From: Richard Fikes (fikes@ksl.stanford.edu)
Date: 10/24/01
> >> Sorry to be dense, but how does one state "there is something colored > >> red" in DAML+OIL? > > > >The simple answer is that you can't without either naming it (i.e., > >asserting that some named individual is red) or connecting it to some > >named individual via properties. This "collapsed model property" is > >one of the basic properties of description logics on which their > >decision procedures depend. > > Hmm. This seems easy in RDF: > > _:xxx hasColor Red . > > That would seem to imply that RDF can express something that DAML+OIL > cannot express! Which is fine, I guess, but it doesn't jibe with what > I had (perhaps naively) thought was the intended relationship between > RDF/S and DAML+OIL. I would very much like to see this issue resolved. However, it seems to me that cardinality constraints provide us with the same (or at least analogous) issues regarding bindings to query variables in query results. I.e., does a query that asks for all the parents of Joe (as described in my previous message), to a KB that does not name the parents of Joe get back two bindings to constants created by the query answering agent to represent the parents of Joe or does it get back no bindings plus an indicator that there are exactly two answers to the query? Richard
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