SI is a subject identifier service providing URI endpoints for Wandora and similar applications. The service returns a web page for all known and unknown subject identifier URIs within the domain and path. Subject resources of known identifiers may have more information about the subject.
Default occurrence
http://wandora.org/si/core/default-occurrence
Sometimes the user may want to attach occurrences into topics but doesn't care occurrence's type. This is a subject that reifies a default type topic for occurrences.