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    Namespaces & prefixes

    The schema-derived ontology uses the stable https://opda.org.uk/pdtf/ identifier namespace with a deliberate kind-split (ADR-0006): each kind of resource — term, SKOS scheme, SHACL shape, named graph, governance record — lives in its own namespace segment so local names cannot collide. This technical publication does not make the corpus an endorsed scheme. Reader representations are documented by ADR-0044; for example, https://opda.org.uk/pdtf/Property has the page /pdtf/Property. Identifier identity and representation paths remain distinct.

    For portable static publication, the LeaseTerm/leaseTerm pair is represented at distinct lowercase, type-scoped paths.

    This page describes the preserved schema-derived corpus. For the new governed model, read Namespaces and identifiers and ODR-0065. Its selected /ns/ and /id/ scheme does not migrate this corpus or the existing Property Pack candidate.

    OPDA namespaces (the kind-split)

    PrefixNamespaceHoldsExample
    opda: https://opda.org.uk/pdtf/ OWL classes + object/datatype properties (the flat term namespace) — 41 classes, 280 properties https://opda.org.uk/pdtf/Property
    opda-v: https://opda.org.uk/pdtf/scheme/ SKOS concept schemes and their concepts — 48 schemes, 319 concepts https://opda.org.uk/pdtf/scheme/TenureScheme
    opda-sh: https://opda.org.uk/pdtf/shape/ SHACL node shapes — 402 shapes https://opda.org.uk/pdtf/shape/PropertyIdentityKeyShape
    (graphs) https://opda.org.uk/pdtf/graph/ Named graphs — one per module TTL, populated by the Fuseki loader https://opda.org.uk/pdtf/graph/property
    (harness) https://opda.org.uk/pdtf/harness/ Governance provenance — ODR/ADR sections and overlay-form leaves cited via dct:source https://opda.org.uk/pdtf/harness/odr/ODR-0005/section-2a

    Why the kind-split (ADR-0006)

    The ruling (directing authority, 2026-06-02) is collision-avoidance under a flat term namespace. A property such as opda:role at https://opda.org.uk/pdtf/role must not collide with the Participant Role concept scheme — so schemes resolve under https://opda.org.uk/pdtf/scheme/ and their members under https://opda.org.uk/pdtf/scheme/role/Buyer; shapes under https://opda.org.uk/pdtf/shape/. The OWL term namespace stays flat (classes PascalCase, properties camelCase), which keeps the dereferenceable /pdtf/{LocalName} contract simple. The single source of truth is tools/opda-gen/src/opda_gen/namespaces.py; the GRLC API and this site both resolve against it (the pre-migration w3id.org/opda/# namespace is retired).

    Standard external vocabularies

    The ontology reuses these W3C / community vocabularies rather than re-minting their terms:

    PrefixNamespace
    owl:http://www.w3.org/2002/07/owl#
    rdf:http://www.w3.org/1999/02/22-rdf-syntax-ns#
    rdfs:http://www.w3.org/2000/01/rdf-schema#
    skos:http://www.w3.org/2004/02/skos/core#
    sh:http://www.w3.org/ns/shacl#
    dct:http://purl.org/dc/terms/
    xsd:http://www.w3.org/2001/XMLSchema#
    prov:http://www.w3.org/ns/prov#
    dpv:https://w3id.org/dpv#

    The opda-v: scheme split is explained in depth on Vocabularies (SKOS); the literal datatypes are on Datatypes; consuming the ontology over content negotiation is on Consume the ontology. Full index: Index & glossary.

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