- From: Michael Schneider <schneid@fzi.de>
- Date: Tue, 24 May 2011 21:34:01 +0200
- To: <uschold@gmail.com>
- CC: <antoine.zimmermann@insa-lyon.fr>, <markus.kroetzsch@comlab.ox.ac.uk>, W3C SWIG Mailing-List <semantic-web@w3.org>
[Strange, this whole discussion on OWL Full was captured by my SPAM filter - what does this mean? :->] Am 19.05.2011 19:42, schrieb Michael F Uschold: > Do you know of a more practice-focused > paper that gives examples of what you can and cannot do with OWL2 > metamodelling, compared to OWL-Full? By "can do" you certainly mean "infer", because the additional entailments of OWL 2 Full over OWL 2 DL are the distinctive aspect here (syntactically, you can write down quite a couple of things in OWL 2 DL that look like metamodeling without getting your parser upset). So let's make a few not too complicated examples for OWL 2 Full metamodeling-based entailments (sorry, no paper (yet)). You can already get a few such entailments from valid OWL 2 DL ontologies that are themselves valid OWL 2 DL ontologies but which are not covered by the semantics of OWL 2 DL (the OWL 2 Direct Semantics). The easiest one's are those derived from "rdf:type - owl:sameAs" chains, such as (01) Premise: dbpedia:Eagle owl:sameAs freebase:Eagle . ex:Harry rdf:type dbpedia:Eagle . Conclusion (OWL Full only): ex:Harry rdf:type freebase:Eagle . It's funny to note that the owl:sameAs link in the premise above really exists in DBPedia; the owl:type triple doesn't, though. But you can have a look in a previous mail that I wrote (actually, it's three mails), where I give a "live" example of such a chain (with countries instead of eagles, and England instead of Harry), and afterwards find by SPARQLing that there are literally thousands(!) of such chains in DBPedia and other LOD cloud nodes: <http://lists.w3.org/Archives/Public/public-owl-dev/2010OctDec/0057.html> But you will only experience the real power of the dark side, er, OWL Full, if you leave the OWL 2 DL syntactic fragment and allow to use OWL vocabulary, such as "rdf:type", as normal entities. It is then easily possible to define a "ex:metatype" property that relates individuals with their meta classes by (02) ex:metatype owl:propertyChainAxiom (rdf:type rdf:type) . Using this with the assertions (03) ex:Eagle rdf:type ex:Species . ex:Harry rdf:type ex:Eagle . yields (04) ex:Eagle ex:metatype ex:Species . You can now encode lots of things where the three ontological layers of individuals, classes and meta-classes are related somehow, and get entailments from it. For example, you can model the following: "A species for which there are still member instances is an active species." by (05) [ owl:intersectionOf ( ex:Species [ owl:someValuesFrom owl:Thing ; owl:onProperty [owl:inverseOf rdf:type] ] ) ] rdfs:subClassOf ex:ActiveSpecies . This together with (03) gives you that eagles are (still) active species, because of Harry: (06) ex:Eagle rdf:type ex:ActiveSpecies . What a relief! Ok, this should be enough for a start. I have many other examples in draft form, including much more sophisticated ones, ready to be written up, so you might still get your paper some day. :-) Now, if you believe that this is all foolish, impossible and blasphemic stuff, just let me tell you that all my examples above are properly covered by the OWL 2 RL/RDF rules [1], which is a "light-weight" sub language of OWL 2 Full, so you don't really need a full-fledged OWL 2 Full reasoner for processing them. And if you don't believe this, use Ivan Herman's online RL reasoner at <http://www.ivan-herman.net/Misc/2008/owlrl/> to check (make sure to define all the additional namespace prefixes!). Or you can likewise use OWLIM (with the OWL 2 RL ruleset) or any other of the myriads of OWL 2 RL/RDF rule reasoners that are now available, which should give you the same results. Actually, the last example (05/06) is pretty much at the limit of the RL rules, and I can easily rephrase it in a way that it falls off from RL but still keeps within OWL 2 Full. But don't despair: even those harder reasoning examples can be managed. But that's a different story and won't be told today! :-) Cheers, Michael [1] OWL 2 RL/RDF rules: <http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules> -- Dipl.-Inform. Michael Schneider Research Scientist, Information Process Engineering (IPE) Tel : +49-721-9654-726 Fax : +49-721-9654-727 Email: michael.schneider@fzi.de WWW : http://www.fzi.de/michael.schneider ============================================================================== FZI Forschungszentrum Informatik an der Universität Karlsruhe Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe Tel.: +49-721-9654-0, Fax: +49-721-9654-959 Stiftung des bürgerlichen Rechts Stiftung Az: 14-0563.1 Regierungspräsidium Karlsruhe Vorstand: Dipl. Wi.-Ing. Michael Flor, Prof. Dr. rer. nat. Ralf Reussner, Prof. Dr. rer. nat. Dr. h.c. Wolffried Stucky, Prof. Dr. rer. nat. Rudi Studer Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus ==============================================================================
Received on Tuesday, 24 May 2011 19:34:31 UTC