[topicmapmail] TMRM and TMDM: little differences between assertion and associations

[Thomas Schwotzer]

The ISO 13250-2 document defines the TM data model whereas
123250-5 defines the TM reference model.

I'm a bit puzzled of some little discrepancies.
One example:

In the reference model, assertions are means to
define relations between (component) subjects and
(component) topics. Paragraph 5.1.3:
http://www.isotopicmaps.org/tmrm/TMRM-3.10/TMRM-3.10.html#parid3059

"The subjects that are the roles that can be played in this
relationship.
Topics that represent such subjects are called r-topics. The r stands 
for role. Every assertion has two or more r-topics. No two relationship 
types have any roles in common."

In my understanding, associations in DM are means to define
assertions from RM. In the diagram at
http://www.isotopicmaps.org/sam/sam-model/#sect-association
an association has 0..* roles.

0..* in the data model
2..* in the reference model

The Data Model seems to be more sloppy (what I'd also prefer).

There are a view other (little) discrepancies like this.
I'm sure, the DM editors are aware of the RM document.
But where came the differences from?
Is it intended to change the RM? Is it allowed to soften
the RM requirements? Or do I misinterpret both documents?

Maybe, it's an academic problem. Nevertheless, I'm curious.

Cheers, Thomas
-- 
Thomas Schwotzer
University of Technology Berlin
Intelligent Networks and Management of Distributed Systems
http://ivs.tu-berlin.de/Schwotzer
fon: +49-30-314-79834 fax: +49-30-314-24573