ass is also a member
of a subordinate class that restricts the values of its properties.
(<span class="defn">change-class</span> can then be used to change the instance&rsquo;s
class to the subordinate class.)</p>

<p class="bodytext">Its use presumes that subordinate classes are disjoint
(see <span class="section"><a href="reasoner.html#section7a.1">Compound
Objects</a></span>), and that <em>either</em> they have been fully enumerated and are
differentiated by varying restrictions of the same property or p