- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Mon, 10 Dec 2001 11:13:12 -0600
- To: Dan Connolly <connolly@w3.org>
- Cc: w3c-rdfcore-wg@w3.org
Sorry this reply is delayed. >OK, I blathered on about this requirement in... > > literals must be self-evident > Dan Connolly (Wed, Oct 17 2001) > http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Oct/0338.html > >but recent discussion with Peter S. and Jeremy made me realize >I can reduce this to a real simple entailment test: > >Does dte-blunt.nt entail dte-pointy.nt? > >dte-blunt.nt: > > <http://example/x> <http://example/y> "abc". > >dte-pointy.nt: > > <http://example/x> <http://example/y> "abc". > >i.e. does an RDF document entail itself? >Surely the answer is yes, right? >I suggest that P/P++ do not guarantee this entailment; >they fail to specify that the answer to this >test is "yes". > Well wait a minute. Are those the SAME graph, or two different but isomorphic graphs? Do you mean, does a document entail *itself*, or does it entail any other document with the same lexical form? In the P++ scheme, distinct literal nodes are treated as syntactically distinct entities, so the answer matters. For example, suppose that we were to merge these two graphs. Would the result contain two triples or one? If the answer is one, then they are the same document and this document entails itself (of course). If the answer is two, then they are two distinct but similar documents, and the answer then is, indeed, no in the P++ scheme, since those two different literal occurrences might be typed differently. But this, seems to me, does not violate the guidelines you enunciated in http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Oct/0338.html since there you talk about an interpretation being CHANGED - redefined - by the addition of information. Here, nothing is being changed; if you add datatyping information, you are simply disambiguating the bare literal by adding more information about it, by removing some of its (datatyped) interpretations. This is just like normal RDF inference, right? The only difference is that every occurrence of a bare literal has to be treated as a separate syntactic entity. That gives inference a slightly unusual 'feel' on bare literals, perhaps, but it isn't anything disastrous. There is no nonmonotonicity, if you stick to the rules. 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 Monday, 10 December 2001 12:13:10 UTC