<?xml version=“1.0”?> <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Strict//EN” “www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd”> <html xmlns=“www.w3.org/1999/xhtml”>

<body>
  <h1><abbr>a</abbr> b</h1>
</body>

</html>