There are 2 ways of doing MathML with XHTML:

  <ul>
    <li> Use the "-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN" DTD. This makes it easier for your XML editor. It is also useful to define the mathml namespace as na entity (Make typing shorter for each "math" fragment). See file
      <a href="xhtml-plus-mathml-test.xml">xhtml-plus-mathml-test.xml</a>. Important: le fichier doit etre servi come *.xml !! (ou à TECFA comme *.xhtml, ce qui revient au même) </li>

    
    <li> Use MathML by just declaring the namespace: 
      See file <a href="xhtml-with-mathml-test.xhtml">xhtml-with-mathml-test.xhtml</a>.
 </li>

    
    <li> Tested with Mozilla 1.2 </li>

  </ul>