- From: Jonathan Borden <jborden@mediaone.net>
- Date: Sun, 27 May 2001 14:02:41 -0400
- To: "Graham Klyne" <GK@NineByNine.org>
- Cc: <www-rdf-logic@w3.org>
Graham Klyne wrote: > ... > > And some personal thoughts about your proposed representation: > > I cannot help wondering if it has gone too far in the opposite > direction. In my musings about statements and contexts [1], I > settled on a > quadruple-based structure (different from the CWM structure you > describe), > which (in some interpretations) would treat <id,p,s,o> as a > reification of > a statement '(s p o)' with identifier 'id'. I find that, with additional > RDF properties (and associated semantics), this seems to be capable of > capturing the important aspects of the expression you mention, Right, the (p,s,o,context) quad has been used for decades (e.g. Grasper http://www.ai.sri.com/~grasper/), in your paper as well as TimBL's. >... thus: > > You propose a Statement is represented by the 7-tuple: > <predicate,subject,object, contextURI,id, index, asserted> > > Your 'ContextURI'+'id' serve the same purpose as my id. reserving the > components of a QName structure has some appeal, but I'm not clear if it > needs to be done at this level. Sure. One can similarly debate/discuss whether the predicate,subject,object might be best represented as a QName e.g. <namespace URI, localname> pair. > > Your 'index' is to do with preserving information about lexical > ordering of > statements. I have serious doubts that this has a place in the RDF > r5epresentation: either the ordering is significant in which case it > should be captured in the RDF graph, or it is not. I would like to see another proposal to implement containers, particularly rdf:Seq. I, and numerous others, find the current syntactic contortion of <rdf:li> -> rdf:_1 painful. The entire treatment of containers a mess badly in need of fixing. It turns out that lexical ordering already _has_ a place in RDF, my proposal is an attempt to fix the current problem. > (I note the arguments > that order is "semi-significant", but do not think that these justify > complicating the core RDF structure. Individual applications are free to > preserve additional information as they see fit.) If an individual application is _free to preserve_, this information _should_ be in the abstract syntax, else different applications will use different abstract syntaxes, rendering the RDF well, confusing. > > Your 'asserted' property is captured in my framework by an explicit > property linking the context in which the statement is asserted to the > reified statement. Thus, an asserted statement needs two tuples: one to > describe the statement, and one do describe its assertion. I am > comfortable with the additional tuple required; for some purposes (e.g. > mine!) I feel it is more expressive. Not two extra statements: 5, one to describe assertion and 4 for reification. A single property seems a worthy tradeoff to reduce the number of statements by a factor of 5. -Jonathan
Received on Sunday, 27 May 2001 14:03:51 UTC