Revision of the sugar proposal - w3c/rdf-star-wg GitHub Wiki
Named occurrences of triples as RDF reification
This syntax is simply a shorthand for RDF reification (or some variation thereof). In other words, any occurrence in the graph of a triple
<< :e | :s :p :o >> :p1 :o1 .
would be syntactic sugar for the following triples:
:e rdf-star:is-reification-of _:b
_:b rdf:subject :s .
_:b rdf:predicate :p .
_:b rdf:object :o .
:e :p1 :o1 .
with _:b
a fresh new blank node, unique within the RDF graph.
The abstract syntax would not need to be extended.
It is necessary to add a notion of syntactically "well-formed" RDF:
Definition: An RDF graph is reification well-formed iff:
- The object of each
rdf-star:is-reification-of
triple is a blank node. - Any blank node appearing as object of a
rdf-star:is-reification-of
triple occurs only in that triple and exactly once as subject of ardf:subject
triple, ardf:predicate
triple, and ardf:object
triple.
The notion of well-formedness does not impact reification-star-free RDF 1.1 graphs, and so it is fully backwards compatible.