- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Thu, 24 Apr 2003 19:26:11 -0400 (EDT)
- To: heflin@cse.lehigh.edu
- Cc: www-webont-wg@w3.org
From: Jeff Heflin <heflin@cse.lehigh.edu> Subject: Re: Case for Reinstatement of Qualified Cardinality Restrictions Date: Thu, 24 Apr 2003 15:46:04 -0400 > Sorry, this issue keeps nagging at me... > > I looked at Sect. 5 of S&AS (RDF-compatible semantics) and it seems that > it gives semantics to Restriction resources that have some combination > of cardinality, someValuesFrom and allValuesFrom properties, such as in > the example below. > > <owl:Restriction> > <owl:onProperty rdf:resource="⪚hasDigit"/> > <owl:cardinality rdf:datatype="&xsd;int">5</owl:cardinality> > <owl:allValuesFrom rdf:resource="⪚Digit" /> > <owl:someValuesFrom rdf:resource="⪚Finger" /> > </owl:Restriction> > > Furthermore, it looks like the semantics would be the same as if you had > an intersection of: > > <owl:Restriction> > <owl:onProperty rdf:resource="⪚hasDigit"/> > <owl:cardinality rdf:datatype="&xsd;int">5</owl:cardinality> > </owl:Restriction> > > <owl:Restriction> > <owl:onProperty rdf:resource="⪚hasDigit"/> > <owl:allValuesFrom rdf:resource="⪚Digit" /> > </owl:Restriction> > > <owl:Restriction> > <owl:onProperty rdf:resource="⪚hasDigit"/> > <owl:someValuesFrom rdf:resource="⪚Finger" /> > </owl:Restriction> No. It is different. The first implies that the extension of the three just above are all the same. > The reason is that in the section called "Conditions on OWL > restrictions" the semantics for each of these types of restrictions only > depends on having two triples (onProperty and something else) with the > same subject, and these conditions are met in the "jumbo restriction" > above. > > However, this seems to contradict Section 4 (Mapping to RDF Graphs) > which does not provide a translation into the "jumbo restriction" and > therefore implies that it doesn't have semantics, and also isn't even > valid syntax. No, all that this indicates is that the first is not in OWL DL. > This is very confusing. I thought the mapping to RDF defined the RDF > syntax, but that doesn't seem to be the case. Does it just define the > syntax for OWL DL, and not OWL Full? The mapping to RDF defines the syntax for OWL DL and OWL Lite. > Even if this was the case, it would > seem that the RDF combatible semantics and the abstract semantics > disagree on what constitutes an OWL DL graph (take this Restriction case > as an example). Is it the case that the RDF compatible semantics only > apply to some subset of RDF graphs as determined by the transformation > in Section 4? The RDF-compatible smenatics applies for all RDF graphs. > Help, I think my brain is about to explode. :-( Welcome to the wonderful world of triples. :-) > Jeff peter
Received on Thursday, 24 April 2003 19:26:24 UTC