Re: [Use Case] ETRI-UC1: Filling the holes of OWL ontology

You can't do "uncle" in OWL-DL in the sense you want, I think Jim's point 
was that you can define *something* that eliminates some unintended 
models.  Unless one of the mindlab guys have found another clever b-node 
based trick.

-Chris

Dr. Christopher A. Welty, Knowledge Structures Group
IBM Watson Research Center, 19 Skyline Dr., Hawthorne, NY  10532
Voice: +1 914.784.7055,  IBM T/L: 863.7055, Fax: +1 914.784.7455
Email: welty@watson.ibm.com
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Bill Andersen <andersen@ontologyworks.com> 
Sent by: public-rif-wg-request@w3.org
12/12/2005 06:42 AM

To
Enrico Franconi <franconi@inf.unibz.it>
cc
Jim Hendler <hendler@cs.umd.edu>, Minsu Jang <minsu@etri.re.kr>, W3C RIF 
WG <public-rif-wg@w3.org>
Subject
Re: [Use Case] ETRI-UC1: Filling the holes of OWL ontology







Hi all,

Enrico, thanks for clarifying the issue on tree-shaped models.

Jim, could you provide a reference (or perhaps an example) to how one 
does "uncle" in OWL-DL?

Thanks,

                 .bill

On Dec 12, 2005, at 04:27 , Enrico Franconi wrote:

>
> On 11 Dec 2005, at 18:39, Jim Hendler wrote:
>> At 19:57 +0900 12/11/05, Minsu Jang wrote:
>>> When building ontologies using OWL, we usually come up with such 
>>> relations or classes that are difficult or impossible to express 
>>> in OWL, which creates vocabulary holes in the ontologies. The 
>>> most representative hole is the set of relations that can be 
>>> defined by chained properties[1][2]. For example, with OWL alone, 
>>> you cannot describe "uncle" relation, which is the composition of 
>>> "father" and "brother" relation, into the family ontology. With 
>>> rules, it's trivial to describe the relations defined by chained 
>>> properties. As such, RIF will be an essential semantic web 
>>> language that complements and extends OWL.
>>
>> Actually, let us be clear here - it is easy to come up with a 
>> definition of uncle in OWL and one can even rule out inconsistent 
>> cases using a DL reasoner (for example,  I could discover it was 
>> inconsistent for Bob to be in a "no siblings" class if I knew Bob 
>> was in the uncle class).  What each of the various approaches can 
>> do with "uncle" is actually quite complicated, gets into issues of 
>> grounded literals and other such things (i.e. many rule systems 
>> can't find all uncles because you may need unsafe reasoning to 
>> remain decidable) -- I don't object to the thrust of the use case 
>> about doing things OWL cannot, but this canard about "not doing 
>> uncle" is a misunderstanding of something Ian Horrocks said in 
>> some email to the Web Ontology Working Group (i.e. it's been taken 
>> out of context)  and needs to be much more carefully elucidated if 
>> you want to use it in a use case...
>
> I guess that a proper use case could be built on the fact that 
> nominal-free OWL-DL does not have the ability to describe non-tree 
> models: you need to extend the language, e.g., with rules, to be 
> able to *properly* describe cyclic graph shaped models.
>
> cheers
> --e.
>
>

Bill Andersen (andersen@ontologyworks.com)
Chief Scientist
Ontology Works, Inc. (www.ontologyworks.com)
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Odenton, MD 21113
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Received on Monday, 12 December 2005 18:58:52 UTC