- From: Michael Sintek <sintek@dfki.uni-kl.de>
- Date: Tue, 10 Jan 2006 16:48:30 +0100
- To: public-rif-wg@w3.org
Christopher Welty wrote: > public-rif-wg-request@w3.org wrote on 01/04/2006 02:35:50 PM: > >>Jos de Bruijn wrote: >> >>>On Tue, 2006-01-03 at 18:21 +0000, Dave Reynolds wrote: >>> >>>>Michael Sintek wrote: >> >>... >> >>>>I agree that RDF compatibility requires support for quantification > > over RDF > >>>>properties. Whether this translates into a requirement for a > > higher-order > >>>>syntax for the rule language or into a requirement that the RDF > > mapping > >>>>should use some more straightforward "triple(s,p,o)" convention is a >>>>separate decision. >>> >>> >>>I'm not sure whether support for quantification over RDF properties is >>>required, but I can imagine it could be. >> >>The query <s,?p,o> was only one example where higher order would be >>needed for the "straightforward" mapping. > > > Correction: This is not higher order, though it appears so. I made this > mistake myself many times. That many rule systems do not support it is a > seperate matter (and one we shall strive to address). > > >>The same problem arises for >>queries of the form <s,rdf:type,?c> (i.e., asking for all classes >>of a given instance). If you map triples of the form >><s,rdf:type,c> to c(s), you again need higher order. > > > Again, you need to do something, yes. But it is not a-priori higher > order. I guess we need a clarifying entry in our glossary on higher-orderness and esp. the differences between syntactic and semantic higher-orderness, the relationship of syntactic h-o and meta-modeling, etc. I created the repsective glossary page (still empty!): http://www.w3.org/2005/rules/wg/wiki/Higher-Orderness Feel free to fill it with meat :-) Michael -- Michael Sintek -- DFKI GmbH, Kaiserslautern http://www.michael-sintek.de -- sintek@dfki.uni-kl.de phone: +49 631 205-3460 -- fax: +49 631 205-4910
Received on Tuesday, 10 January 2006 15:48:39 UTC