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RE: Re[1] DAML-ONT: the case for closedness

From: Je'ro^me Euzenat <Jerome.Euzenat@inrialpes.fr>
Date: Tue, 24 Oct 2000 22:07:05 +0200
Message-Id: <p04310102b61b8475d882@[]>
To: pat hayes <phayes@ai.uwf.edu>
Cc: www-rdf-logic@w3.org

In his message (RE: Re[1] DAML-ONT: the case for closedness) of 23/10/00,
pat hayes wrote:
>>The situation I had in mind at the beginning is not that simple. The point is
>>in having three Ontologies:
>>- myO, your ontology for whatever that you will build,
>>- bigO, the well-known ontology that anybody uses in your field and 
>>that you know you can trust very much.
>>- theotherO, the ontology that is provided by the little startup 
>>you don't know if you must trust but that provides you with the 
>>lastthing widgets in ebusiness and that claim to be bigO compliant.
>>	Well, you would like to be able to use these in such a way 
>>that even if theotherO is flawed in some parts (that maybe you do 
>>not use), this cannot affect the well-established concepts that you 
>>know from bigO.
>>	Unfortunately, due to the open character of the definitions, 
>>someone can come and restrict a definition of a concept in bigO 
>>(and this can be silent because it does not raise incoherence, just 
>>restrict one or two extensions).
>No, wait a minute. Only those with access to the bigO site can 
>actually alter the information on that site (and even that wouldn't 
>be playing by RDF rules). Someone else can publish a restriction on 
>a different page: say, quantumO, which can make some claim 
>(including a restriction) using the bigO vocabulary. That does not 
>change the meaning of bigO#foo , however. If you want to refer to 
>the restricted meaning, you would use quantumO#foo. To put the 
>matter in a nutshell, no content can pass along a web reference in 
>the direction of reference: it can only be used by the referring 
>page to constrain the meanings of its own symbols.

That is the rule for HTTP.
But I am not sure that this was the intended rule for DAML. Again, we 
would need semantics here to be sure of that.
All RDF is about making statements about referenced objects. It is 
not about creating new objects. Let me write, in quantumO:

	equivalent( bigO#foo, Nothing ).

Of course, this does not change anything for those who do not use quantumO.

Again, I am not considering philosophy here, but the modularity of 
the "semantic web" construction:
- If we cannot rely on distributed pieces of ontologies, and we are 
waiting for centralized one: it will not scale,
- If we do not add some mechanisms ensuring some robustness of the 
system: it will collapse.
That is a design issue, a very difficult one, and I do not pretend 
that I know how to solve it. But for sure, this is an issue.

>>	So the point is: I trust bigO for sure. I am not really 
>>confident about theotherO, but their new concepts are interesting 
>>and they are bigO compliant (let say that I can still use the 
>>concepts I know very well from bigO with their stuff).
>>	Now, DAML does not provide any way for the bigO makers to 
>>force some compliance.
>Just as it provides no way to force someone to vote, or to hold a 
>particular religion. Nothing but military actioncan *force* 
>compliance, and maybe not even that. The best one can do would be to 
>ensure that any false claim of compliance can be publicly checked 
>for falsity, but has to be up to the actual user to do the checking.

Of course, my writing was loose, we agree here. Let me rephrase my statement:

"DAML does not provide any way for the bigO makers to provide some 
conditions for bigO-compliance"

Now, closedness conditions as I proposed them are very easy to check 
(linear) and can be implemented in DAML parsers.
  Jérôme Euzenat                  __
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Received on Tuesday, 24 October 2000 16:07:57 UTC

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