W3C home > Mailing lists > Public > www-webont-wg@w3.org > June 2003

Re: Proposed Reply to Martin Merry -- New attempt

From: Dan Connolly <connolly@w3.org>
Date: 16 Jun 2003 11:50:39 -0500
To: Jim Hendler <hendler@cs.umd.edu>
Cc: webont <www-webont-wg@w3.org>
Message-Id: <1055782238.27167.173.camel@dirk.dm93.org>

This seems to be responsive to the comment[9May]
and consistent with WG proceedings; the WG
decided [15May] to drop "Complete OWL DL Consistency Checker"
and the remaining changes are editorial
and largely consistent with advice from the WG
to the editor.

Please do send it, Jim.

[9May]
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0046.html
[15May]
http://lists.w3.org/Archives/Public/www-webont-wg/2003May/0271.html

On Mon, 2003-06-16 at 09:48, Jim Hendler wrote:
> Dear Mr. Merry-
>  Thanks much for your comments.  They have caused us a lot of
> discussion and we have spent a lot of time working out how we could
> set the expectations better, as to the differences between OWL FUll
> and OWL DL. 
> 
> First, we have dropped the discussion of a "Complete OWL DL
> Consistency Checker" from the Test document.  We believe this is
> consistent with your request 
> 
> Second, in the overview we say
> 
> "Owl Lite also has a lower formal complexity than OWL DL, see
> <reference section 8.3> for further details."
> 
> Section 8.3 says:
> 
> The idea behind the OWL Lite expressivity limitations is that they
> provide a minimal useful subset of language features, that are
> relatively straightforward for tool developers to support. The
> language constructs of OWL Lite provide the basics for subclass
> hierarchy construction: subclasses, value and cardinality
> restrictions. In addition, OWL Lite allows properties to be made
> optional or required (using the cardinality features). The limitations
> on OWL Lite place it in a lower complexity class than OWL DL. This can
> have a positive impact on the efficiency of complete reasoners for OWL
> Lite.
> 
> 
> Section 8.2 (On OWL DL) now reads
> 
> These constraints of OWL DL may seem like an arbitrary set, but in
> fact they are not. The constraints are based on work in the area of
> reasoners for Description Logic, which require these restrictions to
> provide the ontology builder or user with reasoning support. In
> particular, the OWL DL restrictions allow the maximal subset of OWL
> Full against which current research can assure that a decidable
> reasoning procedure can exist for an OWL reasoner.
> 
> 
> We believe these changes help set the expectations more correctly as
> you requested.
> 
> You also raised an issue as to whether we should remove features from
> the current OWL DL.  The issue you raised is that with both
> owl:inverseOf and owl:oneOf (and/or hasValue) in the language, the
> complexity class of OWL DL is higher.  This is true.  On the other
> hand, you state that
> 
> At 3:18 PM +0100 5/9/03, Merry, Martin wrote:
> The theoretical results for the decidability of OWL DL are interesting
> but
> not particularly helpful. OWL Lite is justified by practical results
> in DL
> systems (primarily from Ian Horrocks). There is no such practical
> experience
> for the OWL DL subset.  We would like to see such practical experience
> before OWL exits candidate recommendation.
> 
>  The WG has been made aware of implementations of OWL DL that include
> both inverseOf and oneOf and which seem to be performing well in
> practice.  The working group will definitely consider their status and
> usability before deciding on our schedule with respect to Candidate
> Recommendation and Proposed Recommendation.
> 
> Thank you for your comments, please let us know if our response is
> acceptable and we can close this comment.
> 
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
office: tel:+1-617-395-0241 (new VoIP phone Mar 2003)
mobile: tel:+1-816-616-6576
mobile: mailto:connolly+pager@w3.org
Received on Monday, 16 June 2003 12:50:12 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:58:01 GMT