[sc34wg3] Feedback on TMDM

Robert Barta sc34wg3@isotopicmaps.org
Thu, 28 Apr 2005 12:22:36 +1000

On Wed, Apr 27, 2005 at 04:48:39PM +0200, Lars Heuer wrote:
> >> [...]
> >> > - 5.1: Constraint
> >> 
> >> >   They cannot be the same unless items are topics. In that case, these
> >> >   have to be merged. So there is only one topic afterall. So the source locators
> >> >   are different afterall for _EVERYHTING_! Or not?
> >> 
> >> I don't understand the last but one sentence. :(
> [...]
> > If the [source locators] are the same, then the two have to be merged
> > in the first place, so there is only one. And no conflict. So the
> > restriction "unless they are topic items" sounds superfluous to me.
> Thanks for the explanation. I don't think that restriction is
> superfluous because the main intention is to explain that
>   "It is an error for two different information items to have string
>   that are equal in their [source locators] [...]"

I do not say, that the constraint itself is superfluous. I think the
_restriction within the constraint_ is misleading.

> And to explain that it is not an _error_ if topic items have the same
> source locator, because they are fulfilling one of the "equality
> rules" in "5.3. Topic Items" and must be merged.

Again: Topic items _cannot_ have same source locators, because TMDM
forces these to be merged into one. So this situation can never arise.