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Re: ISSUE-5: n-ary datatypes - decidability on merging

From: Carsten Lutz <clu@tcs.inf.tu-dresden.de>
Date: Tue, 13 Nov 2007 18:48:58 +0100 (CET)
To: Jeremy Carroll <jjc@hpl.hp.com>
Cc: Alan Ruttenberg <alanruttenberg@gmail.com>, public-owl-wg@w3.org
Message-id: <Pine.LNX.4.64.0711131839110.27760@frege.inf.tu-dresden.de>

On Tue, 13 Nov 2007, Jeremy Carroll wrote:
> Alan Ruttenberg wrote:
>> I'm not sure how to characterize the interactions. For instance there are 
>> issues around combining cardinality restrictions with transitive roles that 
>> can be triggered on a merge.
> These can only be triggered when the two ontologies being merged each contain 
> one or more axioms mentioning a proeprty in common, and those axioms violate 
> some condition.
> And ditto with your other examples.

In some sense, the same is true with your own example. If I merge two
ontologies O1 and O2 where Oi uses a decidable datatype group Xi for i
\in {1,2}, and the union of X1 and X2 is undecidable, then reasoning 
about the union of O1 and O2 poses no problem if O1 and O2 share no 
datatype property because X1 and X2 do not interact.

I mean this on an anstract and intuitive level. It may not be reflected
in the Pan-Horrocks formalization, I don't know. The point is, it *could*
easily be formalized. But it would look somewhat awkward. The question
is: is it worth it, only to get well-behaved mergers of, as you say,

> what about two almost completely independent  OWL-DL ontologies?

Personally, I don't think that this scenario is of such great importance
that we should sacrifice an easy and comprehensible definition of n-ary
datatypes to make it work.

Anyway, regarding this point of your criticism, I disagree that things
are not properly understood. In my opinion, they are. But there is no
one perfect solution that gives us everything we (resp. you :) want. We
have to find a good balance, but I cannot see that we need 10 more years
of research to get that.


*      Carsten Lutz, Institut f"ur Theoretische Informatik, TU Dresden       *
*     Office phone:++49 351 46339171   mailto:lutz@tcs.inf.tu-dresden.de     *
Received on Tuesday, 13 November 2007 17:49:12 UTC

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