Rdf.SolidSourceElements of http://www.w3.org/ns/solid/terms#
A resource containing time ordered items and sub-containers. Sub-containers may be desirable in file based systems to split the timeline into logical components e.g. /yyyy-mm-dd/ as used in ISO 8061.
A index of type registries for resources. Applications can register the RDF type they use and list them in the index resource.
Indicates if a message has been read or not. This property should have a boolean datatype.