lowing
criteria:</p>

<ol>
<li>
<p>It must validate against one of the three DTDs found in <a
href="#dtds">Appendix&#160;A</a>.</p>
</li>

<li>
<p>The root element of the document must be <code>
&lt;html&gt;</code>.</p>
</li>

<li>
<p>The root element of the document must designate the XHTML
namespace using the <code>xmlns</code> attribute <a href= 
"#ref-xmlns">[XMLNAMES]</a>. The namespace for XHTML is
defined to be 
<code>http://www.w3.org/1999/xhtml</code>.</p>
</li>

<li>
<p>There must be a DOCTYPE dec