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 11:42:44 UTC