The Augmented simplex category #
This file defines the AugmentedSimplexCategory
as the category obtained by adding an initial
object to SimplexCategory
(using CategoryTheory.WithInitial
).
This definition provides a canonical full and faithful inclusion functor
inclusion : SimplexCategory ⥤ AugmentedSimplexCategory
.
We prove that functors out of AugmentedSimplexCategory
are equivalent to augmented cosimplicial
objects and that functors out of AugmentedSimplexCategoryᵒᵖ
are equivalent to augmented simplicial
objects, and we provide a translation of the main constrcutions on augmented (co)simplicial objects
(i.e drop
, point
and toArrow
) in terms of these equivalences.
TODOs #
- Define a monoidal structure on
AugmentedSimplexCategory
.
The AugmentedSimplexCategory
is the category obtained from SimplexCategory
by adjoining an
initial object.
Instances For
The canonical inclusion from SimplexCategory
to AugmentedSimplexCategory
.
Instances For
The equivalence between functors out of AugmentedSimplexCategory
and augmented
cosimplicial objects.
Equations
Instances For
Through the equivalence (AugmentedSimplexCategory ⥤ C) ≌ CosimplicialObject.Augmented C
,
dropping the augmentation corresponds to precomposition with
inclusion : SimplexCategory ⥤ AugmentedSimplexCategory
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Through the equivalence (AugmentedSimplexCategory ⥤ C) ≌ CosimplicialObject.Augmented C
,
taking the point of the augmentation corresponds to evaluation at the initial object.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Through the equivalence (AugmentedSimplexCategory ⥤ C) ≌ CosimplicialObject.Augmented C
,
the arrow attached to the cosimplicial object is the one obtained by evaluation at the unique arrow
star ⟶ of [0]
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The equivalence between functors out of AugmentedSimplexCategory
and augmented simplicial
objects.
Equations
Instances For
Through the equivalence (AugmentedSimplexCategoryᵒᵖ ⥤ C) ≌ SimplicialObject.Augmented C
,
dropping the augmentation corresponds to precomposition with
inclusionᵒᵖ : SimplexCategoryᵒᵖ ⥤ AugmentedSimplexCategoryᵒᵖ
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Through the equivalence (AugmentedSimplexCategory ⥤ C) ≌ CosimplicialObject.Augmented C
,
taking the point of the augmentation corresponds to evaluation at the initial object.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Through the equivalence (AugmentedSimplexCategory ⥤ C) ≌ CosimplicialObject.Augmented C
,
the arrow attached to the cosimplicial object is the one obtained by evaluation at the unique arrow
star ⟶ of [0]
.
Equations
- One or more equations did not get rendered due to their size.