- From: Michael Schneider <schneid@fzi.de>
- Date: Sun, 9 Dec 2007 12:43:02 +0100
- To: "Hans Teijgeler" <hans.teijgeler@quicknet.nl>
- Cc: "Owl Dev" <public-owl-dev@w3.org>, <hendler@cs.rpi.edu>, <alanruttenberg@gmail.com>, <boris.motik@comlab.ox.ac.uk>, <pfps@research.bell-labs.com>, <ian.horrocks@comlab.ox.ac.uk>, <dlm@ksl.stanford.edu>
Hi, Hans! >-----Original Message----- >From: public-owl-dev-request@w3.org >[mailto:public-owl-dev-request@w3.org] On Behalf Of Hans Teijgeler >Sent: Saturday, December 08, 2007 6:42 PM >To: Michael Schneider >Cc: 'Owl Dev'; hendler@cs.rpi.edu; alanruttenberg@gmail.com; >boris.motik@comlab.ox.ac.uk; pfps@research.bell-labs.com; >ian.horrocks@comlab.ox.ac.uk; dlm@ksl.stanford.edu >Subject: RE: [OWLWG-COMMENT] ISSUE-55 (owl:class) > > >Hi Michael, > >Clear analysis, Thanks! > perhaps with some conflicting statements: >1) "If one creates a new OWL ontology, one always should use >'owl:Class' >instead of 'rdfs:Class'"; >2) "Assume 'rdfs:Class' in RDFS ontologies, assume 'owl:Class' in OWL >ontologies"; >3) "OWL-Full is meant to be a semantic extension to RDFS. >Thus, in OWL-Full >owl:Class is the same as rdfs:Class." > >So what's the final outcome? > >We have built, and are still building, OWL ontologies in which >"instance-of" >chains are possible. > So we deal with OWL Full. Yes, in fact! So be it. >But does this mean that we'd have to change owl:Classes back to >rdfs:Classes, No, you don't have to (although you are allowed to do so because in OWL-Full owl:Class is the same as rdfs:Class). I argued for quite the opposite: If you have rdfs:Classes in your OWL-Full ontology, then you may/should change every occurrence of 'rdfs:Class' to 'owl:Class'! >following the rationale: >- "OWL Full is a semantic extension of RDFS"; This is true... >- hence an OWL Full ontology is an RDFS ontology; No, I think this is a misunderstanding. It is the other way around: Every RDFS ontology is also an OWL-Full ontology (formally a little broken, because RDFS ontologies miss an OWL ontology header, but this is not relevant for our semantics related discussion here). When I said that OWL-Full is a semantic extension to RDFS, then I meant that OWL-Full knows about all semantic conditions of RDFS, as given in the RDF semantics spec, but OWL-Full also introduces additional semantic conditions which are unknown to RDFS. These semantic conditions determine the set of entailments you receive from a given ontology. So for a given RDFS ontology, OWL-Full semantics will result in (at least) all entailments which you would get from RDFS semantics. >- "assume rdfs:Class in RDFS ontologies" ? >Or am I completely off-track? As long as you produce OWL ontologies (Lite, DL or Full), it is perfectly save to use 'owl:Class' in all situations. This was the message of my previous mail. So you never have to wonder about when to use 'rdfs:Class' and when not. And people using your ontology do not have to wonder about your intentions behind the use of 'rdfs:Class', when they find it being used in certain places of your ontology. There will always only be 'owl:Class'. Or as Bob Marley would express it: "No rdfs:Class, no cry!" ;-) Only if you really intend to produce genuine RDFS ontologies, then you need to use 'rdfs:Class', because RDFS reasoners do not know about 'owl:Class'. So just go on with using 'owl:Class' everywhere in all your OWL ontologies, and you will always be on the right track! :) > >Regards, >Hans Cheers, Michael -- Dipl.-Inform. Michael Schneider FZI Forschungszentrum Informatik Karlsruhe Abtl. Information Process Engineering (IPE) Tel : +49-721-9654-726 Fax : +49-721-9654-727 Email: Michael.Schneider@fzi.de Web : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555 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 Az: 14-0563.1 Regierungspräsidium Karlsruhe Vorstand: Rüdiger Dillmann, Michael Flor, Jivka Ovtcharova, Rudi Studer Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
Received on Sunday, 9 December 2007 11:43:22 UTC