- From: Andy Seaborne <andy@apache.org>
- Date: Wed, 10 Jan 2024 22:46:10 +0000
- To: RDF-star Working Group <public-rdf-star-wg@w3.org>
This is a variation of the consolidated triple/edges proposal. An issue with the "named occurrences" variation of the consolidate proposal is that given a name part of a named occurrence, there is no way to find out what the subject/predicate/object of the occurrence. There have been suggestions of having virtual property rdf:occurrenceOf (it can not appear in data) or adding an edge set into the RDF data model (a graph is no longer just a set of triples). In this variation, the RDF abstract data model has "occurrences sets" as RDF terms. An "occurrence set" for S,P,O is the set of all named occurrences that have S,P,O in those positions. There is one occurrence set for every triple. A named occurrences is a pair of (name, occurrence) where "occurrence" is member of an occurrence set. Occurrence sets replace triple terms. https://lists.w3.org/Archives/Public/public-rdf-star-wg/2023Dec/0033.html Named occurrences are not part of the RDF data model (abstract syntax). The syntax <<[ ]>> is used below for now to be different to triple term <<( )>>. Had that not been used already, it would be better as <<( )>> because () is often used for tuples. An implementation that wishes have great named occurrence performance can have data structure for (n,s,p,o) with indexed lookup operations. ## Turtle and N-Triples. << _:n | s p o >> :q :z . is a syntax form and is equivalent to the N-triples: _:n rdf:occurrenceOf <<[ :s :p :o ]>> . _:n :q :z . "memberOf" or variants on "member" don't look good because rdfs:member already exists. Now given a name "n" (blank node or URI) found by some means, then _:n rdf:occurrenceOf ?X . finds the occurrence set term, which has the subject/predicate and object. Annotation syntax applies as before. An RDF graph is a set of triples. There is no need for a virtual property. It may work to have a class of occurrences for S/P/O where the occurrence set is the class extension. Andy
Received on Wednesday, 10 January 2024 22:46:18 UTC