- From: Dan Brickley <danbri@w3.org>
- Date: Mon, 3 Sep 2001 09:03:09 -0400 (EDT)
- To: Art Barstow <barstow@w3.org>
- cc: Aaron Swartz <aswartz@upclink.com>, Dave Beckett <dave.beckett@bristol.ac.uk>, <w3c-rdfcore-wg@w3.org>
On Mon, 3 Sep 2001, Art Barstow wrote: > On Sun, Sep 02, 2001 at 01:36:42AM -0500, Aaron Swartz wrote: > > On Wednesday, August 29, 2001, at 09:27 AM, Dave Beckett wrote: > > > > >> while at next telecon agenda items, > > >> what about the N-triples/MT related questions > > >> 1. predicate ::= uriref versus predicate ::= uriref | namedNode? > > > > > > Does RDF allow, let's call it, non-URI-ref for predicates? > > > I don't think so, at present. In the graph model in the original > > > M&S, predicates are arrows with URIs, they are never empty circles. > > > > Well maybe it's an arrow without a URI. > > > I like the idea of allowing predicates to be princeNodes > because it would eliminate special casing predicates (and simplify > N-Triples a little). However, I agree with Dave's position (although > M&S is not explicit on this) and thus have written some apps that > assume predicates will be URI-refs and not princeNodes. > > > I think that princeNodes should be allowed in the predicate > > slot... they're rather useful. > > Would you please give an example where this would be useful? Representing partial knowledge: for example, one might know that persons A and B were related biologically, without knowing whether that was brother/sister/father etc. Being able to represent claims about a relationship that holds between A and B (without URI-naming that relation) could be useful. You could say, for example, that there is a relationship that holds between A and B, and that the relationship was of rdf:type misc:BiologicalRelativeRelation. Where misc:brother, misc:sister etc were members of that class. Sorry for the cheeseball example, I'm in a rush. Another more general example could probably be composed that used WebOnt / DAML+OIL classes such as daml:UniqueProperty. Also for the record, none of my code has any problem with un-named relations, although I've assumed there was no way to serialize this in RDF/XML 1.0. Dan
Received on Monday, 3 September 2001 09:03:13 UTC