Namespace Prefixes

The FAIR² specification reuses terms from several external vocabularies. Every fair2.json producer SHOULD declare the prefixes below in their @context, and consumers SHOULD expect these bindings to resolve to the URIs given here.

Canonical prefix table

Prefix	URI
cr:	http://mlcommons.org/croissant/
cro:	http://purl.obolibrary.org/obo/CRO_
credit:	http://purl.org/credit/ontology#CREDIT_
dct:	http://purl.org/dc/terms/
fair2:	https://fair2.ai/ns/
fair2s:	https://fair2.ai/shapes/
prov:	http://www.w3.org/ns/prov#
rai:	http://mlcommons.org/croissant/RAI/
rdfs:	http://www.w3.org/2000/01/rdf-schema#
sc: / schema:	https://schema.org/
skos:	http://www.w3.org/2004/02/skos/core#
xsd:	http://www.w3.org/2001/XMLSchema#

Retired prefixes

• mlc: — previously used for MLCommons Croissant terms. Retired in favour of cr: (same target URI). Any mlc: occurrence in producer output is an error.

Notes on specific prefixes

• credit: resolves to the CRediT taxonomy hosted at purl.org. Role identifiers are of the form credit:Conceptualization, credit:DataCuration, etc. This URI form is the canonical FAIR² binding; downstream tooling that historically used the NISO z39.104 URIs (http://www.niso.org/publications/z39104-2022-credit#...) SHOULD migrate.

• fair2: terms resolve against the FAIR² ontology. Property and class definitions live in ontologies/fair2_ontology.ttl.

• fair2s: is reserved for SHACL shape identifiers defined in shapes/turtle/. It is distinct from the data-model prefix fair2:.

Canonical @context reference

The authoritative @context block FAIR² producers should reference is context/metadata/fair2_context.json. It aliases every term used in the FAIR² data model so that fair2.json payloads can be written without bare prefixed forms in their bodies.