ction.html" title="Incomplete Beta Functions">ibetac</a>
          require <span class="emphasis"><em>a,b &gt;= 0</em></span>, and in addition that not both
          <span class="emphasis"><em>a</em></span> and <span class="emphasis"><em>b</em></span> are zero.
        </p>
<p>
          The functions <a class="link" href="beta_function.html" title="Beta">beta</a>
          and <a class="link" href="ibeta_function.html" title="Incomplete Beta Functions">betac</a>
          require <span class="emphasis"><e