- From: pat hayes <phayes@ai.uwf.edu>
- Date: Wed, 30 Oct 2002 22:40:37 -0600
- To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
- Cc: www-webont-wg@w3.org
>I PROPOSE that OWL augment the characterization of the RDF List vocabulary >so that it serves the needed purpose for OWL. The technical details for >this augmentation can be found in > > http://www-db.research.bell-labs.com/user/pfps/owl/rdfs.html > >I PROPOSE that there be no owl:List, owl:first, owl:rest, or owl:nil. That won't work. The proposed semantics for the RDF list vocabulary is an empty semantics. There will be no restrictions on lists: they can have multiple heads, forking tails, rdf:nil can have countably many rdf:rest properties. All manner of 'impossible' things will be allowed. The resulting structures will bear no semantic or syntactic relationship to Lisp-style lists in the usual sense at all: they will be arbitrary graph structures linked by the list vocabulary names in arbitrary ways. Recursive algorithms will not work on them. In order to use this coherently in OWL we will still need owl:List (a subclass of rdf:List, analogous to owl:Thing a subclass of rdf:Resource) and owl:nil (distinct from rdf:nil, which can be in the domain of rdf:rest and hence cannot be used as an end-of-list marker in OWL), and we will need to essentially axiomatize Sexpressions in OWL. So the OWL list vocabulary will be, at best owl:List rdf:first rdf:rest owl:nil which it seems to me is a bad decision on almost all grounds. Im not even sure if we can use rdf:first and rdf: rest, since other applications might consistently assume that a list can have, say, three rdf:firsts; that would be consistent with the proposed RDF specs. It is a violation of the RDF spec for OWL to impose extra meaning on something in the RDF namespace, so OWL should use its own properties and subproperty them to the RDF list properties. I therefore PROPOSE instead that OWL totally ignore the RDF list vocabulary, which will not have a semantics adequate for OWL purposes, and instead revert to using its own list vocabulary. >I maintain that this sort of augmentation is entirely in keeping the >entirely of the RDF(S) philosophy. It would be if it could be made to work, but I do not believe it can be. Pat PS. I have BCCd this message to the RDF core WG for information purposes. -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes s.pam@ai.uwf.edu for spam
Received on Wednesday, 30 October 2002 23:41:27 UTC