category theory

homotopy theory

# Contents

## Definition

The category $sSet_+$ of augmented simplicial sets is the category of presheaves on the augmented version of the simplex category $\Delta_a$:

$sSet_+ := Set^{\Delta^{op}_a} \,.$

This is the category whose objects are augmented simplicial sets and whose morphisms are the evident morphisms between these.

## Applications

The join of simplicial sets is most naturally defined via a construction on augmented simplicial sets.

category: category

Revised on November 4, 2010 08:48:44 by Urs Schreiber (87.212.203.135)