- From: Sandro Hawke <sandro@w3.org>
- Date: Thu, 24 Mar 2011 12:17:07 -0400
- To: Michael Schneider <schneid@fzi.de>
- Cc: Pat Hayes <phayes@ihmc.us>, Graham Klyne <GK-lists@ninebynine.org>, Dieter Fensel <dieter.fensel@sti2.at>, Enrico Franconi <franconi@inf.unibz.it>, Hugh Glaser <hg@ecs.soton.ac.uk>, Mark Wallace <mwallace@modusoperandi.com>, Alan Ruttenberg <alanruttenberg@gmail.com>, Reto Bachmann-Gmuer <reto.bachmann@trialox.org>, Ivan Shmakov <oneingray@gmail.com>, Ivan Shmakov <ivan@main.uusia.org>, "<semantic-web@w3.org>" <semantic-web@w3.org>
On Thu, 2011-03-24 at 16:07 +0000, Michael Schneider wrote:
> Hi Sandro!
>
> Sandro Hawke wrote:
>
> > Is there something in the OWL specs that says OWL doesn't work
> > (or that we're no longer in DL) if the nodes composing the lists
> > are not blank? That would be a problem.
>
> In the OWL 2 Mapping to RDF Graphs at
>
> <http://www.w3.org/TR/2009/REC-owl2-mapping-to-rdf-20091027/>
>
> many of the RDF graph patterns on the left-hand-side of inverse mapping rules from RDF to the Functional Syntax are only defined for blank nodes. See, for instance, Table 16, where you can see the differences: there are some rules that use a string "*:x", which stands for an IRI according to the definition in Chap 1, some rules which can be used with both IRIs and blank nodes, as denoted by the string "x", and some of the rules in that table are really only defined for blank nodes only, denoted by string "_:x". You can find many more examples for blank node-only rules in the other tables.
>
> Specifically for lists, their inverse mapping is treated by Table 3, which only handles the case of blank nodes.
>
> OWL 2 DL parsers may, of course, decide to relax on this and also parse structures having URIs instead of blank nodes. But, strictly speaking, such RDF graphs do not count as valid OWL 2 DL ontologies in RDF graph form.
Well, that's annoying. Do you know of a technical reason for doing it
this way, or was it just that no one saw a reason to allow nonblank
nodes? Sigh. I guess it's a small problem compared to the related
problem that (as I recall) people can't even use RDF Lists for data in
OWL DL. *Even Bigger Sigh*.
I guess the important question: is OWL 2 Full okay with people
Skolemizing the ontology?
-- Sandro
Received on Thursday, 24 March 2011 16:17:27 UTC