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

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Tue, 13 Nov 2007 10:22:00 -0500
Message-Id: <7D522D68-E950-457B-8705-16D2BAA5FD64@gmail.com>
Cc: public-owl-wg@w3.org
To: Jeremy Carroll <jjc@hpl.hp.com>

On Nov 13, 2007, at 8:58 AM, Jeremy Carroll wrote:

> Alan Ruttenberg wrote:
>> Hello Jeremy,
>> When you say "merging" what exactly do you mean? Do you mean the  
>> combination of two OWL-DL ontologies to make a third?
>> -Alan
>
> Yes - for instance if party A publish ontology AA, B publishes BB, and
> C publishes CC which imports AA and BB. An important question for C  
> is do AA and BB interact, and if C is working on OWL DL, what  
> constraints are placed on AA and BB.
>
> While there are some plausible unfortunate interactions in OWL 1.0  
> DL, these are to do with interactions over vocabulary items.

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.

Speaking as a user, I don't currently have the expectation that the  
merge of two OWL-DL ontologies will yield yield an OWL-DL ontology.  
My gut is that we don't want to make this a restriction as we would  
land up over constraining our ability to add useful features.

More merge issues come up with subproperty chains.

Regarding N-ary datatypes, for the first part of this I think we need  
to start talking about this in a way that people might understand.  
Vipul, when he raised the question of working with linear inequations  
in OWL, did not recognize the connection to N-ary datatypes.  To me,  
this adequately demonstrates that we need to rephrase how we discuss  
this feature in the specification and in our documentation.

I'm pretty sure that most application developers would gladly trade  
some risk on merge for the ability to have  linear inequations in  
OWL, but we could certainly test that with a survey.

-Alan

>
> In the datatype groups work of Pan and Horrocks, the mergeability  
> of datatype groups is weak, and so problems in this area are expected.
>
> Jeremy
>
Received on Tuesday, 13 November 2007 15:22:40 GMT

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