title: Do empty model group definitions in XSD change the defined valid XML language?
body: <p>In <a href="https://www.autosar.org/fileadmin/user_upload/standards/adaptive/19-11/AUTOSAR_MMOD_XMLSchema.zip" rel="nofollow noreferrer">AUTOSAR_00048.xsd</a> there are many model group definitions with a sequence with no particles, like this:</p>
  <pre><code>&lt;xsd:group xmlns:xsd=&quot;http://www.w3.org/2001/XMLSchema&quot; xmlns:AR=&quot;http://autosar.org/schema/r4.0&quot; name=&quot;AR-ELEMENT&quot;&gt;
    &lt;xsd:sequence/&gt;
  &lt;/xsd:group&gt;
  </code></pre>
  <p>I don't know if a model group can be extended in some way. But there is definitely no extension of <code>AR-ELEMENT</code> in this XSD.</p>
  <p>My question is whether such a &quot;empty&quot; group model changes the sets of XML instances specified by the XSD. Or whether such model group definitions could also be missing and the language determined by the XSD would still be the same.</p>