<grammar xmlns="http://relaxng.org/ns/structure/1.0">
  <include href="included.rng">
    <define name="included.start.element">
      <ref name="s<caret>" />
    </define>
  </include>

  <start>
    <ref name="start.element" />
  </start>

  <div>
    <define name="start.element" />
  </div>
</grammar>