W3C home > Mailing lists > Public > www-webont-wg@w3.org > December 2001

Re: proposal for working on the ontology language

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Tue, 11 Dec 2001 21:57:12 -0600
Message-Id: <p05101003b83c81c283fe@[65.212.118.193]>
To: Jim Hendler <hendler@cs.umd.edu>
Cc: Tim Finin <finin@cs.umbc.edu>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, www-webont-wg@w3.org
>Accroding to W3C policy, one of my main roles as chair is to rule on 
>what is in and out of charter.  As with all such, I open these to 
>discussion, but will eventually need to rule if consensus isn't 
>reached.  Rules was easy because it was explicite in the charter - 
>here are my initial reactions to Leo's questions, but please let me 
>know if you think differently.
>
>At 6:14 PM -0500 12/11/01, Leo Obrst wrote:
>>If rules are outside our charter, what about statements of equivalences
>>between 2 ontologies (e.g., for semantic mappings for the content
>>interoperability use case)? I believe DAML+OIL just has
>>daml:sameClassAs (class expressions)
>>daml:equivalentTo (class or property expressions) [and when applied to
>>properties, is the same as samePropertyAs]
>>daml:samePropertyAs (property expressions)
>>
>>Is this sufficient? I think these are ontology-internal constructs, no?
>>Might they be used across ontologies?
>
>
>Our charter reads "In addition, the language must support the 
>development and linking of ontologies together, in a web-like 
>manner."   Therefore I see this as clearly within charter.

With respects to whoever wrote the charter, that seems like a damn 
silly consequence of it. Rules are not that hard to get right; the 
topic is about 30 years old, it is fully grounded in theoretical 
(semantic) analyses and many years of practical experience, and 
implemented systems probably number in the hundreds; and while there 
are some genuine disagreements (mostly about the importance of 
closed-world reasoning) , the issues are fully understood. On the 
other hand, mappings between ontologies (not linking them, but 
designing a framework to allow coherent mappings between 
vocabularies) is a research area which is largely unexplored, has no 
clear methodology or theoretical framework, perhaps fewer than half a 
dozen implemented systems, if that, and seems to be extremely hard, 
being connected with unsolved logical issues and mired in deep 
controversy (read the SUO archives, for example). So we are forbidden 
to even consider the first, but encouraged to tackle the second. 
Great. I guess this is what we have managers for, right?

>  I do see that ultimately there may be some grey area between 
>linking ontologies and rules, but for now I think we can 
>differentiate these clearly enough to stay out of trouble.
>
>>
>>I also note that there is no meta level to DAML+OIL and I think that was
>>a conscious choice, no?, though I don't know the history of that
>>decision. Sometimes having a modifiable meta level is a very good thing
>>(future language extensions, e.g.)
>
>I don't see why this would be out of scope, although it seems fairly 
>ambitious given where we are and where we are trying to get to.  I'd 
>say that if there is a clear need for this expressed in the use 
>cases, and a clear consensus in the group that this should be 
>pursued, it is doable.

Jim, are you serious? If you think that inventing a language with a 
clear semantics that can describe its own metatheory is 'doable' by 
the webont committee (or indeed by anyone on the planet in the next, 
say, five years), I will enjoy sitting back and watching y'all try to 
do it. It will be like shooting fish in a barrel.

Pat
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Received on Tuesday, 11 December 2001 22:57:22 GMT

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