Relations Datastream
The relations datastream (RELS-EXT) is defined by FoxML. It uses Resource Description Framework (RDF) to describe the relations.
For FedoraObjects the RELS-EXT datastream is optional, but for a DOMS object, the RELS-EXT datastream is mandatory. This is required by the typechecking mechanism.
DOMS RDF uses the controlled vocabulary from Fedora, together with a generic DOMS controlled vocabulary and collection-specific controlled vocabularies.
The mandatory relations for objects of a specified type are defined by the TYPE object.