Subject-Based Indexing with SKOS Concepts

To declare that a concept is the 'subject' of a document, do for example:

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns:skos="http://www.w3.org/2004/02/skos/core#">

  <rdf:Description rdf:about="http://my.example.org/aDocument.html">
    <skos:subject rdf:resource="http://my.example.org/GCL/462#concept"/>
  </rdf:Description>

</rdf:RDF>

The skos:subject property is a sub-property of dc:subject, and carries the same meaning.

Alternatively, you can state for example:

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns:skos="http://www.w3.org/2004/02/skos/core#">

  <rdf:Description rdf:about="http://my.example.org/GCL/462#concept">
    <skos:isSubjectOf rdf:resource="http://my.example.org/aDocument.html"/>
  </rdf:Description>

</rdf:RDF>

The skos:subject and skos:isSubjectOf properties are each other's inverse.

A document may have any number of subjects. To express the fact that some concept is the primary subject of a document, do for example:

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns:skos="http://www.w3.org/2004/02/skos/core#">

  <rdf:Description rdf:about="http://my.example.org/aDocument.html">
    <skos:primarySubject rdf:resource="http://my.example.org/GCL/701#concept"/>
  </rdf:Description>

</rdf:RDF>

A document should have only one skos:primarySubject property per concept scheme.

The property skos:isPrimarySubjectOf is the inverse of skos:primarySubject.

Additionally, the following rule applies to skos:subject:

(?document skos:subject ?y) (?y skos:broader ?z)
->
(?document skos:subject ?z)

End section