nbsp;&nbsp;&nbsp;&nbsp;</th>
          <td>Union</td>
          <td><tt>[a-e][i-u]<tt></td></tr>
      <tr><th>5&nbsp;&nbsp;&nbsp;&nbsp;</th>

          <td>Intersection</td>
          <td><tt>[a-z&&[aeiou]]</tt></td></tr>
    </table></blockquote>

    <p> Note that a different set of metacharacters are in effect inside
    a character class than outside a character class. For instance, the
    regular expression <tt>.</tt> loses its special meaning inside a
    character class, while the expression <tt>-<