[CL] Question about exclusion list in modules

[Murray Altheim]

John F. Sowa wrote:
> Pat and Chris,
> 
> I've been trying to see how the exclusion list
> is intended to be used.
> 
> In any version of logic of any kind, it is always
> possible that inconsistencies might be created when
> you import text M into text T, because M and T might
> use the same names in inconsistent ways.  Such "name
> clashes" are possible with any kind of language.
> 
> But if you're importing M from a segregated language
> into CLIF, the imported text M would presumably not
> quantify over any of the names in the exclusion list.
> So what exactly is the purpose of the exclusion list?
> 
> Can you give any examples of how that list might block
> some inconsistency that would occur if you did not have
> the exclusion list?

John,

I'll certainly leave Pat or Chris to answer this authoritively,
but from the perspective of the XCL syntax, and from my rather
extensive experience in authoring XTM-based ontologies, I'd
say that the exclusion list is a very good idea. When I've
written XTM ontologies, which are generally modular, I've used
quite a number of utility Topics that aren't really part of the
ontology itself but are required to make things function. I
think the idea of being able to explicitly exclude (rather than
include) terms in an ontology is a great idea, and in XCL we've
currently got an <exclude> element for this purpose, e.g.:

    <exclude>
       <term name="cow"/>
       <term name="pig"/>
       <term name="moose"/>
    </exclude>

This simply excludes the terms (names) from the specific module
in which they occur.

Murray

......................................................................
Murray Altheim                          http://www.altheim.com/murray/
Strategic Services Development Manager
The Open University Library and Learning Resources Centre
The Open University, Milton Keynes, Bucks, MK7 6AA, UK               .

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