- From: Danny Ayers <danny.ayers@gmail.com>
- Date: Fri, 11 Feb 2005 11:57:52 +0100
- To: Henry Story <henry.story@bblfish.net>
- Cc: semantic-web@w3.org, yzqu@seu.edu.cn
On Fri, 11 Feb 2005 10:59:49 +0100, Henry Story <henry.story@bblfish.net> wrote: > I don't understand. Why would it have to be that for > > _blank ---relationR--> <http://bblfish.net/> > |------owner-------> "Henry Story" > > to entail [1] the graph > > <http://bblfish.net> ----owner----> "Henry Story" > > _blank and <http://bblfish.net/> only need to be in the > same classes? Is that because you are assuming that elements > of the same class share all the properties of the class? I could be wrong, but the way I read it is that for this specific case, all that is necessary is for _blank to be in a class X for which: forall [individual in X] ----owner----> "Henry Story" Generalising from there, if you want _blank to have all the properties of <http://bblfish.net/> then you'd have _blank being in all the same classes as <http://bblfish.net/> (possibly an infinite number). This certainly holds for resources that are the owl:sameAs <http://bblfish.net/>, but I don't believe it necessary follows from being in all the same classes that there's an identity relationship between the individuals. (Although this could be an axiom somewhere in the small print ;-) I suspect this falls outside what is covered by RDF/OWL, I think Yuzhong Qu may have found the right relation with quotient (I found the ref [1] which sounds about right). I'd guess that the rule that 'X is member of all same classes as Y' => 'X is Y' would make hard work for decidability - you'd have to be able to enumerate all the classes. In practice I would think it would be reasonable to use the identity to go the other way: <atom:entry> <atom:id rdf:resource="http://bblfish.net/" /> </atom:entry> <atom:id rdf:type="http://www.w3.org/2002/07/owl#ObjectProperty> <owl:equivalentProperty rdf:resource="http://www.w3.org/2002/07/owl#sameAs"> </atom:id> But I'm sure whether this would still be in OWL DL. Cheers, Danny. [1] http://mathworld.wolfram.com/QuotientSpace.html -- http://dannyayers.com
Received on Friday, 11 February 2005 10:57:54 UTC