<What I am trying to figure out is prior to this declaration, owl:inverseOf only works one-way, after this is defined, owl:inverseOf will work in both directions.>
Yes. Although, this may not be the easiest example to understand because owl:inverseOf is already defined as symmetric in the OWL standard. <If I were to federate across two repositories where one of them redefined the owl:inverseOf in this manner, it would be change at a global level.> Yes, conceptually this is a "global" change in the sense that it applies to all the triples that use this property as a predicate. Practically, however, there are a lot of architectural questions and possibilities implicit in this example. What does it mean to federate across 2 repositories? Run a query across two repositories? How will the query be ran, what is the federation strategy? What role inferencing plays in responding to the query? When is inferencing performed, etc. So in the practical sense, assertions in one repository may or may not make an impact on the inferences in another repository. It all depends on how you architect the system. Regards, Irene Polikoff Executive Partner, TopQuadrant tel: 914-777-0888/ cell: 914-329-8576 www.topquadrant.com -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Scott Henninger Sent: Wednesday, December 10, 2008 11:53 AM To: TopBraid Composer Users Subject: [tbc-users] Re: question about owl:inverseOf rdf:type owl:SymetricProperty . Oops, you're right. So is the book. It's a type def stating that the inverseOf property is a type of property (symmetric). Sorry to confuse things. It's still the case, though, that owl:inverseOf is not being redefined. We've added a definition to owl:inverseOf that will create a new triple each time it is used. I.e. if you have a triple: xyz owl:inverseOf abc then 'owl:inverseOf rdf:type owl:SymmetricProperty' will add the triple abc owl:inverseOf xyz ...as it would for any triple that uses owl:inverseOf. the definition of owl:inverseOf does not change. As this is a forum for TopBraid Composer discussion and not general Semantic Web issues, I'd suggest taking a look at http://www.workingontologist.org/ or contactign the authors. -- Scott On Dec 10, 11:36 am, "tk blast" <[EMAIL PROTECTED]> wrote: > Scott, this is very helpful and I can see how SPARQL CONTRUCT would be > useful as yet another method of triple creation. > > If there is a problem with my triple then there is an errata in the > Allemang & Hendler book because the triple is taken directly from the > solution on page 131. I'll quote it here so that it may be useful to others: > > > --------------quoted from book begin----------------- Since we want > > owl:inverseOf to work in both directions, this can be done easily by > > asserting that owl:inverseOf is its own inverse, thus: > > owl:inverseOf owl:inverseOf owl:inverseOf . > > > You might have done a double take when you read that owl:inverseOf > > is its own inverse. Fortunately, we have a more readable and > > somewhat more understandable way to say this - namely: > > owl:inverseOf rdf:type owl:SymmetricProperty . > > --------------quoted from book end----------------- > > What I am trying to figure out is prior to this declaration, > owl:inverseOf only works one-way, after this is defined, owl:inverseOf > will work in both directions. > > If I were to fererate across two respostiries where one of them > redefined the owl:inverseOf in this manner, it would be change at a global level. > > --tk > > On Wed, Dec 10, 2008 at 8:15 AM, Scott Henninger > <[EMAIL PROTECTED] > > > > > wrote: > > > Hello; There is a problem with your triple in that owl:inverseOf is > > a property and is used as the subject in "owl:inverseOf rdf:type > > owl:SymmetricProperty". That's not allowed, so the redefinition > > couldn't happen. > > > In addition, redefining rdf/rdfs/owl terms will not happen via > > inference. You can extend these - for example creating a > > subproperty of rdfs:label. And this is the intent of the Allemang & > > Hendler pages you cite. > > > In general, though, inferencing can be aggressive and the ontology > >has to be designed with care. This is one of the reasons > >TopQuadrant is spending resources to use SPARQL CONSTRUCT, for > >example, to provide infrastructure for more controlled > >"inferencing". Take a look at http://spinrdf.org, which is part of these overall efforts. > > > -- Scott > > > On Dec 9, 6:15 pm, "tk blast" <[EMAIL PROTECTED]> wrote: > > > Hello fellow, > > > in the Allemang/Hendler book, on page 130-131 there is a > > > discussion about OWL to Extend OWL. > > > I want to make sure I understand the ramification of this type of > > assertion. > > > > If I were to import a file.owl that contained the triple: > > > owl:inverseOf rdf:type owl:SymmetricProperty . > > > it would redefine owl:inverseOf for all instances right? > > > > I guess what i am asking is when one goes about redefining items > > > in the > > owl > > > namespace, > > > appropriate care must be given to the scope of those assertions. > > > Just > > like > > > rdfs:domain and rdfs:range, the inferences are aggresive and must > > > be > > treated > > > with care. > > > > --tk > > > > -- > > > > "The nervous system organizes itself so as to compute a stable > > > reality" - Maturana & Varela > > -- > > "The nervous system organizes itself so as to compute a stable > reality" - Maturana & Varela --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "TopBraid Composer Users" group. 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