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Re: 3rd Draft response to LC comment 30 (FH4)

From: Ivan Herman <ivan@w3.org>
Date: Fri, 20 Feb 2009 20:29:57 +0100
Message-ID: <499F04B5.5070101@w3.org>
To: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
CC: Michael Schneider <schneid@fzi.de>, W3C OWL Working Group <public-owl-wg@w3.org>
Hm, you made me uncertain:-( Re-reading his comments again I wonder 
whether his question is not about AS but whether it is possible, in the 
FS, to define anonymous nodes _without_ explicit naming. In which case 
the answer should be a 'no'...

Ivan

Ian Horrocks wrote:
> It wasn't obvious to me that Frank was concerned with the AS. When he 
> said that "it's not clear from the doc. whether the OWL1 syntax is still 
> allowed", I imagined that he was really concerned about the RDF syntax 
> and the expressivity of the language. As I said in my email, the AS has 
> changed in many ways, and it seemed odd that Frank would single out this 
> one.
> 
> Anyway, I don't suppose that it would hurt to put back the paragraph on 
> AS, but I suggest putting it after the one about backwards compatibility 
> of the RDF. The result would be:
> 
> 
> Dear Frank,
> 
> Thank you for your comment
> 
> <http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0037.html>
> on the OWL 2 Web Ontology Language last call drafts.
> 
> We also note the 'addendum' to your original comment in
> 
> <http://lists.w3.org/Archives/Public/public-owl-comments/2009Feb/0014.html>
> 
> And we thank you for helping us avoiding further confusion on this issue.
> 
> It is important to note that nothing changed on the RDF side, and that
> the treatment of anonymous individuals in OWL 2 is fully backwards
> compatible with that in OWL 1. Even on the structural syntax side, there
> is no change in expressive power, but we restructured the syntax to be
> in closer correspondence with RDF graphs to make it clearer that
> anonymous individuals are in direct correspondence with blank nodes. In
> the example you mentioned, for example, the "_:1" simply represents a
> blank node in the RDF graph.
> 
> Concerning the usability of AS in OWL 2: if used as an exchange syntax 
> then, of course, OWL 1 ontologies written in AS may be input to OWL 2 
> tools and remain valid ontologies. But we must emphasize that this is an 
> issue of the tool providers: the only _required_ exchange syntax for OWL 
> 2 ontologies being RDF/XML, it is up to the tools to decide whether they 
> would accept ontologies serialized in AS (or in FS, for that matter).
> 
> We agree this isn't made very clear in the documents, and we will try to
> improve the presentation. For example, we plan to add some explanatory
> text into the New Features and Rationale document on the change of syntax.
> 
> We hope this answers your concerns on this particular issue.
> 
> 
> 
> 
> 
> On 20 Feb 2009, at 12:10, Ivan Herman wrote:
> 
>> Ian,
>>
>> I do not mind using this text, but Frank explicitly asked whether AS is
>> still usable. Why did you leave that part out?
>>
>> Ivan
>>
>> P.S. As an aside, although the text on FS/FOL came from an earlier
>> version of the draft, as written by Bijan, I must admit that this
>> argument seemed to be valid to me. The only way I can explain myself the
>> order of the various arguments and parameters in the language is when I
>> look at the way the same formulae would be written in FOL. But that may
>> be only me, I do not mind taking that out...
>>
>> Ian Horrocks wrote:
>>> Another issue with the proposed response is that I don't think it
>>> clearly answers Frank's main concern (as I understand it), which is
>>> backwards compatibility of the RDF syntax. I also wonder why you talk
>>> about the FS being closer to FOL syntax -- I don't recall this being a
>>> motivation and I doubt that it is relevant to Frank or to  (m)any other
>>> people. Finally, w.r.t. the structural syntax, this has been changed in
>>> *many* respects, so I doubt that compatibility of the structural syntax
>>> is particularly relevant here.
>>>
>>> I therefore suggest the following response:
>>>
>>>
>>> Dear Frank,
>>>
>>> Thank you for your comment
>>>
>>> <http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0037.html> 
>>>
>>> on the OWL 2 Web Ontology Language last call drafts.
>>>
>>> We also note the 'addendum' to your original comment in
>>>
>>> <http://lists.w3.org/Archives/Public/public-owl-comments/2009Feb/0014.html> 
>>>
>>>
>>> And we thank you for helping us avoiding further confusion on this 
>>> issue.
>>>
>>> It is important to note that nothing changed on the RDF side, and that
>>> the treatment of anonymous individuals in OWL 2 is fully backwards
>>> compatible with that in OWL 1. Even on the structural syntax side, there
>>> is no change in expressive power, but we restructured the syntax to be
>>> in closer correspondence with RDF graphs to make it clearer that
>>> anonymous individuals are in direct correspondence with blank nodes. In
>>> the example you mentioned, for example, the "_:1" simply represents a
>>> blank node in the RDF graph.
>>>
>>> We agree this isn't made very clear in the documents, and we will try to
>>> improve the presentation. For example, we plan to add some explanatory
>>> text into the New Features and Rationale document on the change of 
>>> syntax.
>>>
>>> We hope this answers your concerns on this particular issue.
>>>
>>>
>>>
>>>
>>>
>>> On 20 Feb 2009, at 11:08, Michael Schneider wrote:
>>>
>>>> Ivan wrote:
>>>>
>>>>> For example, one can refer to anonymous/blank nodes from
>>>>> more than one place, hence a larger class of RDF graphs can be 
>>>>> expressed
>>>>> in FS.
>>>>
>>>> I would like to see an example for something that can now be written
>>>> in the Functional Syntax, for which there was no corresponding way to
>>>> express it in the old Abstract Syntax. The global syntactic
>>>> restrictions in Section 11.2 of the Structural Spec are pretty
>>>> restrictive, AFAICT.
>>>>
>>>> Michael
>>>>
>>>> -- 
>>>> Dipl.-Inform. Michael Schneider
>>>> Research Scientist, Dept. Information Process Engineering (IPE)
>>>> Tel  : +49-721-9654-726
>>>> Fax  : +49-721-9654-727
>>>> Email: schneid@fzi.de
>>>> WWW  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555
>>>>
>>>> ============================================================================== 
>>>>
>>>>
>>>>
>>>> FZI Forschungszentrum Informatik an der Universität Karlsruhe
>>>> Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
>>>> Tel.: +49-721-9654-0, Fax: +49-721-9654-959
>>>> Stiftung des bürgerlichen Rechts
>>>> Stiftung Az: 14-0563.1 Regierungspräsidium Karlsruhe
>>>> Vorstand: Prof. Dr.-Ing. Rüdiger Dillmann, Dipl. Wi.-Ing. Michael Flor,
>>>> Prof. Dr. rer. nat. Dr. h.c. Wolffried Stucky, Prof. Dr. rer. nat.
>>>> Rudi Studer
>>>> Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
>>>>
>>>> ============================================================================== 
>>>>
>>>>
>>>>
>>>
>>
>> -- 
>>
>> 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
>>
> 

-- 

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 Friday, 20 February 2009 19:31:31 GMT

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