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 constructions on augmented (co)simplicial objects
(i.e drop, point and toArrow) in terms of these equivalences.
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.
Instances For
Through the equivalence (AugmentedSimplexCategory ⥤ C) ≌ CosimplicialObject.Augmented C,
dropping the augmentation corresponds to precomposition with
inclusion : SimplexCategory ⥤ AugmentedSimplexCategory.
Instances For
Through the equivalence (AugmentedSimplexCategory ⥤ C) ≌ CosimplicialObject.Augmented C,
taking the point of the augmentation corresponds to evaluation at the initial object.
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].
Instances For
The equivalence between functors out of AugmentedSimplexCategory and augmented simplicial
objects.
Instances For
Through the equivalence (AugmentedSimplexCategoryᵒᵖ ⥤ C) ≌ SimplicialObject.Augmented C,
dropping the augmentation corresponds to precomposition with
inclusionᵒᵖ : SimplexCategoryᵒᵖ ⥤ AugmentedSimplexCategoryᵒᵖ.
Instances For
Through the equivalence (AugmentedSimplexCategory ⥤ C) ≌ CosimplicialObject.Augmented C,
taking the point of the augmentation corresponds to evaluation at the initial object.
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].