Re: DBpedia now available as triple pattern fragments

On Oct 29, 2014, at 6:58 AM, Ruben Verborgh <ruben.verborgh@ugent.be> wrote:

>> The above doc describes paging over "blank-node-free" triples. Is that to simplify ordering?
> 
> The main reason is that blank nodes cannot be identified across different requests.
> For instance, if I request the triple pattern fragment for ?x rdf:type foaf:Person
> and the results contain _:b0 rdf;:ype foaf:Person,
> how can I ask for more data about this person?
> I cannot ask for _:b0 ?p ?o,
> because the local identifier _:b0 was only valid in the context of the first response.
> 
> We solve this by translating all blank nodes to IRIs, following [1].

Ruben,

I’m interested to see that you’re skolemizing blank nodes in the DBPedia Fragments data as I think this addresses some obvious challenges to using Triple Pattern Fragments with arbitrary RDF. However, I don’t see any mention of doing this in the Triple Pattern Fragments spec. Would you consider adding this as a recommendation (“SHOULD”) to the spec, with a description of the problem it solves?

thanks,
.greg