From: Pat Hayes (phayes@ai.uwf.edu)
Date: 12/03/01
>Pat, >At 03:46 PM 11/29/2001, Pat Hayes wrote: >>>Peter, >>> >>>thanks for your answer. >>>I'm still not clear if I could represent an interpretation graph >>>in RDF, given the right vocabulary. >> >>My reply would be: suppose you can. So what? Ie what significance >>would you attribute to the ability to describe such a structure in >>RDF? > >my understanding is, that RDF can serve as a universal data model - thus >representing any structured data. Yes, but representing data, and representing one interpretation of some data, are not the same thing. I understood you to be talking about the latter, not the former. >Thus investments in RDF can be >justified by the reusability of the results. > >If this is true, tools suitable to store and query RDF data can be >used for XML >documents as well, if Peter's interpretation of XML documents is applied. ? How? Just representing one interpretation does not represent all the content of the document. You would need, in the general case, infinitely many such representations (disjoined) to represent the content. > >If RDF is not suitable as a universal data model, I would like to figure out >why not. Well, come come; you are enough of a logician to work that out for yourself, surely. Obviously a simple existential-conjunctive logic with binary relations is not sufficient as a universal data model. > >>Pat >> >>(PS. BTW, it depends on what you mean by 'describe', by the way. If >>you mean, can you make an RDF graph that is isomorphic, then of >>course you can if the interpretation is finite, and not if it is >>not. >Hm, we are talking only about finite amounts of data, right? >>If you mean, can you write some RDF so that SOME interpretation of >>it is isomorphic, the answer is yes, trivially; if you mean, write >>some RDF so that ALL interpretations are isomorphic, the answer is >>no. If you mean, so that all interpretations in some class of >>interpretations are isomorphic, (eg all 'minimal' interpretations >>in some sense), then say what class you have in mind. >My question was if there are computable functions f, fi, with f maps an >XML interpretation to an RDF graph, such that fi o f = id. >Is it the last case? The odd thing to me is to even be in the business of mapping interpretations to graphs. Why would one seek to have a computable mapping from semantics to syntax? 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
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