Concept Hierarchies and Relationships

This section describes how to declare relationships between concepts.

See also the section [custom semantic relation properties].

Hierarchies

To describe the fact that one concept is 'broader' in sense than another (i.e. is more general in scope), do for example (adapted from GCL [ref]):

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

   <skos:Concept rdf:about="http://my.example.org/GCL/462#concept">
      <skos:prefLabel>Tourism</skos:prefLabel>
      <skos:broader rdf:resource="http://my.example.org/GCL/616#concept"/>
      <skos:broader rdf:resource="http://my.example.org/GCL/705#concept"/>
   </skos:Concept>

   <skos:Concept rdf:about="http://my.example.org/GCL/616#concept">
      <skos:prefLabel>Arts, recreation and travel</skos:prefLabel>
   </skos:Concept>

   <skos:Concept rdf:about="http://my.example.org/GCL/705#concept">
      <skos:prefLabel>Distribution and service industries</skos:prefLabel>
   </skos:Concept>

</rdf:RDF>

To describe the fact that one concept is 'narrower' in sense than another (i.e. is more specific in scope), do for example (adapted from PACS [ref]):

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

  <skos:Concept rdf:about="http://my.example.org/PACS/40.#concept">
    <skos:prefLabel>ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS</skos:prefLabel>
    <skos:narrower rdf:resource="http://my.example.org/scheme/concept/PACS41."/>
  </skos:Concept>

  <skos:Concept rdf:about="http://my.example.org/PACS/41.#concept">
    <skos:prefLabel>Electromagnetism; electron and ion optics</skos:prefLabel>
    <skos:narrower rdf:resource="http://my.example.org/PACS/41.50.+h#concept"/>
  </skos:Concept>

  <skos:Concept rdf:about="http://my.example.org/PACS/41.50.+h#concept">
    <skos:prefLabel>X-ray beams and x-ray optics</skos:prefLabel>
  </skos:Concept>

</rdf:RDF>

Note that skos:narrower and skos:broader should be implementated as each other's inverse.

Associative Relationships

To describe the fact that one concept is 'related' in sense to another, do for example (adapted from AAT [ref]):

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

  <skos:Concept rdf:about="http://my.example.org/AAT/300185689#concept">
    <skos:prefLabel xml:lang="en">armed conflicts</skos:prefLabel>
    <skos:related rdf:resource="http://my.example.org/AAT/300230820#concept"/>
    <skos:related rdf:resource="http://my.example.org/AAT/300055312#concept"/>
  </skos:Concept>          

  <skos:Concept rdf:about="http://my.example.org/AAT/300230820#concept">
    <skos:prefLabel xml:lang="en">jousts</skos:prefLabel>
    <skos:related rdf:resource="http://my.example.org/AAT/300185689#concept"/>
  </skos:Concept>          

  <skos:Concept rdf:about="http://my.example.org/AAT/300055312#concept">
    <skos:prefLabel xml:lang="en">revolutions</skos:prefLabel>
    <skos:related rdf:resource="http://my.example.org/AAT/300185689#concept"/>
  </skos:Concept>

</rdf:RDF>

Note that skos:related should be implementated as a symmetric property.

End section