- From: pat hayes <phayes@ai.uwf.edu>
- Date: Sat, 23 Jun 2001 23:25:44 -0500
- To: Sergey Melnik <melnik@db.stanford.edu>
- Cc: w3c-rdfcore-wg@w3.org
>Brian, > >I'd just like to reiterate some of the arguments for making reification >a built-in feature (possibly as an optional layer): > >- in M&S, reified statements need to have a URI. It looks like they >should be unique, but nobody wants to deal with uniqueness, but still >some sort of URIs need to be assigned, so we end up having to deal with >different URIs denoting the same statement etc. > >- in M&S, we need a specific vocabulary to express/use reification. >Reification could be defined without relying on vocabularies. Im not sure that makes sense. Quotation, or something similar, could be defined without vocabularies, indeed (you just need a quotation syntax), but quotation alone doesn't really give you the full power of reification, since it provides no way to reason about the reified statement: all you can do is to exhibit it, you can't get at its 'parts' without some kind of particular meta-language vocabulary. >- as defined in M&S, reification is extremely verbose and clumsy both in >APIs and in the syntax, Well, the XML syntax for RDF is all extremely verbose and clumsy, so...? >and very few people are using it as suggested. >However, I personally believe it is a useful feature when introduced >correctly and compactly, and it can be easily handled in APIs and >databases as an intrinsic model feature. > >Finally, (s1 p1 (s2 p2 o2)) looks nicer in the abstract syntax... True, but don't get that confused with (s1 p1 '(s2 p2 o2)). (Is the inner triple mentioned or used? Reified or a subexpression?) Pat Hayes > >Sergey > > >Brian McBride wrote: > > > > Hi Graham, > > > > Thanks for this. One question: > > > > Graham Klyne wrote: > > > > > > > > NOTE: "reification" is deliberately called out as a distinct syntax > > > production, so that there is a place to hang the semantics that >distinguish > > > it from any other collection of facts. There is some syntactic ambiguity > > > here that needs to be resolved at some level; e.g. adjusting >the abstract > > > syntax so that rdf:subject, rdf:object, rdf:predicate can >appear *only* in > > > a production for R (and not for A). > > > > In M&S 1.0 the statements of a reification (i.e. the rdf:type, rdf:subject, > > etc ...) are no different from other statements. What difference are > > you considering introducing here? > > > > Brian --------------------------------------------------------------------- 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, 25 June 2001 10:43:43 UTC