- From: Dan Connolly <connolly@w3.org>
- Date: 06 May 2003 08:57:48 -0500
- To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
- Cc: Pat Hayes <phayes@ai.uwf.edu>, Dave Beckett <dave.beckett@bristol.ac.uk>, w3c-rdfcore-wg@w3.org
Regarding my action... ACTION 20030425#5 danc figure out the cost to WebOnt of accepting timbl-03 where timbl-03 is short for http://www.w3.org/2001/sw/RDFCore/20030123-issues/#timbl-03 The relevant bit of the OWL spec is: "the ontologies in O, taken together, provide a type for every individual ID;" -- Web Ontology Language (OWL) Abstract Syntax and Semantics Section 4. Mapping to RDF Graphs http://www.w3.org/TR/owl-semantics/mapping.html#4.1 http://www.w3.org/TR/2003/WD-owl-semantics-20030331/mapping.html#4.1 And without the rdf:List triples, the collection syntax doesn't meet that constraint. Jeremy and Peter discussed the cost of relaxing that constraint, and it seems, to me, to be considerable: the details of the mapping of owl-dl-abstract-syntax to RDF graphs are somewhat subtle and impact many parts of the S&AS spec, especially the semantic layering bits. http://www.w3.org/2001/sw/WebOnt/webont-issues.html#I5.3-Semantic-Layering Meanwhile, note that the exact details of the mapping to RDF graphs were not decided by consensus; there is an outstanding objection (from JJC/HP). http://www.w3.org/2001/sw/WebOnt/webont-issues.html#I5.26-OWLDLSyntax In sum, the rdf:List triples do serve a purpose in the graph syntax of OWL; a purpose which rdfs:domain/rdfs:range won't help with. On Tue, 2003-05-06 at 03:24, Jeremy Carroll wrote: > > I personally agree > > with Tim that these (type List) triples are redundant, and I would > > bet that the OWL stuff, even if it does need them, could be trivially > > rewritten so that it did not. I was hoping that we could get back to > > Peter and find out whether he thought the problem was serious. > > Peter punts the problem back to me - since I am the most recent person on > record as arguing for type triples in general (in OWL DL). > > Here are my thoughts: > > 1: this is merely aesthetic either way > People who don't/do want the type triples can have what they want simply > by not using the rdf:parseType="Collection" syntax (whichever way we > decide). > > 2: the triples *are* redundant > It is easy to automatically add them; or for that matter, automatically > remove them. > > 3: the construct was added for OWL, and so the aesthetic judgement as to > whether they should be there or not in the convenience > rdf:parseType="Collection" syntax, should be made by WebOnt. > > 4: Given that in OWL DL and OWL Lite many type triples are needed, it is, in > my opinion, more aesthetic, to have these type triples also for Lists. The > need for type triples is principally to distinguish the various types of > user defined in Property in OWL Lite and OWL DL. > > Jeremy -- Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 6 May 2003 10:13:09 UTC