Re: facts about web ontology languages

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On 11 Dec 2004, at 17:25, Denny Vrandecic wrote:

>
> Hi,
> just some quick notes. Disclaimer: that's the answers as I understand  
> it right now, I may be wrong. And it's weekend, so my brain is running  
> on half voltage on this, and I've just seen the special edition of  
> LOTR:RotK, so be careful with the answers ;)

Ditto :-)

>> Is it right that only OWL full and RDF/s are not decidable, because  
>> they
>> do not seperate between concepts and instances?
>
> OWL Full and RDFS are not decidable, and yes, this is a reason.
> RDF itself is just a data model, and thus the question does not apply.

This is second hand (via Jeremy Carroll), but I understand Herman ter  
Horst presented a paper [1] showing that RDF and RDFS are decidable,  
and further that they are decidable in polynomial time (which is  
cheaper than DLs). I believe this also holds for RDFS + some bits of  
OWL (fp, ifp, inv, sameAs ? i.e. not the restrictions), but with  
intensional semantics.

As for OWL Full I don't know of any papers showing it isn't decidable.  
Yet.

I'll let more knowledgeable people dive in at this point.

Damian

[1]  
<http://annotation.semanticweb.org/iswc2004/annotated_docs/ 
ExtendingTheRDFSEntailmentLemma.htm>
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