ralized posynomials;</li>
<li>the product of two or more generalized posynomials;</li>
<li>the ratio of a generalized posynomial and a monomial;</li>
<li>a generalized posynomial raised to a positive real power; or</li>
<li>a call to one of the following functions with arguments that are
generalized posynomials: <tt class="docutils literal"><span class="pre">sum</span></tt>, <tt class="docutils literal"><span class="pre">cumsum</span></tt>, <tt class="docutils literal"><span class="pre">mean</span></tt>, <t