[sc34wg3] Re: TMDM minor suggestion

Lars Marius Garshol sc34wg3@isotopicmaps.org
Thu, 15 Dec 2005 17:08:50 +0100

* Robert Barta
> I lied, of course.

No suprise there.

(Nice statement to quote completely out of context, of course. :-)

> It says:
>    Constraint: Duplicate item identifiers
>    It is an error for two different information items to have strings
>    that are equal in their [item identifiers] properties, unless they
>    are topic items. If they are topic items they shall be merged
>    according to the procedure in 6.2.
> So it says, that it can never be the case that in an TMDM instance
> there are two different topics with the same value as identifier. If
> there were, then the topics are not merged, violating TMDM.
> For non-topics it also can never be the case that in an TMDM instance
> there are two different items have the same value there.
> So why not say "No two items in an TMDM instance can have the same
> item identifier". Maybe add the above explanation as Note....

Hmmmmmmm. You're right. That actually does work much better. Thanks!

> [6.2, point 8]
> 2) and 3) only seem to replace the _involvement_ of A and B throughout
> the instance. But A and B as topic items still remain, or not? Maybe I
> just have another interpretation of 'replace'?

Since they are replaced in the topic map.[topics] property in steps 2  
and 3 having an extra step which removes them would be nonsensical,  
since they can't be in that property any more. (It is possible to  
make this more explicit, though, but I'm not sure if there's any point.)

As for whether they still "remain" in the sense that they still exist  
I think is more of a metaphysical question. I guess that's not what  
you meant.

Lars Marius Garshol, Ontopian                  http://www.ontopia.net
+47 98 21 55 50                                http://