rdf 2023-05-19 | Slack Archive

quoll12:05:50

I spoke with Ora about RDF* and SPARQL* last week. He is very interested in the output of the working group on this, and indeed the working group announced something just this week https://www.w3.org/blog/news/archives/9906

🎉 1

rickmoynihan13:05:18

I want to like RDF*, and experimented modelling with it a while back but I find the semantics as they stand confusing. I was also trying to use it via stardog; but found it frustrating that their implementation also didn’t support the spec… I can’t recall the details, but there’s a lot of complexity in the relation to reification, d-entailment and quoted and asserted triples. I think graphs and reification can be used to model most things you might want to use RDF* for.

quoll14:05:53

The problem with reification is that it wasn’t designed with the intent of actually asserting the triples. However, if reification were entailed then it was clumsy for accessing the ID. For instance, if I wanted to state Eric’s example of:

[<Harry> <hasSpouse> <Meghan>] <start> <2018>

Then I would need SPARQL like:

INSERT { ?triple <start> "2018"^^xsd:gYear }
WHERE { ?triple rdfs:subject <Harry> ;
                rdfs:predicate <hasSpouse> ;
                rdfs:object <Meghan> }

It works, but yuck. Also, there’s no way to write this in Turtle, since it’s referring to an implicitly generated value for ?triple The other problem with implicit reification is making statements about statements that don’t exist. OTOH, explicit reification may work, but it’s extremely verbose and expensive. The designers of reification (at least, people like Ora) did not expect people to declare it explicitly.

quoll14:05:01

Oh! The latest working draft for RDFS 1.2 is now the official document??? When I go to RDFS 1.0 it directs me to the link: https://www.w3.org/TR/rdf-schema/ And when I go to that page, it’s showing me the Working Draft! This bothers me greatly. It’s not an official recommendation yet!

quoll14:05:08

I’m thinking someone has messed up. Working Drafts are not Recommendations

quoll14:05:11

Yup. Andy Seaborne already commented on it

2023-05-19

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