DAML+OIL for Application Developers - slide "Statement IDs"

we can use a statement as the subject of another statement
- this is useful for recording source, timetamp, uncertainty, etc.

we give a statement an ID by specifying rdf:ID with the predicate, e.g.


  <Person rdf:ID="jhd">
    <born rdf:ID="stmt1">1923-10-23</born>
    <died rdf:ID="stmt2">1999-03-17</died>
  </Person>
  <rdf:Description rdf:about="#stmt1">
    <source rdf:resource="http://..."/>
  </rdf:Description>
  <rdf:Description rdf:about="#stmt2">
    <source rdf:resource="http://www.detnews.com/obituaries/..."/>
  </rdf:Description>

statement IDs are part of an RDF feature called reification