- From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
- Date: Mon, 2 Mar 2009 19:15:14 +0000
- To: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Cc: alanruttenberg@gmail.com, ivan@w3.org, public-owl-wg@w3.org
I agree. We shouldn't attempt to turn the spec into a general exposition that tries to explain everything to everyone -- that way lies madness (and an *even longer* spec). I think that the current response is good enough. Ian On 24 Feb 2009, at 14:43, Peter F. Patel-Schneider wrote: > I worry about diluting the sections of the Profiles document with all > this extra stuff. > > peter > > > From: Alan Ruttenberg <alanruttenberg@gmail.com> > Subject: Re: draft response for LC comment 32 CO1 > Date: Mon, 23 Feb 2009 01:01:07 -0500 > >> 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, 2 March 2009 19:15:56 UTC