[sc34wg3] TMDM / XTM 2.0 vs. XTM 1.0 "reification" procedure

[Lars Heuer]

Hi,

>> a) Topic with subject identifier "foo", name with item identifier
>>    "foo" => no problem, no special meaning

[...]
> To me it seems that the correct thing to do here would be to:

>    1) keep the equality rule for topics as it is, and

>    2) add a constraint stating that your case a) is not allowed.

What does "not allowed" mean?

Example: Topic Map A:
         contains a topic with the subject identifier "foo"

         Topic Map B:
         contains a name with the item identifier "foo"

What happens if I like to merge A + B?

The new XTM makes the situation even worser because the item
identifiers are exported.
If someone collects XTM 2.0 documents from different sources and tries
to merge them into one topic map it might not be unlikely that they
are not mergeable because of item identifier clashes.

While writing these lines it occurs to me that the export of item
identifiers may be a serious issue of XTM 2.0 and can make XTM
unusable or difficult as interchange syntax.

[...]
> Any thoughts on this?

IMO the cleanest solution would be: Remove item identifiers from the
topic map constructs != topic.
Up to date nobody has told me why they are making sense on them.

Another solution might be:
If a topic map construct != topic has a item identifier that is used
as subject identifier, the reifier property is automatically set and
the item identifier and subject identifiers are deleted (if I remember
right this was the process to achive merging in an older XTM 1.1
draft).


Best regards,
Lars
-- 
http://semagia.com