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

From: Ivan Herman <ivan@w3.org>
Date: Sat, 21 Feb 2009 09:13:33 +0100
Message-ID: <499FB7AD.3040200@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>
We seem to have discussed this one to death:-)... anyway, I found the
discussion on the FS useful for me at least!

I have modified the Wiki site with the draft answer. I did add a half
sentence, though, to answer to the question; the last sentence now reads:

[[[
In the example you mentioned, for example, the "_:1" simply represents a
blank node in the RDF graph, and this is indeed the only syntactic mean
to define a blank node.
]]]

See you soon!

Ivan

Ian Horrocks wrote:
> 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
>>
> 

-- 

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 Saturday, 21 February 2009 08:14:07 GMT

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