- From: pat hayes <phayes@ai.uwf.edu>
- Date: Tue, 3 Jul 2001 10:22:27 -0700
- To: Dan Connolly <connolly@w3.org>
- Cc: w3c-rdfcore-wg@w3.org
>Frank Manola wrote: > > Dan Connolly wrote: >[...] > > > [[[ > > > 4. A person is between a rock and a hard place. > > > [...] > > > > > > Following is the KIF representation: > > > > > > (exists ((?x person) (?y rock) (?z place) (?w hard)) > > > (and (betw ?y ?z ?x) (attr ?z ?w))) > > > ]]] > > > > > > -- Conceptual Graph Examples > > > http://www.bestweb.net/~sowa/cg/cgexampw.htm#Ex_4 > > > Thu, 22 Mar 2001 01:45:12 GMT > > > linked from http://www.bestweb.net/~sowa/cg/ > > > linked from http://www.w3.org/DesignIssues/CG#[2] > > > > Yes, that was the interpretation I'd been assuming as well (see my > > message > > http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Jun/0326.html) > >Ah... good... then we're agreed, on the essential point. > >[...] > > > So I don't understand how queries come into > > this. > >Then never mind; somebody was convinced by the bookseller >scenario about the need for existentials in RDF, so I thought >I'd try it here. But I don't need the WG to agree with >the bookseller/query scenario; only with the interpretation >of triples as (exists (?a1 ?a2 ...) (and (p1 s1 ?a1) ...) ). Fine. But then I return to my claim that existentials (at top level in assertions) convey exactly the same information as their skolemisation. It isnt technicaly correct to say that they entail or are equivalent to their skolem form (they arent since they use different vocabularies), but they are what might be called *effectively* equivalent, in that anything that can be inferred from one, that doesnt use the Skolem name, can be inferred from the other. In the bookseller example, if you tell the bookseller the skolem form, then he does indeed know something that he wouldnt know if you told him the existential: he knows that you call the book that you want something like "gen4327". But that isnt of much use to him, since he doesn't know anything about gen4327 that he couldnt have inferred from the existential. 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 Tuesday, 3 July 2001 13:25:22 UTC