title: how do schema validators know where to find the xsd associated with the namespace in xmlns?
body: <p>I'm calling an external (3rd party) web service which is returning xml containing namespaces like such:</p>
  
  <pre><code>...
    xmlns:gml="http://www.opengis.net/gml"
    xmlns:wrs="http://www.opengis.net/cat/wrs/1.0"
    xmlns:rim="urn:oasis:names:tc:ebxml-regrep:xsd:rim:3.0"
  ...
  </code></pre>
  
  <p>I'm interested in the last namespace that starts with <strong>urn:oasis</strong>.</p>
  
  <p>how do validators know how to validate the file if there is no location specified?</p>
  
  <p>I know the first ones don't have location specified either as they are just a namespace. </p>
  
  <p>Could you elaborate on the following statement made in <a href="http://www.ibm.com/developerworks/xml/library/x-namcar/index.html" rel="nofollow">this article</a>:</p>
  
  <blockquote>
    <p><strong>use URNs if your organization has a means of managing and resolving a suitable class of URN</strong></p>
  </blockquote>
  
  <p><strong>How do these validators work without locations?</strong></p>