- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Fri, 5 Oct 2001 16:57:02 -0500
- To: jos.deroo.jd@belgium.agfa.com
- Cc: www-rdf-logic@w3.org
>[...] >> I may simply have not been following the point properly. Coming from >> logic, I have an acute sense of the difference between information >> which is conveyed as part of the very syntax of a language, and that >> conveyed by making assertions in the language. This seems like a very >> sharp and important distinction to me. My understanding of the >> proposal was that the syntactic encoding of, say, integers implicit >> in the notion of literal was to be abandoned and replaced by an >> assertional encoding in RDF triples. That may be a good idea, but it >> does potentially throw away a lot of valuable properties implicit in >> the syntactic typing of literals. However, if this proposal is better >> thought of as one to introduce a more uniform notion of syntactic >> typing for URIs in general, then I'm all for it. Sorry if my >> ignorance is a barrier to communication. > >that is indeed the crucial point! >let me refer to our "tangent point" testcase > http://www.agfa.com/w3c/euler/tpoint.n3 > http://www.agfa.com/w3c/euler/tpoint-facts.n3 >which is making use of "an assertional encoding in RDF triples" >(think about log:implies as an entailment between graphs) >I think this example should make use of some (primitive) >datatypes, but only to a certain extent, because when >the granularity is too big, I don't see straightforward >inferincing capability to have answers to such questions as > http://www.agfa.com/w3c/euler/tpoint-query.n3 >especially while having a given point within the circle >(2 complex solutions) which is later maybe "ruled" out by >the inference engine (using further rules of course). Well, it all depends on what you mean by 'straightforward inferencing' . I would say that the use of log:implies goes beyond RDF inference already, so I see no harm in allowing some inferential extensions that are capable of doing things like treating integers specially, calling out the inference engine to an arithmetic equation-solver, for example. Industrial-strength inference engines often do this kind of thing. I think SNARK has a general-purpose way of defining them and attaching them to the unifier. The Cyc inference engine has about 25 special-purpose callouts for things like partial order embeddings, checking graph matching, temporal interval reasoning and so on. I imagine that useful categories of literal would have appropriate inference subengines definable for them. This does go beyond a basic RDF reasoner, but then literals go beyond basic logic, so that's what you would expect, no? 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 Friday, 5 October 2001 17:57:11 UTC