Classes
==============
**Classes** are collections of **individuals**.  A university, a nonprofit, building, 
and a role in a project are
all individuals.  Classes of individuals are defined by specifying members 
(extension) or more frequently 
in scholarship, by specifying conditions (intension).

In ontologies, and using :ref:`OWL <glossary>`, individuals
instances of classes. Classes are arranged
in subsumption hierarchies, indicating that individuals in one class are members of some 
higher class.  For example, a cat is a mammal.  Your cat is an instance of the
class cat.  All cats are mammals.  We say cat is a subclass of mammal.  We can infer 
that all individuals that are
cats are mammals.  Your cat is a cat, so we can infer your cat is a mammal.


All Classes
-----------------

.. include:: tab-all-classes.txt

.. include:: toc-Class.txt


.. We have have a script that can read the ontology and write documentation pages, one per
   class.  The class pages will be listed in a toctree directive generated by the script 
   and included here.  In this way, we make sure all the classes are documented and that
   the document for each is generated automatically from the ontology.