- From: Alan Ruttenberg <alanruttenberg@gmail.com>
- Date: Mon, 23 Feb 2009 01:01:07 -0500
- To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
- Cc: ivan@w3.org, public-owl-wg@w3.org
While I think the general answer to Chime's comment is clear, I think we would do well to add a couple of specific examples that demonstrate a problem that someone might realistically run in to (ideally constructed after a conversation with someone like Chime) to the profiles document, and mention in the response that we intend to do so. -Alan On Fri, Feb 20, 2009 at 5:01 AM, Peter F. Patel-Schneider <pfps@research.bell-labs.com> wrote: > From: Ivan Herman <ivan@w3.org> > Subject: Re: draft response for LC comment 32 CO1 > Date: Fri, 20 Feb 2009 09:33:06 +0100 > >> Well... although what you say is technically true, I would not find it >> unreasonable if some characteristic _examples_ would be added to the >> profile document for both cases that Chime refers to. This tough >> rebuttal is a little bit to brisk for my taste, and we should have some >> more explanation in our documents in my view. (Whether this is in the >> profile or somewhere else like the primer is of course a different issue!) >> >> I just came up with some things that we could add: >> >> - For his first comment, we could, eg, refer to the fact that arbitrary >> RDF graphs may include statements on the otherwise reserved vocabulary >> with all kinds of funny consequences, or that they would allow defining >> functional datatype properties whose consequences are a bit unpredictable. > > Fine. I'll put in something like: > > Arbitrary RDF graphs can include constructs that have surprising > consequences. The reasons for these are many and varied, including > effects on the "syntax" of OWL 2. Because there are so many ways in > which the rules could incorrect, the working group has decided not to > exactly characterize how the incorrectness arises, but instead has > included a mention that arbitrary RDF graphs can affect the > underpinnings of OWL, as follows: > > For ontologies satisfying the syntactic constraints described in > Section 4.2, a suitable rule-based implementation will have desirable > computational properties; for example, it can return all and only the > correct answers to certain kinds of query (see Section 4.3 and > [Conformance]). Such an implementation can also be used with arbitrary > RDF graphs. In this case, however, these properties no longer hold — > in particular, it is no longer possible to guarantee that all correct > answers can be returned*, for example if the RDF graph uses the > built-in vocabulary in unusual ways.* > >> - An example of the (missing) consequences due to the missing RDF(S) >> axiomatic triples and some of the entailement rules is that >> >> rdf:_i rdf:type rdfs:ContainerMembershipProperty . (axiomatic rule) >> meaning that >> rdf:_i rdfs:subPropertyOf rdfs:member . (rdfs12 entailement rule) >> >> If these were around, an OWL RL user could handle container membership >> more easily with those rules. > > I don't know whether *these* triples and rules provide an example of the > missing inferences. Perhaps Boris can comment or provide an example. > >> Ivan > > peter > > >> Peter F. Patel-Schneider wrote: >>> [Draft Response for LC Comment 32:] CO1 >>> >>> Dear Chimezie, >>> >>> Thank you for your message >>> http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0039.html >>> on the OWL 2 Web Ontology Language last call drafts. >>> >>> Arbitrary RDF graphs can include constructs that have surprising >>> consequences. The reasons for these are many and varied, including >>> effects on the "syntax" of OWL 2. Because there are so many ways in >>> which the rules could incorrect, the working group has decided not to be >>> more explicit in the introduction to OWL 2 RL. >>> >>> There are an infinite number of RDFS axiomatic triples, so including >>> them all in the OWL 2 RL rules does not directly lead to an effective >>> rule implementation. There are some RDFS rules that produce >>> consequences that are not relevant to the conclusions guaranteed by >>> Theorem PR1. Listing all the "deficiencies" is not particularly easy, >>> and would probably only confuse the issue. The working group has >>> therefore decided not to be more explicit in the preamble to Theorem >>> PR1. >>> >>> Please acknowledge receipt of this email to >>> <mailto:public-owl-comments@w3.org> (replying to this email should >>> suffice). In your acknowledgment please let us know whether or not you >>> are satisfied with the working group's response to your comment. >>> >>> Regards, >>> Peter F. Patel-Schneider >>> on behalf of the W3C OWL Working Group >>> >>> No trees are known to have been harmed in the preparation of this >>> response. >>> >> >> -- >> >> Ivan Herman, W3C Semantic Web Activity Lead >> Home: http://www.w3.org/People/Ivan/ >> mobile: +31-641044153 >> PGP Key: http://www.ivan-herman.net/pgpkey.html >> FOAF: http://www.ivan-herman.net/foaf.rdf >
Received on Monday, 23 February 2009 06:01:44 UTC