Namespace Example

<doc xmlns:m="http://www.w3.org/1998/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">
<title>My Document</title>
<body xmlns='http://www.w3.org/1999/xhtml">
<p xlink:href="alternate.xml">I am a paragraph containing some mathematics: 
<m:math><m:mi>x</m:mi></m:math>
</p>
</body>
</doc>

The 'doc' element--the document element--has no namespace.
The 'title' element has no namespace.
The 'body' element defaults the XHTML namespace.
The 'p' element is in the default XHTML namespace.
The 'href' attribute is in the namespace associated with the 'xlink' prefix declared on the 'doc' element.
The 'math' element is in the namespace associated with the 'm' prefix declared on the 'doc' element.