W3C home > Mailing lists > Public > public-owl-wg@w3.org > February 2009

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

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Fri, 20 Feb 2009 12:56:55 +0000
Message-Id: <B8B996C6-9B59-4FA8-AA19-2365546A4EEF@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>
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
>
Received on Friday, 20 February 2009 12:57:47 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Friday, 20 February 2009 12:57:47 GMT