ates and Fluents of objects</li>
  <li>to allow processes to reference / test and update fluents in a
time dependant way.</li>
</ul>
<h3>OclPlus in the History Editor</h3>
This description assumes that the reader is already familiar with the
basic operation of the History Editor.
<h4>Numeric Properties</h4>
<b>Fluents</b> are properties of objects and can be defined relative
any state node for an object sort.
Right clicking on a selected state node will give in addition to the
normal options the option <b>F