rdf 2023-05-26 | Slack Archive

Eric Scott04:05:43

So I'm playing with owl property chain axioms, and I think maybe there's something I'm not getting. Among other things I have this definition:

:hasQuantity a owl:ObjectProperty ;
    owl:propertyChainAxiom (:primaryFigureOf :quantifiedAs) ;
    dc:description "X hasQuantity Y := X is the primary figure of a scan quantified as Y" ;
.

When I load the ontology and some test data into a Jena OWL-full reasoner, I get this:

> (igraph/query g (voc/prepend-prefix-declarations
                 "Select ?s ?o  Where {?s natlex:primaryFigureOf/natlex:quantifiedAs ?o}"))
({:s :natlex/TestTrajector, :o :natlex/TestQuantity})

But I had the impression that given the property chain axiom defined above this would be equivalent:

> (igraph/query g (voc/prepend-prefix-declarations
                   "Select ?s ?o Where {?s natlex:hasQuantity ?o}"))

()

Am I incorrect in that impression? All the other inferences are as expected.

quoll06:05:40

I’m guessing that the : prefix in your owl is defined to the same namespace that natlex is defined to in your queries, right?

Eric Scott11:05:56

Yes.

Eric Scott16:05:20

On closer inspection of the Jena docs, I don't see property chains mentioned on the table here: https://jena.apache.org/documentation/inference/index.html

quoll16:05:42

I haven’t used the Jena reasoner. But the way it’s written, it looks like it might be OWL, and not OWL 2

quoll16:05:54

(Property chains are OWL 2)

Eric Scott16:05:04

Ah. Good point

Eric Scott18:05:04

Funny that Jena still doesn't support OWL2.

quoll19:05:24

From memory, Jena supports multiple reasoning systems (rules and tableaux). Is that right? I know that Dave Reynolds did the rules based reasoner, but not much more than that. I would have a steep learning curve to look at a tableaux reasoner (I understand the theory, but never looked at an implementation), but updating the rules reasoner should be accessible. This is because OWL2 has a full set of rules for RL. The question is… do I try this myself, or do I convince someone else to do it instead 🙂

Eric Scott00:05:20

Yeah I'm really hoping I don't need to get that close to the metal. :-)

simongray07:05:21

Anybody here have any experience using http://sparnatural.eu/ ? It looks like an amazing query builder for RDF triplestores.

👌 4

simongray07:05:21

One thing I noticed is that is is not accessible by keyboard at all, which unfortunately means I would be violating the accessibility directive should I choose to use it. Perhaps an exception can be made, but it really is a shame to build such an elaborate UI and never once consider keyboard users.

rickmoynihan08:05:31

Thanks for sharing… looks like an interesting idea

curtosis20:05:15

Do any of you have an RDF training resource that you like? I need to get some of the junior folks on one of my teams a solid grounding (and can’t spare the time to create & give the training myself). I’m familiar with some of the usual suspects, but curious to see what others have found.

2023-05-26

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