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Re: draft response for LC comment 32 CO1

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 24 Feb 2009 09:43:40 -0500 (EST)
Message-Id: <20090224.094340.78002396.pfps@research.bell-labs.com>
To: alanruttenberg@gmail.com
Cc: ivan@w3.org, public-owl-wg@w3.org
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 Tuesday, 24 February 2009 14:43:58 GMT

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