[topicmapmail] Contextualized Topic Maps.

[Murray Altheim]

Olivier Lamborelle wrote:
> 
> Murray Altheim wrote:
> 
>> Olivier Lamborelle wrote:
>>
>>> Thomas Schwotzer wrote:
>>>
>>>> "The roles a topic plays in associations are among the characteristics
>>>> that can be assigned to it and are therefore governed by scope." 
>>>
>>> That's incorrect I think.
>>
>> No, that is correct. I think I perhaps used a quote that didn't exactly
>> illustrate the point I was trying to make though, which is clarified in
>> my recent reply to Thomas. 
> 
> Can you clarify this for me: does the 'it' represent 'a topic' or 'the 
> associations' in this sentence?

Well, I was quoting from the XTM spec, but you've pointed out a rather
unfortunate ambiguity in its use of language.

> If I understood correctly this sentence, all characteristics that can be 
> assigned to topic (or to associations?) are governed by scope? does 'governed' 
> mean 'can be scoped' ? In my view only the basename(s) and the occurrence(s) are 
> the characteristics (of a topic) that can be scoped.

No, the roles played in associations can be scoped, as explained below.

> The role a topic plays in associations is according to me a very special 
> characteristic of a topic:
> - it is somewhat stored outside of this topic (in an association element)
> - it can not be scoped (or the scope is applied to the association hence to all 
> members)
> 
> That's why I really don't like this sentence. :-)

No, I agree. It isn't a good one.

I remember a diagram Eliot Kimber drew when we had our Paris meeting,
that showed a Topic's "binding point" (a concept we don't use in the
spec, but nevertheless exists, as the point around which all topic
characteristics are "bound"), and that there were three kinds of
topic characteristics available, each capable of being scoped:
basenames, occurrences, and roles played in associations. If you
check the note following section B.8 of XTM 1.0's Conceptual Model
you'll see a clarification, i.e., that any topic characteristic can
be scoped, but that:

   NOTE: In XTM, it is not permissible for the different Roles in
   an Association to be governed by different Scopes. The XTM syntax
   expresses the Scopes on all the Roles of an Association through a
   single <scope> subelement of the <association> element.

Which semantically performs the task correctly, I believe. If you
think about an example, "John plays the role of husband" in a
"marriage" association with Frank (to keep up with the times). Now,
this association can be scoped, say, by time "1998-2003". It
wouldn't make sense to scope the role itself; it's the association
that gets scoped (e.g., by time).

Sorry for all the confusion. I hope this helps.

Murray

......................................................................
Murray Altheim                    http://kmi.open.ac.uk/people/murray/
Knowledge Media Institute
The Open University, Milton Keynes, Bucks, MK7 6AA, UK               .

    LEO (July 23-Aug. 22): When he first invented the printing press
    in the fifteenth century, Johannes Gutenberg used it to fashion
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