tation "AXIOM: Abstract is a class.")
&gt; &gt;
&gt; &gt; (Class Abstract)
&gt; &gt;
&gt; &gt; (documentation "AXIOM: ?x is abstract iff it has neither a spatial nor 
&gt; temporal location.")
&gt; &gt;
&gt; &gt; ;; NOTE: "located-at" and "exists-at" are spatial and temporal
&gt; &gt; ;; predicates, respectively, that are not axiomatized here.
&gt; &gt; ;; "exists-at" is defined in the PSL temporal ontology, which
&gt; &gt; ;; axiomatizes "timepoint".  This relation holds between an entity and
&gt; &gt; ;; 