SKOS and metadata

MatSci-SAM uses SKOS for concepts and relations, Dublin Core for attribution and subject, OWL for deprecation, and PROV-O for history. Application-specific classes and properties use {identifier-base}/metadata#.

Documents

Metadata access lists the downloads and named graphs. /vocabulary.ttl includes the vocabulary and classification records. /tags.ttl includes tag schemes, concepts, and collections. Per-term documents include the owning vocabulary and referenced tags and schemes.

Readable /skos.ttl and /skos.jsonld paths describe the same RDF graph. The JSON-LD form is an expanded array of nodes. Legacy numeric JSON-LD endpoints retain their earlier representation. Provenance is available separately from current vocabulary content.

Classes and properties

Resource	Class	Principal properties
Vocabulary	`skos:ConceptScheme`	`dcterms:title`, `dcterms:description`, `dcterms:publisher`
Term	`skos:Concept`	`skos:inScheme`, `skos:prefLabel`, `skos:definition`, `matsci:canonicalDefinition`
Tag scheme	`skos:ConceptScheme`	`dcterms:title`, `dcterms:description`, `skos:hasTopConcept`
Tag	`skos:Concept`	`skos:inScheme`, `skos:prefLabel`, `skos:altLabel`, `skos:definition`, `skos:scopeNote`
Collection	`skos:Collection`	`skos:prefLabel`, `dcterms:description`, `skos:member`
Definition	`matsci:Definition`	`dcterms:isPartOf`, `matsci:definitionNumber`, `matsci:currentRevision`, `dcterms:hasVersion`
Revision	`matsci:DefinitionRevision`	`rdf:value`, `skos:example`, `dcterms:isVersionOf`, `prov:specializationOf`, `matsci:version`, `matsci:status`

Term records also publish contributors and creation dates. Definitions and revisions retain creation dates, and revisions list creators. Terms and definitions use dcterms:subject for classification.

Conventions

A term belongs to the default /vocabulary scheme or a community scheme at /vocabulary/{community}. Same-label terms in different schemes retain separate IRIs and definitions.

skos:definition links a term to each current definition revision. matsci:canonicalDefinition identifies the highest-ranked stable candidate, and matsci:currentRevision identifies its current wording. The ordering rule uses score, candidate creation time, and permanent number.

A facet appears on a term. A topic appears on a definition and is derived on the containing term. The tag identifies its scheme with skos:inScheme.

Hierarchy uses skos:broader and derived skos:narrower. Association uses symmetric skos:related. Active tags without a broader tag in the same scheme are top concepts. Full classification documents use skos:hasTopConcept and skos:topConceptOf. Vocabulary-page JSON-LD also lists top terms. Per-term documents describe tag schemes without enumerating all their top concepts.

Retired tags retain their IRI, scheme, and label with owl:deprecated true. Merged tags also name a replacement with dcterms:isReplacedBy.

External mapping assertions use skos:exactMatch, skos:closeMatch, skos:broadMatch, skos:narrowMatch, or skos:relatedMatch with an absolute IRI outside the identifier base. Internal relations use typed references. A topic-to-term equivalence uses skos:exactMatch in both directions and is one-to-one. Collection membership uses skos:member and does not imply a semantic mapping.

Labels, titles, descriptions, definition text, examples, and scope notes use English-tagged literals. Names, publisher, and status are untagged. Definition and revision numbers are xsd:positiveInteger. Dates use xsd:dateTime, except term creation dates, which use xsd:date. The legacy numeric JSON-LD term document retains an untyped creation-date string.

Each active example appears as a separate skos:example on the current revision. The featured selection does not limit the export. Identifier policy specifies resource paths.