About the RDA Registry and vocabularies

• 4-fold path
• Datatype and object element sets
• Element set families
• Class hierarchies
• Relationship matrix

4-fold path

The RDA Development Team is developing extensions to the RDA element sets to accommodate data from the "4-fold path".

There are three methods for using a string to identify a related entity:

• An unstructured description: a plain literal, for example a free text note or a transcription.
• A structured description: a literal typed with a form of syntax encoding scheme that aggregates literal values from other elements, for example a name/title access point.
• An identifier: a literal that may be typed with a form of syntax encoding scheme that aggregates literal values from other elements, for example an ISBN or local identifier.

The fourth method uses a URI to identify the related entity as a linked data thing.