- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Wed, 14 Nov 2001 09:45:05 -0600
- To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
- Cc: w3c-rdfcore-wg@w3.org
>At 07:38 PM 11/13/01 -0600, you wrote: >>I was under the impression that XML Schema datatypes DID satisfy >>the required conditions. To fail, we need the following >>circumstances: two datatypes D1 and D2 with the value space of D1 >>being a subset of that of D2, and the lexical space of D1 >>intersecting that of D2, and D1 having a different, and >>incompatible, lexical-to-value mapping on that intersection from >>that used by D2. > >I'm still bothered by the way you're describing this. The problem I >understand you're trying to avoid is that RDF(S) inferences may end >up licensing incompatible literal datatype mappings. Right. > I would expect the above to read: > >[[[ >... To fail, we need the following circumstances: two datatypes D1 and D2 > with any instance of D1 being inferable to also be an instance of D2, > ******************************************************************** >and the lexical space of D1 intersecting that of D2, and D1 having a >different, and incompatible, lexical-to-value mapping on that >intersection from that used by D2. >]]] > >In RDF(S), I understand that value space subsetting is not, of >itself, sufficient to draw subclass inferences. Am I wrong? (I >understand DAML+OIL is different.) No, you are right, and I was being sloppy. I should have said something like: ....the value space of D1 being an rdfs:subClassOf that of D2...., referring of course to the extensions. But you know, I feel that a datatyping scheme that would break - not just barf, but give wrong answers - when subclass reasoning was extensionally accurate, was far too 'fragile' for practical use, even if it could be made to work on paper. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Wednesday, 14 November 2001 10:44:43 UTC