- From: Pat Hayes <phayes@ihmc.us>
- Date: Thu, 19 Jan 2006 11:33:33 -0600
- To: Enrico Franconi <franconi@inf.unibz.it>
- Cc: Dan Connolly <connolly@w3.org>, Bijan Parsia <bparsia@isr.umd.edu>, RDF Data Access Working Group <public-rdf-dawg@w3.org>
>On 18 Jan 2006, at 23:12, Pat Hayes wrote: >>>>SELECT ?x WHERE {:a rdf:type ?x .} >>> >>>Look, this is not a legal OWL-DL query. >> >>This query pattern has legal OWL-DL instances, so why is it not a >>legal OWL-DL query? > >Look, we already agreed that we are not here to do research. Of course. You miss my point. I was simply following the general pattern of how SPARQL queries are defined, using our most recent attempt at an 'entailment-based' general form of definition, and applying that to OWL-DL as described in the OWL spec, and seeing what we finish up with. ( {:a rdf:type :b} is legal OWL-DL, under appropriate constraints, and is an instance of the query under binding of a variable to a legal OWL-DL identifier, so... ) I meant only that if one takes a 'natural' extension of SPARQL to OWL, keeping the basic form of the definitions but replacing simple entailment by OWL-DL entailment, then examples like this turn up. I do not mean to quarrel with what you have done or suggest it should have been done in any other way. The only reason for our discussing this matter at all *in this forum* is because some folk - notably, Bijan and yourself - have argued forcibly that the SPARQL definitions should be couched in a way which generalizes naturally to the OWL case, by replacing 'simply entails' with 'OWL-DL entails' in the definitions. That is what I did. >First of all, I have been sloppy in my statement, since OWL-DL >queries do not exist - we are defining them now here. Now, there is >*no* theoretical nor practical result that even considers queries of >that kind in the DL literature. I do not dispute this. As I said, I was simply applying the proposed SPARQL definitions to OWL-DL (as defined in the OWL specs). If this gets us to an area that has not yet been explored in the research literature, that seems to me to be in fact an extremely good reason for NOT including ANY mention of OWL in the SPARQL documents at all, other than perhaps an informative warning that this is an open problem area unsuitable for standardization at the present. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 cell phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Thursday, 19 January 2006 17:33:46 UTC