PhySH - Physics Subject Headings

PhySH is provided in RDF largely using the entities and relationships defined by SKOS. We have added to the RDF vocabulary using a custom ontology with canonical URI https://physh.org/rdf/2018/01/01/core# (prefix "physh_rdf" in what follows) - this defines the following classes:

• physh_rdf:Discipline as type for disciplines; these are also of type skos:ConceptScheme
• physh_rdf:Facet as type for facets; these are also of type skos:Concept
• physh_rdf:Concept skos:Concept's that are not facets.

and the following properties:

• physh_rdf:contains - facet contains this concept
• physh_rdf:deprecated - concept should no longer be used
• physh_rdf:excludeFromIndexing - concept should not be returned as a search result
• physh_rdf:hasConcept - discipline has this concept
• physh_rdf:inDiscipline - concept is in a particular discipline
• physh_rdf:inFacet - concept is in a particular facet
• physh_rdf:prefLabel - like skos:prefLabel, but applies to concept schemes also
• physh_rdf:usedByDiscipline - facet is used by this discipline
• physh_rdf:usesFacet - discipline uses this facet

Note that contains and inFacet are inverses, as are hasConcept and inDiscipline, and usedByDiscipline and usesFacet; the PhySH RDF files include both sides of these relations. We also use the Dublin core terms vocabulary (http://purl.org/dc/terms/ - dcterms) to provide metadata for the concept schemes/disciplines.