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Re: ISSUE-3: REPORTED: Lack of anonymous individuals

From: Carsten Lutz <clu@tcs.inf.tu-dresden.de>
Date: Thu, 08 Nov 2007 14:33:39 +0100 (CET)
To: gstoil@image.ece.ntua.gr
Cc: Boris Motik <boris.motik@comlab.ox.ac.uk>, public-owl-wg@w3.org
Message-id: <Pine.LNX.4.64.0711081430570.20348@frege.inf.tu-dresden.de>

On Thu, 8 Nov 2007, gstoil@image.ece.ntua.gr wrote:
>
> Carsten Lutz <clu@tcs.inf.tu-dresden.de> said:
>
>>
>> On Thu, 8 Nov 2007, gstoil@image.ece.ntua.gr wrote:
>>>
>>> Carsten Lutz <clu@tcs.inf.tu-dresden.de> said:
>>>
>>>> relation. Actually, we could think of adding the universal property
>>>> and interpreting the anonymous individuals as skolem constants, as you
>>>> propose. This means that, if really needed, true anonymous individuals
>>>> can still be recovered via the universal property. The restriction to
>>>> tree-shaped interconnections is then automatic. And we don't introduce
>>>> conjunctive queries to ontology entailment.
>>>>
>>>> greetings,
>>>>
>>>>  	Carsten
>>>
>>> But is there currently any reasoning support for the universal role in SROIQ?
>>> I believe there isn't any.
>>
>> Yes, it is in SROIQ. But even if it wasn't: it's useful, it's easily added
>> to tableau algorithm, and it shouldn't be difficult to implement.
>>
>> greetings,
>>  		Carsten
>>
>
> But from the paper of SROIQ I am reading the following:

That's just what I wrote: disallow it in...

> Def 2: "A RIA ... not including the universal role"

...role inclusions

> Def 3: "For roles R,S != U..."

...role property assertions (because the properties of the universal
role are fixed)

> Def 15: "...let C_o be a SROIQ-concept not using the universal role..."

...number restrictions (because you would have to do finite model reasoning
if you allowed that).

But *do* allow it in existential and universal restrictions.

greetings,
 		Carsten

--
*      Carsten Lutz, Institut f"ur Theoretische Informatik, TU Dresden       *
*     Office phone:++49 351 46339171   mailto:lutz@tcs.inf.tu-dresden.de     *
Received on Thursday, 8 November 2007 13:33:54 GMT

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