- From: Jim Hendler <hendler@cs.rpi.edu>
- Date: Mon, 10 Dec 2007 21:23:40 -0500
- To: Alan Ruttenberg <alanruttenberg@gmail.com>
- Cc: Michael Schneider <schneid@fzi.de>, "Owl Dev" <public-owl-dev@w3.org>, <boris.motik@comlab.ox.ac.uk>, <pfps@research.bell-labs.com>, <ian.horrocks@comlab.ox.ac.uk>, <dlm@ksl.stanford.edu>, <hans.teijgeler@quicknet.nl>
- Message-Id: <D00E6C40-64FA-402E-ABFC-0805D19AB703@cs.rpi.edu>
hmm, I think I do know the difference between an RDFS ontology and an OWL ontology in usage. If I am a user who comes from an RDF perspective or is not convinced of the value of OWL, I use a tool (usually a reasoner done procedurally) for RDFS. I am happy, my stuff works, and I use rdfs:class. I write webapps using Sparql, I create very large triple stores, I create a Web 3.0 startup and make money. I know some day it might be worth looking at OWL, but right now, I have no reason to - what it adds is not worth the extra work of converting things. On the other hand, I could be a user who has come into things from AI (like most of the people on the cc of this message). I'm convinced OWL is a good thing, and I use owl:class (and maybe even make my ontology expressive). When I create Aboxes to go with my ontology, I do them in RDF, and things seem to work okay. I tend not to use huge triple stores, and I tend to use a single ontology at a time. I work for a drug company or doing some "intranet" data integration. I like OWL DL. I also make money. So basically, we have two different groups who end up coming at things from different directions and not meeting in the middle. I'd love to see a fix, but I also understand the worldview that cannot live with this. but I'll tell you this based on experience and analysis of lots of stuff out there - telling people that the "right thing" to do is to use owl:class won't change much, because the people using rdfs:class to start with generally aren't coming from an OWL perspective, and therefore don't see a reason to change. So I see that if there was a solution in resolving these, we would make it easier for people to come to OWL - on the other hand, they're probably using inverseFunctional datatypes (the most commonly used construct we found in the RDFS and OWL Full documents) so it may not matter... JH p.s. finding a way to reconcile the two worldviews seems to be pretty much opposite the direction we're going w/OWL 1.1 - so maybe the "multi stack" solution is the best we can hope for. On Dec 10, 2007, at 1:23 PM, Alan Ruttenberg wrote: > Here's my understanding of the situation (if I've got it wrong > somewhere, please correct me). > > On Dec 8, 2007, at 3:20 PM, Michael Schneider wrote: > >> But, AFAICS, this would only become a real problem, if in this >> ontology some class is used as an individual (metamodelling). > > Or if the class has instances that are literals. > >> But in such a case, even after changing rdfs:Class to owl:Class, >> the resulting ontology would still be an OWL-Full ontology: There >> would, for example, be an 'rdf:type' triple with some class being >> at the individual position, or a class with an object or data >> property >> attached. > > The type triple is inferred in OWL Full - it doesn't have to be > explicit. > >> The OWL-DL reasoner would refuse to work in such a situation, of >> course. > > Because the triple would sometimes need to be inferred by the > reasoner itself, the DL reasoner can't detect the situation in all > cases. Strictly speaking, it can only detect the case where it > certainly shouldn't work. > >> So it looks to me that this recommendation is safe. > > I would say, no. However it might be ok if the user was warned, or > made an explicit declaration to that effect. > >> Or to summarize these recommendations in a simple rule of thumb: >> Assume 'rdfs:Class' in RDFS ontologies, assume 'owl:Class' in OWL >> ontologies. > > How do you tell the difference between and RDFS ontology and and > OWL ontology? > > I think what might "work" is commonly called "duck typing", as in, > if it walks like a duck and quacks like a duck, then.... > > The application in this case would be to look for an *explicit* > mention of something that might be only *inferred* in an OWL Full > ontology. Absent the explicit mention, you might assume that that > the author did not intend there for such statements to be inferred > either. This would be a change from the current semantics, and > possibly a reasonable ones, depending, IMO, on how the OWL Full > advocates voted. > > -Alan > "If we knew what we were doing, it wouldn't be called research, would it?." - Albert Einstein Prof James Hendler http://www.cs.rpi.edu/~hendler Tetherless World Constellation Chair Computer Science Dept Rensselaer Polytechnic Institute, Troy NY 12180
Received on Tuesday, 11 December 2007 02:23:46 UTC