The following proposal for additions to SKOS Core to support subject-based
indexing has been actioned:
Add the following properties to SKOS Core:
- subject
- isSubjectOf
- primarySubject
- isPrimarySubjectOf
Additionally, the following points are a part of this proposal:
(1) skos:subject is a sub-property of dc:subject.
(2) skos:subject and skos:isSubjectOf are inverse.
(3) skos:primarySubject is a sub-property of skos:subject.
(4) skos:primarySubject and skos:isPrimarySubjectOf are inverse.
(5) Wrt skos:subject, the following rule applies:
(?d skos:subject ?x)(?x skos:broader ?y) -> (?d skos:subject ?y)
See the SKOS Core Vocabulary Specification for an overview of these terms:
http://www.w3.org/2004/02/skos/core/spec/
All new terms have an 'unstable' status and comments and suggestions are
most welcome.
The following properties have been added to SKOS Core:
- publicNote
- privateNote
- historyNote
- editorialNote
- changeNote
In addition, the following properties have been modified:
- definition
- example
- scopeNote
The modifications were:
(i) rdfs:domain statements removed.
(ii) Super-property statements changed.
Definitions, comments and usage examples for these properties can be viewed
via the SKOS Core Vocabulary Specification at:
http://www.w3.org/2004/02/skos/core/spec/
N.B. all new note properties have an unstable status, and
comments/suggestions are welcomed.
These 8 properties constitute the set of SKOS Core note properties. They
are arranged into a property hierarchy as follow:
rdfs:comment
skos:publicNote
skos:definition
skos:example
skos:scopeNote
skos:historyNote
skos:privateNote
skos:editorialNote
skos:changeNote
N.B. None of these properties have any rdfs domain/range statements, and so
may be used to describe resources of any type.
Some new vocabulary has been added to SKOS Core to support ordered/labelled collections of concepts. The primary use case for these terms is creating RDF descriptions of thesauri that have 'guide terms' and/or 'node labels'.
See the SKOS Core Vocabulary Specification for an overview of the new terms.
All new terms have an 'unstable' status, so further comments and suggestions are most welcome.
Description of the actioned proposal:
Add the following classes:
- Collection
- OrderedCollection (sub-class of Collection)
- CollectableProperty
Add the following properties:
- member (domain: Collection, range: rdf:Resource)
- memberList (domain: Collection, range: rdf:List)
To illustrate the intended usage by example, an *unordered* labelled
collection would be represented in RDF/XML as:
<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/concept#102">
<skos:prefLabel>Aircraft</skos:prefLabel>
<skos:narrower>
<skos:Collection>
<rdfs:label>Aircraft by function</rdfs:label>
<skos:member rdf:resource="http://my.example.org/concept#1024"/>
<skos:member rdf:resource="http://my.example.org/concept#1026"/>
<skos:member rdf:resource="http://my.example.org/concept#1027"/>
<skos:member rdf:resource="http://my.example.org/concept#1028"/>
<skos:member rdf:resource="http://my.example.org/concept#1029"/>
</skos:Collection>
</skos:narrower>
</skos:Concept>
</rdf:RDF>
An *ordered*, labelled collection would be represented in RDF/XML as:
<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/concept#56">
<skos:prefLabel>Countries</skos:prefLabel>
<skos:narrower>
<skos:OrderedCollection>
<rdfs:label>Countries by size</rdfs:label>
<skos:memberList rdf:parseType="Collection">
<skos:Concept rdf:about="http://my.example.org/concept#564"/>
<skos:Concept rdf:about="http://my.example.org/concept#565"/>
<skos:Concept rdf:about="http://my.example.org/concept#566"/>
<skos:Concept rdf:about="http://my.example.org/concept#568"/>
<skos:Concept rdf:about="http://my.example.org/concept#560"/>
<skos:Concept rdf:about="http://my.example.org/concept#562"/>
</skos:memberList>
</skos:OrderedCollection>
</skos:narrower>
</skos:Concept>
</rdf:RDF>
The following points are also part of this proposal:
(1) Collections may be nested as members of other collections.
(2) Wrt 'CollectableProperty' the following rule applies:
(?p rdf:type skos:CollectableProperty) (?x ?p ?c) (?c skos:member ?m) -> (?x ?p ?m)
(3) skos:narrower is declared to be of type skos:CollectableProperty
(4) Wrt 'memberList' the following dependency rule applies:
(?c skos:memberList ?l) elementOfList(?e,?l) -> (?c skos:member ?e)
For all the current terms of the SKOS Core vocabulary, a skos:definition
property has been added, and a skos:example property has been added. The
values for the rdfs:comment properties have also been updated.
This structure is employed such that the formal definition of a term is
described by the skos:definition property, and any additional comments and
information about the term are described by rdfs:comment property(ies).
The skos:example properties point to RDF/XML files containing examples of
usage.
No SKOS Core terms are yet assigned a 'stable' status, which means that
comments and feedback on any current definitions and comments is most
welcome.
To view comments and definitions in a more user-friendly form, see the SKOS
Core Vocabulary Specification, which is generated directly from the
underlying RDF description:
http://www.w3.org/2004/02/skos/core/spec/
The following SKOS Core properties have been deprecated [where the prefix
'skos' stands for 'http://www.w3.org/2004/02/skos/core#']:
skos:broaderInstantive
skos:broaderGeneric
skos:broaderPartitive
skos:narrowerInstantive
skos:narrowerGeneric
skos:narrowerPartitive
skos:relatedhasPart
skos:relatedIsPartOf
These properties are replaced by properties in the SKOS Extensions
Vocabulary namespace with the same names.
The base namespace for the SKOS Extensions vocabulary is:
http://www.w3.org/2004/02/skos/extensions#
The SKOS Extensions Vocabulary homepage is at:
http://www.w3.org/2004/02/skos/extensions/
The RDF description of the SKOS Extensions Vocabulary is at:
http://www.w3.org/2004/02/skos/extensions.rdf
The SKOS Extensions Vocabulary Specification is at:
http://www.w3.org/2004/02/skos/extensions/spec/