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Re: Timeline

From: <herman.ter.horst@philips.com>
Date: Tue, 11 Feb 2003 15:58:15 +0100
To: Jim Hendler <hendler@cs.umd.edu>
Cc: www-webont-wg@w3.org, Jeremy Carroll <jjc@hplb.hpl.hp.com>
Message-ID: <OFB97D6425.60055A71-ON41256CCA.00390D42-C1256CCA.0052682A@diamond.philips.com>

> At 14:35 +0100 2/7/03, herman.ter.horst@philips.com wrote:
> >Jeremy writes:
> >
> >>  It is unclear how many of Herman's review comments on AS&S
> >>  have been addressed.
> >
> >A quick look through the version of 3 February of AS&S indicates
> >that the status of processing this review is still largely
> >as described in my overview at [1].
> >
> >Herman
> >
> >[1] http://lists.w3.org/Archives/Public/www-webont-wg/2003Jan/0426.html
> 
> Herman, [1] seems to contain mostly editorial changes that don't 
> effect our langauge design - am I right in that?  The only specific 
> technical objection I see is one you raise against RDF Core which we 
> cannot resolve.  If you think any of these are TECHNICAL issues that 
> need WG discussion, please let us know.  Otherwise, there is no 
> reason for the editors to deal with them until all the technical 
> issues are dealt with - otherwise we'll never converge.

My review does indeed not have effect on language design.

My review contains a technical objection which was somewhat hidden 
in the overview at [1], and described more fully in the original 
review part (see [2] below).  It deals with the description of
OWL DL (and OWL Lite) as RDF graphs.

It was not until the last weeks of 2002 that a first version 
of this material entered the WebOnt documents, as Section 4.2 of AS & S.
I stated in [2] that the correctness of this material is an issue,
and made suggestions for reorganization.
Jeremy works on an alternative proposal for this material.
I mentioned in the last telecon that the need for such material
is explicitly stated by the (Last Call version of the)
RDF Semantics document:
> Specifications of such syntactically restricted semantic extensions 
> MUST include a specification of their syntactic conditions which are 
> sufficient to enable software to distinguish unambiguously those 
> RDF graphs to which the extended semantic conditions apply. 
(capitalization as in the original)

The WebOnt choice to base OWL syntax on RDF and OWL semantics 
on abstract syntax necessarily leads to the obligation to
prove an RDF characterization of OWL DL/Lite (as just discussed)
and also to prove the RDF characterization of OWL DL entailment 
(given in Section 5 and Appendix A of AS & S).
Although Issue 5.3, Semantic Layering, was formally closed a while ago,
it might be said that it is only completely closed when the Semantics
document is finished, including these proofs.

==

Although I did indeed make editorial comments, my review mainly aimed to 
check and help to ensure that the mathematical details are correct.
The discussions with Peter are not yet completely finished.
Sometimes this indeed involves not only the OWL AS & S document
but also the RDF Semantics document.

> -- 
> Professor James Hendler hendler@cs.umd.edu
> Director, Semantic Web and Agent Technologies      301-405-2696
> Maryland Information and Network Dynamics Lab.     301-405-6707 (Fax)
> Univ of Maryland, College Park, MD 20742           240-731-3822 (Cell)
> http://www.cs.umd.edu/users/hendler

Herman

[2] http://lists.w3.org/Archives/Public/www-webont-wg/2003Jan/0227.html
Received on Tuesday, 11 February 2003 10:00:41 GMT

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