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Re: Profiles intro

From: Ivan Herman <ivan@w3.org>
Date: Thu, 10 Apr 2008 14:46:42 +0200
Message-ID: <47FE0C32.1050706@w3.org>
To: Bijan Parsia <bparsia@cs.man.ac.uk>
CC: Carsten Lutz <clu@tcs.inf.tu-dresden.de>, OWL Working Group WG <public-owl-wg@w3.org>
Bijan,

let us not start a row here. I may have been a bit harsh in my 
reactions, Carsten hit a nerve:-) I do not think we should go down the 
road of differentiating among profiles on the basis of whether they are 
RDF-ish or not. Ie, can we set this aside and get back to the original 
issue? :-)

Ivan



Bijan Parsia wrote:
> On 10 Apr 2008, at 12:36, Ivan Herman wrote:
> 
>> Hi Carsten,
> [snip]
>> I am trying to find what the _emphasis_ is, and not to be exhaustive! 
>> That is why I used the word 'emphasis'. What would you put in place 
>> instead?
> 
> This is part of the trick, yes? It's hard to be emphatic without 
> suggesting exhaustion.
> 
> [snip]
>> Ouch. That hurts. This is a Semantic Web ontology, so if an ontology 
>> is unrelated to RDF triplets, than what does it have to do with this 
>> group?
> 
> Surely Semantic Web != RDF or even, necessarily, RDF like. For example, 
> consider the homogeneity of RDF syntax (everything is a triple). That's 
> not shared by other web languages (e.g., HTML or SVG, nor is it shared 
> by many  other KR languages. Arguably (though you may disagree) it's an 
> accidental feature of RDF rather than an essential feature. OWL-R is 
> designed, afaik, to be triple oriented.
> 
> Furthermore, I would be surprised if the W3C thought that members had to 
> commit *at all* to the web aspects of OWL in order to be a participant 
> in the group or to advocate features or profiles. Surely, the W3C wants 
> to be responsive to member needs?
> 
>> I do not see why OWL-R would be more RDF-ish than DL Lite or vice versa.
> 
> RDF, in practice, is existential free (this is what we argue about with 
> bnodes). RDF rule implementations tend to skolemize and not infer Bnodes 
> as variables. OWL-R is designed not to have existentials in the head. 
> Thus, it is more RDF-ish.
> 
>> We are talking about data and, possibly, lots of it. Those are 
>> typically  RDF or RDF-able on the Semantic Web.
> 
> But it's not the *Semantic Web* ontology language, it's the *Web* 
> ontology language!
> 
> (Sorry, couldn't resist ;))
> 
>> That DL-Lite may be of interest outside of the Semantic Web may be 
>> true, but is besides the point in this environment...
> 
> Exactly not, I would say.  Intranets and walled gardens are important to 
> HTML. Non semantic web and even non web uses of OWL are in scope. (Dan 
> Connolly often makes this point.) After all, the more contexts OWL is 
> useful, the more likely it'll get good support.
> 
>>>> profiles are defined: DL-Lite, that can be implemented on top of 
>>>> traditional database systems using query rewriting, and OWL-R, that 
>>>> can be implemented using basic rule systems.
>>>> ]]]
>>> True.
>>>> I hope this is at least factually correct. It is interesting to note 
>>>> that on such high level there is no real difference between DL-Lite 
>>>> and OWL-R, and the only way to differentiate them on that level is 
>>>> how they are implemented.
>>> Yes, a main difference between DL-Lite and OWL-R is implementation
>>> techniques. Another one is maybe RDF-ishness.
>>
>> where I strongly disagree.
> 
> Do you disagree that OWL Full is more RDF(S)ish than OWL DL? It seems a 
> relatively harmless observation.
> 
> I do think that DL Lite is generally fairly RDF(S)ish. E.g., when I 
> first saw it I immediately though that it was a nigh-perfect small 
> superset of RDFS. But surely it isn't out of court to point out that 
> it's a bit less triplely, per se?
> 
> [snip]
>> On the other hand, we need names that are suggestive and helpful to 
>> people. Having said that, 'OWL DL' is a meaningless name for those who 
>> do not know what description logic is...
> 
> Not really. I mean, there are plenty of people who just know it as OWL 
> DL as in "y'know, that think pellet implements". Oversuggestion can be 
> dangerous (as I said before).
> 
> Cheers,
> Bijan.
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf


Received on Thursday, 10 April 2008 12:47:54 GMT

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