3.1 Derivation Chain

<emma:emma version="1.0" xmlns:emma="http://www.w3.org/2003/04/emma">
  <emma:interpretation id="raw">
    <answer>From Boston to Denver tomorrow</answer>
  </emma:interpretation>

  <emma:interpretation id="better">
    <emma:derived-from resource="#raw" />
    <origin>Boston</origin>
    <destination>Denver</destination>
    <date>tomorrow</date>
  </emma:interpretation>

  <emma:interpretation id="best">
    <emma:derived-from resource="#better" />
    <origin>Boston</origin>
    <destination>Denver</destination>
    <date>20030315</date>
  </emma:interpretation>
</emma:emma>