 Namespaces and inclusion
&gt;
&gt; An ontology (traditionally called a 'theory' in logic) is a set of
&gt; assertional expressions. Each ontology has an associated vocabulary
&gt; or namespace, defined to be all the identifiers used in its
&gt; expressions, other than those with a predefined logical meaning.  A
&gt; KIF ontology can be given a name, which can be indicated in KIF  by
&gt; enclosing all the expressions of the ontology, preceded by the word
&gt; "ontology" and the name itself, within parenthe