- From: <patrick.stickler@nokia.com>
- Date: Fri, 8 Feb 2002 09:21:57 +0000
- To: "ext Graham Klyne" <Graham.Klyne@MIMEsweeper.com>
- Cc: Pat Hayes <phayes@ai.uwf.edu>, Sergey Melnik <melnik@db.stanford.edu>, w3c-rdfcore-wg@w3.org
On Thursday, February 7, 2002, at 05:42 , ext Graham Klyne wrote: > I finally figured out why 'dtype' is needed, but a corresponding > extensions to 'range' is (maybe) not. > > 'type' inferences are intimately bound to subclassing, so the addition of > subclassing assertions that are quite reasonable with respect to the value > domains could completely mess up the datatyping. (I'm sure you explained > this Pat, but somehow I wasn't hearing.) > > This did make me wonder is there might not be a similar problem with > respect to 'range' and 'subPropertyOf': Yes. This was discussed awhile back in October within the context of some query API binding a literal to a superordinate property and loosing the datatyping context for correct interpretation. There was a good bit of discussion between Pat and I on this. C.f. http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Nov/0176.html I was myself until just recently unsure of the necessity of rdf:dtype, but I agree with you that it is needed. See also my recent query to Pat regarding the relationship between rdfs:range and rdf:type versus rdf:dtype, which ties into this issue of the semantics of rdfs:subPropertyOf. We may in fact need something like rdfs:drange ("deranged"? ;-) if rdfs:range only implies rdf:type and not rdf:dtype, otherwise, an application cannot be sure that there is a valid TDL pairing such that the lexical form is actually a member of the lexical space of the datatype -- as opposed to the bNode simply denoting a member of the value space of the datatype. It would be good, though, if we could include in the datatyping summary the "facts" about what rdfs:range, rdfs:subPropertyOf, etc. refer to (value spaces only). I try to capture the additional relations between lexical spaces and canonical lexical spaces in http://www-nrc.nokia.com/sw/RDFL.html and http://www-nrc.nokia.com/sw/RDFL.rdf which in some contexts is useful to know. And an application specific ontology that uses this datatype definition ontology to define its lexical datatypes: http://www-nrc.nokia.com/sw/MARS.rdf Cheers, Patrick
Received on Friday, 8 February 2002 04:21:08 UTC