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

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.

Received on Monday, 12 December 2005 09:28:26 UTC