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

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Fri, 20 Feb 2009 22:04:47 +0000
Message-Id: <DA6CCC8C-1939-4486-94B7-258A2236B1DA@comlab.ox.ac.uk>
Cc: Michael Schneider <schneid@fzi.de>, W3C OWL Working Group <public-owl-wg@w3.org>
To: Ivan Herman <ivan@w3.org>
I'm pretty sure that his main concern was w.r.t. backwards  
compatibility. I suggest that we simply try the answer below and see  
what he says.

Ian

On 20 Feb 2009, at 19:29, Ivan Herman wrote:

> 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 22:05:25 GMT

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