- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Tue, 24 Aug 2004 18:42:53 +0100
- To: Dan Connolly <connolly@w3.org>, RDF Data Access Working Group <public-rdf-dawg@w3.org>
-------- Original Message -------- > From: Dan Connolly <> > Date: 24 August 2004 17:58 > > I see some nice work on the core terms in the spec in > sections 2.2 and 2.3 > http://www.w3.org/2001/sw/DataAccess/rq23/#GraphPatterns > > I think getting those terms and definitions established > will speed things up considerably. And any help with defintions will be gratefully received. > > Some reaction to $Revision: 1.39 $ of $Date: 2004/08/24 13:35:32 $ > > > let V be the set of variables > > let B be the set of bNodes > > I consider bNodes to be variables, so I'd rather: > > let V be the set of universal variables > let B be the set of existential variables > > since RDF mt "effectively treats all blank nodes as having the same > meaning as existentially quantified variables in the RDF graph in which > they occur" Good point. bNodes are variables over individuals in the domain of discourse. query variables are variables over graph labels/terms. I avoid writing this into the doc as it is confusing. May be it has to go in. It also means, from the query point of view, bNodes are values/constants just like everything else in the RDF graph (constant to the query - not the RDF). > > > > let A be U union L union V union B > > those are traditionally called terms > http://www.earlham.edu/~peters/courses/logsys/glossary.htm#t > so I'd use T there. Some word to cover that would be good - I didn't find one in RDF Concepts but I may have missed it. Term is fine - using "T" is a bit confusing as "triple" comes up a lot so even just swapping T to be term and something else for Triple Pattern isn't going to be clear. There isn't much use of 'term' after this definition so can we use a different-to-tradition symbol here? > > > Now we have a conflict with tradition here... > > > let L be the set of all literals > > let T be the set of triple patterns := A x A x A > > Traditionally, a literal is something like P(x)... > "These formulas are basically sets of clauses each of which is a > disjunction of literals." > -- http://mathworld.wolfram.com/ResolutionPrinciple.html > > Our "triple patterns" function much like literals. Hmm... Sorry - you lost me a bit. It is supposed to be literal as takne from RDF concepts/MT. Would making it "RDF Literals" help? It maybe the levels thing again - variables over different spaces. (I notice cofusion between the T as set of triple patterns the text saying "T is a ground triple"). > > > I don't think I can parse the "Definition: Binding" section. I'll try to rework it. Any suggested text? Either the formal part or explanatory notes. > > I'm inclinded to break out my larch tools to review this > stuff. > http://www.w3.org/XML/9711theory/ > http://www.w3.org/XML/9711theory/RDFAbSyn.lsl That would be great. Warning: the definitions become less solid as you go thought the doc - I have tried to outline the direction (in text) when I haven't tried to give formal, solid definitions. Andy > > > > -- > Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 24 August 2004 17:43:38 UTC