Namespaces
Variants
Actions

Pointed object

From Encyclopedia of Mathematics
Revision as of 21:56, 2 November 2014 by Richard Pinch (talk | contribs) (better)
Jump to: navigation, search

of a category having a terminal object

A pair (X,x_0) where X \in \mathrm{Ob}\,\mathcal{C} and x_0 is a morphism of the terminal object into X. An example is a pointed topological space (see Pointed space). The pointed objects of \mathcal{C} form a category, in which the morphisms are the mappings sending the distinguished point to the distinguished point.


Comments

The category of pointed objects of \mathcal{C} has a zero object (see Null object of a category), namely the terminal object of \mathcal{C} equipped with its unique point. Conversely, if a category \mathcal{C} has a zero object, then it is isomorphic to its own category of pointed objects.

How to Cite This Entry:
Pointed object. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Pointed_object&oldid=34260
This article was adapted from an original article by A.F. Kharshiladze (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article