Another approach to the non-reification problem...

Hi guys,

I just saw a relatively similar question coming up on the SWIG mailing list. The solution put forward was to use named graphs. (I believe NG-s were not yet fully finalized as standards when the the Prov WG was working.)

To make it a bit abstract (Ben, you tell me if this understanding of the problem is what we are looking for.) We have a triple:

 ex:A ex:B ex:C.

Where ex:B is of class ex:Prop

And we want, somehow to attach additional information on the triple itself (eg, say that the triple's permissible time interval is such and such).

1. The Prov solution:

defined a 'qualified class', ie, ex:qualifiedProp.

ex:B
   rdf:type    ex:qualifiedProp;
   ex:source ex:A;
   ex:target  ex:C;
   … add any additional triples here

2. The NG solution:

   ex:mySpecificTriple { ex:A ex:B ex:C }.
   ex:mySpecificTriple
      … add any additional triples here

Overall:

- both are convoluted
- both are unfriendly for JSON-LD, but both can be encoded.
- the NG looks nicer in turtle, oops, not, it is then TriG (and most of the systems out there understand NG-s)
- conceptually, if NG-s are used, a full ODRL is not an RDF Graph, but an RDF Dataset[1]
- both represent, I presume, an extra complication for the semantics document, and I am not sure whether there are OWL formalizations of datasets (the formal specification of Datasets came after the publication of OWL2)
- NG-s are somewhat cleaner and more in line with the RDF standards...

Hope this helps!

Cheers

Ivan


[1] https://www.w3.org/TR/rdf11-concepts/#section-dataset

----
Ivan Herman, W3C
Digital Publishing Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
ORCID ID: http://orcid.org/0000-0003-0782-2704