) f₂).obj 0}
{hf₂ : (σ.app (Opposite.op (SimplexCategory.mk 1)) f₂).obj 1 = (σ.app (Opposite.op (SimplexCategory.mk 1)) f₃).obj 0}
{hf₃ : (σ.app (Opposite.op (SimplexCategory.mk 1)) f₃).obj 1 = (σ.app (Opposite.op (SimplexCategory.mk 1)) f₁).obj 1}
{hg₁ : (σ.app (Opposite.op (SimplexCategory.mk 1)) g₁).obj 0 = (σ.app (Opposite.op (SimplexCategory.mk 1)) g₂).obj 0}
{hg₂ : (σ.app (Opposite.op (SimplexCategory.mk 1)) g₂).obj 1 = (σ.app (Opposite.op (SimplexCategory.mk 1)) g₃).obj 0}
{hg₃ : (σ.app (Opposite.op (SimplexCategory.mk 1)) g₃).obj 1 = (σ.app (Opposite.op (SimplexCategory.mk 1)) g₁).obj 1}
(H :
SSet.nerve.arrow (σ.app (Opposite.op (SimplexCategory.mk 1)) f₁) = CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom hf₁)
(CategoryTheory.CategoryStruct.comp (SSet.nerve.arrow (σ.app (Opposite.op (SimplexCategory.mk 1)) f₂))
(CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom hf₂)
(CategoryTheory.CategoryStruct.comp (SSet.nerve.arrow (σ.app (Opposite.op (SimplexCategory.mk 1)) f₃))
(CategoryTheory.eqToHom hf₃)))))
:
SSet.nerve.arrow (σ.app (Opposite.op (SimplexCategory.mk 1)) g₁) = CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom hg₁)
(CategoryTheory.CategoryStruct.comp (SSet.nerve.arrow (σ.app (Opposite.op (SimplexCategory.mk 1)) g₂))
(CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom hg₂)
(CategoryTheory.CategoryStruct.comp (SSet.nerve.arrow (σ.app (Opposite.op (SimplexCategory.mk 1)) g₃))
(CategoryTheory.eqToHom hg₃))))
theorem
SSet.filler_spec_succ_aux
{C : Type u}
[CategoryTheory.Category.{v, u} C]
{n : ℕ}
⦃i : Fin (n + 4)⦄
(σ₀ : SSet.horn (n + 3) i ⟶ CategoryTheory.nerve C)
(h₀ : 0 < i)
(hₙ : i < Fin.last (n + 3))
(j : Fin (n + 4))
(hj : j ≠ i)
(k : ℕ)
(hk : k < n + 2)
(hkj : ¬k + 1 < ↑j)
(hkj' : k + 1 = ↑j)
(h2 : k < n + 2)
(h3 :
(σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.edge' (SSet.horn.face i j hj) k hk)).obj 0 = (σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.primitiveEdge h₀ hₙ ⟨k, h2⟩.castSucc)).obj 0)
(h4 : k.succ < (n + 2).succ)
(h5 :
(σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.primitiveEdge h₀ hₙ ⟨k, h2⟩.castSucc)).obj 1 = (σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.primitiveEdge h₀ hₙ ⟨k, h2⟩.succ)).obj 0)
(h6 :
(σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.primitiveEdge h₀ hₙ ⟨k, h2⟩.succ)).obj 1 = (σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.edge' (SSet.horn.face i j hj) k hk)).obj 1)
:
CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom h3)
(CategoryTheory.CategoryStruct.comp
(CategoryTheory.CategoryStruct.comp
(SSet.nerve.arrow (σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.primitiveEdge h₀ hₙ ⟨k, ⋯⟩)))
(CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom h5)
(SSet.nerve.arrow (σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.primitiveEdge h₀ hₙ ⟨k + 1, h4⟩)))))
(CategoryTheory.eqToHom h6)) = SSet.nerve.arrow (σ₀.app (Opposite.op (SimplexCategory.mk 1)) (SSet.horn.edge' (SSet.horn.face i j hj) k hk))
theorem
SSet.filler_spec_succ
{C : Type u}
[CategoryTheory.Category.{v, u} C]
{n : ℕ}
⦃i : Fin (n + 4)⦄
(σ₀ : SSet.horn (n + 3) i ⟶ CategoryTheory.nerve C)
(h₀ : 0 < i)
(hₙ : i < Fin.last (n + 3))
(j : Fin (n + 4))
(hj : j ≠ i)
:
CategoryTheory.SimplicialObject.δ (CategoryTheory.nerve C) j (SSet.filler σ₀ h₀ hₙ) = σ₀.app (Opposite.op (SimplexCategory.mk (n + 2))) (SSet.horn.face i j hj)
instance
SSet.instQuasicategoryNerve_infinityCosmos
(C : Type u)
[CategoryTheory.Category.{v, u} C]
:
(CategoryTheory.nerve C).Quasicategory
The nerve of a category is a quasicategory.
[Kerodon, 0032]
Equations
- ⋯ = ⋯