<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/xhtml-math11-f.dtd" >

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

</head>

<body>

<p>
  <math xmlns="http://www.w3.org/1998/Math/MathML">
    <msub>
      <mi>x</mi>
      <mn>2</mn>
    </msub>
  </math>
</p>

</body>

</html>