The document discusses RDA vocabularies and their structure when represented in RDF. It explains that RDA properties are declared as a generalized vocabulary without explicit relationships to FRBR entities, and subproperties can then be explicitly related to FRBR entities. This allows the vocabularies to be used more broadly by both library and non-library implementers. It also discusses how aggregated RDA statements like publication statements are represented, either through pre-coordinated subproperties or by using RDA syntax encoding schemes. The generalized approach makes the vocabularies more flexible and extensible.