Simplicial objects in a category. #
A simplicial object in a category C is a C-valued presheaf on SimplexCategory.
(Similarly, a cosimplicial object is a functor SimplexCategory ⥤ C.)
Notation #
The following notations can be enabled via open Simplicial.
X _⦋n⦌denotes then-th term of a simplicial objectX, wheren : ℕ.X ^⦋n⦌denotes then-th term of a cosimplicial objectX, wheren : ℕ.
The following notations can be enabled via
open CategoryTheory.SimplicialObject.Truncated.
X _⦋m⦌ₙdenotes them-th term of ann-truncated simplicial objectX.X ^⦋m⦌ₙdenotes them-th term of ann-truncated cosimplicial objectX.
The category of simplicial objects valued in a category C.
This is the category of contravariant functors from SimplexCategory to C.
Pretty printer defined by notation3 command.
Equations
- One or more equations did not get rendered due to their size.
X _⦋n⦌ denotes the nth-term of the simplicial object X
Equations
- One or more equations did not get rendered due to their size.
Face maps for a simplicial object.
Equations
- X.δ i = X.map (SimplexCategory.δ i).op
Degeneracy maps for a simplicial object.
Equations
- X.σ i = X.map (SimplexCategory.σ i).op
The diagonal of a simplex is the long edge of the simplex.
Equations
- X.diagonal = X.map (SimplexCategory.diag n).op
Isomorphisms from identities in ℕ.
Equations
The generic case of the first simplicial identity
The special case of the first simplicial identity
The second simplicial identity
The first part of the third simplicial identity
The second part of the third simplicial identity
The fourth simplicial identity
The fifth simplicial identity
Functor composition induces a functor on simplicial objects.
Truncated simplicial objects.
Functor composition induces a functor on truncated simplicial objects.
For X : Truncated C n and m ≤ n, X _⦋m⦌ₙ is the m-th term of X. The
proof p : m ≤ n can also be provided using the syntax X _⦋m, p⦌ₙ.
Equations
- One or more equations did not get rendered due to their size.
Further truncation of truncated simplicial objects.
Equations
- One or more equations did not get rendered due to their size.
The truncation functor from simplicial objects to truncated simplicial objects.
For all m ≤ n, truncation m factors through Truncated n.
The n-skeleton as a functor SimplicialObject.Truncated C n ⥤ SimplicialObject C.
The n-coskeleton as a functor SimplicialObject.Truncated C n ⥤ SimplicialObject C.
The n-skeleton as an endofunctor on SimplicialObject C.
The n-coskeleton as an endofunctor on SimplicialObject C.
The adjunction between the n-skeleton and n-truncation.
The adjunction between n-truncation and the n-coskeleton.
Since Truncated.inclusion is fully faithful, so is right Kan extension along it.
Equations
- One or more equations did not get rendered due to their size.
Since Truncated.inclusion is fully faithful, so is left Kan extension along it.
Equations
- One or more equations did not get rendered due to their size.
The constant simplicial object is the constant functor.
The category of augmented simplicial objects, defined as a comma category.
Drop the augmentation.
The point of the augmentation.
The functor from augmented objects to arrows.
Equations
- One or more equations did not get rendered due to their size.
The compatibility of a morphism with the augmentation, on 0-simplices
Functor composition induces a functor on augmented simplicial objects.
Equations
- One or more equations did not get rendered due to their size.
Functor composition induces a functor on augmented simplicial objects.
Equations
- One or more equations did not get rendered due to their size.
The constant augmented simplicial object functor.
Equations
- One or more equations did not get rendered due to their size.
Augment a simplicial object with an object.
Equations
- One or more equations did not get rendered due to their size.
Cosimplicial objects.
X ^⦋n⦌ denotes the nth-term of the cosimplicial object X
Equations
- One or more equations did not get rendered due to their size.
Pretty printer defined by notation3 command.
Equations
- One or more equations did not get rendered due to their size.
Coface maps for a cosimplicial object.
Equations
- X.δ i = X.map (SimplexCategory.δ i)
Codegeneracy maps for a cosimplicial object.
Equations
- X.σ i = X.map (SimplexCategory.σ i)
Isomorphisms from identities in ℕ.
Equations
The generic case of the first cosimplicial identity
The special case of the first cosimplicial identity
The second cosimplicial identity
The first part of the third cosimplicial identity
The second part of the third cosimplicial identity
The fourth cosimplicial identity
The fifth cosimplicial identity
Functor composition induces a functor on cosimplicial objects.
Truncated cosimplicial objects.
Functor composition induces a functor on truncated cosimplicial objects.
For X : Truncated C n and m ≤ n, X ^⦋m⦌ₙ is the m-th term of X. The
proof p : m ≤ n can also be provided using the syntax X ^⦋m, p⦌ₙ.
Equations
- One or more equations did not get rendered due to their size.
Further truncation of truncated cosimplicial objects.
Equations
- One or more equations did not get rendered due to their size.
The truncation functor from cosimplicial objects to truncated cosimplicial objects.
For all m ≤ n, truncation m factors through Truncated n.
Equations
- One or more equations did not get rendered due to their size.
The constant cosimplicial object.
Augmented cosimplicial objects.
Drop the augmentation.
The point of the augmentation.
The functor from augmented objects to arrows.
Equations
- One or more equations did not get rendered due to their size.
Functor composition induces a functor on augmented cosimplicial objects.
Equations
- One or more equations did not get rendered due to their size.
Functor composition induces a functor on augmented cosimplicial objects.
Equations
- One or more equations did not get rendered due to their size.
The constant augmented cosimplicial object functor.
Equations
- One or more equations did not get rendered due to their size.
Augment a cosimplicial object with an object.
Equations
- One or more equations did not get rendered due to their size.
The anti-equivalence between simplicial objects and cosimplicial objects.
The anti-equivalence between cosimplicial objects and simplicial objects.
Construct an augmented cosimplicial object in the opposite category from an augmented simplicial object.
Equations
- X.rightOp = { left := Opposite.op X.right, right := CategoryTheory.Functor.rightOp X.left, hom := CategoryTheory.NatTrans.rightOp X.hom }
Construct an augmented simplicial object from an augmented cosimplicial object in the opposite category.
Equations
- X.leftOp = { left := CategoryTheory.Functor.leftOp X.right, right := Opposite.unop X.left, hom := CategoryTheory.NatTrans.leftOp X.hom }
Converting an augmented simplicial object to an augmented cosimplicial object and back is isomorphic to the given object.
Converting an augmented cosimplicial object to an augmented simplicial object and back is isomorphic to the given object.
A functorial version of SimplicialObject.Augmented.rightOp.
Equations
- One or more equations did not get rendered due to their size.
A functorial version of Cosimplicial_object.Augmented.leftOp.
Equations
- One or more equations did not get rendered due to their size.
The contravariant categorical equivalence between augmented simplicial objects and augmented cosimplicial objects in the opposite category.
Equations
- One or more equations did not get rendered due to their size.