XHTML with Other Vocabularies

  <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
      <title>A Math Example</title>
    </head>
    <body>
      <p>The following is MathML markup:</p>
        <math xmlns="http://www.w3.org/1998/Math/MathML">
          <apply> <log/>
            <logbase>
              <cn> 3 </cn>
            </logbase>
            <ci> x </ci>
          </apply>
        </math>
    </body>
  </html>