Re: TMDM and merging associations

* Lars Heuer
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| Personal note: ... I think roles should neither have an reifier nor iids.

It's a question, of course, of the degree of expressivity that you want to permit.

Or, as SRN might express it: whether you want to be able to regard association roles
as subjects. It was implicit in the original (HyTime) version of Topic Maps that the
answer to this question was 'yes' and, after careful deliberation in 2000 and 2001,
it was decided to make that answer explicit in XTM.

To date very few applications have taken advantage of this possibility, but the same
applies to reification in general. That doesn't necessarily mean it was wrong to
include the capability, only that the full power of Topic Maps has yet to be
harnessed (which I think we all know anyway).

I (personally) believe there will come a time, as topic maps become more and more
complex, when users will start to feel the need to -- and see the advantage of being
able to -- talk about a particular subject from the (restricted) perspective of its
relationship to some other subject.

Lars disagrees, as is his right. However, while removing [reifier] and [item
identifiers] from Association role items would make the model a little lighter, it
would also make it considerably less expressive and non-backward-compatible. I don't
think that would be a good thing.

Steve