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Re: Fragments - specific proposal

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Mon, 10 Dec 2007 09:19:17 -0500
Message-Id: <AADCF74B-CF42-412F-8189-B33E6FB4ED4C@cs.rpi.edu>
Cc: OWL Working Group WG <public-owl-wg@w3.org>
To: Carsten Lutz <clu@tcs.inf.tu-dresden.de>
Forgive me - but the definition I see shows a grammar of the language  
and statements like

The language EL++, as presented here, is not a fragment of OWL DL,  
since it provides complex inclusion axioms on Object Properties. The  
fragment of EL++ that does not provide these axioms is indeed a  
fragment of OWL DL. EL++, as presented in this document, is slightly  
more restrictive than the language defined in [EL++]; in particular,  
this document enforces the regularity condition on complex property  
inclusion axioms required in OWL 1.1. With this restriction, EL++ is  
a fragment of OWL 1.1.

it does not seem to include the instance related terms (sameAs and  
differentFrom) which are heavily used in the existant ontologies, and  
the syntax is not defined in terms of the actual language terms,  
would be like saying "Java allows loops" without specifying how (i.e.  
the actual OWL vocabulary used).

On Dec 10, 2007, at 8:08 AM, Carsten Lutz wrote:

> On Sat, 8 Dec 2007, Jim Hendler wrote:
>>
>> so make a counter proposal - what do you want in it?  I already  
>> said that if we could express EL++ in a way that was easily  
>> understood I'd be willing to explore that being OWL Light
>
> I am not sure I understand what you mean. In fact, your wiki page on
> RDFS 3.0 has almost exactly the same kind and amount of information
> that Bernardo's "tractable fragments" doc has on EL++. Additionally,
> there are pointers to the literature. Could you please explain what
> kind of information would allow you to understand EL++ better? I am
> happy to provide more information (and I *will* start an EL++ wiki
> page, good idea), but frankly I am not sure at all what you would like
> to have.
>
>> - my proposal is that we DESIGN the fragment, not necessarily pick  
>> an existing one.
>
> Yes and no. Fragments like EL++ and DL-Lite received years (and a lot
> of manpower) of research. I don't think that we can do this in a  
> standardization group for completely new fragments---though individual
> members may of course decide to inverst the time and efforts to do it.
> On the other hand, this doesn't mean that we have to use fragments as
> is. We can make minor adjustments to make them more suitable for us,
> as long as we understand the ramifications.
>
>>  But if you want something else, I think it is incumbent on you to  
>> make clear what your motivations are -- I did so on the fragments  
>> page on the WIki,
>
> I did so in several previous mails?!?
>
>> and continue to invite you and anyone else interested to outline  
>> other proposals -- it's easy to argue against things, let us know  
>> what you are arguing for and why.
>
> Again: did that already in previous mails. But will additionally open
> a wiki page.
>
>> Carsten - I think you and I use "widely" at different orders of  
>> magnitude, but that said, if EL++ could be defined cleanly in  
>> terms that non-logicians could understand
>
> I had believed that the functional syntax used in the OWL docs is what
> non-logicians can understand.  It is in this syntax that Bernardo
> describes EL++. It makes me worried if this syntax is considered not
> understandable since this is what is used in the main documents of
> this working group... What would you prefer?
>
> greetings,
> 		Carsten
>
> --
> *      Carsten Lutz, Institut f"ur Theoretische Informatik, TU  
> Dresden       *
> *     Office phone:++49 351 46339171   mailto:lutz@tcs.inf.tu- 
> dresden.de     *

"If we knew what we were doing, it wouldn't be called research, would  
it?." - Albert Einstein

Prof James Hendler				http://www.cs.rpi.edu/~hendler
Tetherless World Constellation Chair
Computer Science Dept
Rensselaer Polytechnic Institute, Troy NY 12180
Received on Monday, 10 December 2007 14:19:35 GMT

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