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Re: Proposal and Test cases (Re: skolems: visible differences?)

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Thu, 17 Jan 2008 14:43:47 +0000
Message-Id: <88CE620B-1F43-4023-8C16-7C68C4A17764@cs.man.ac.uk>
Cc: "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>
To: Jeremy Carroll <jjc@hpl.hp.com>

On 17 Jan 2008, at 14:22, Jeremy Carroll wrote:

> Bijan Parsia wrote:
>> Furthermore such variables have far reaching consquences both
>> formally (e.g., on the data complexity of RDFS; undecidability of  
>> OWL DL+ cyclic bnode patterns; what sorts of entailments occur)
>
> Remind me about the "undecidability of OWL DL+ cyclic bnode  
> patterns" - I seem to vaguely remember briefly getting my head  
> round it once, but it's gone.

See Boris' explanation:
	http://www.w3.org/mid/000701c82200$d343cf00$2711a8c0@wolf

> Is the statement that say using the existential semantics with  
> bnodes for individuals in OWL DL takes us into undecidability?

IIRC, you need inequality as well, but yes. Ah yes, see his even  
earlier explanation:
	http://www.w3.org/mid/000601c82176$e8a3b700$2711a8c0@wolf

It contains the reference.

Cheers,
Bijan.
Received on Thursday, 17 January 2008 14:42:00 GMT

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