[sc34wg3] Individual contribution on the U.S. N.B. position o nthe progress ion of Topic Map standards

Jan Algermissen sc34wg3@isotopicmaps.org
Sat, 03 Apr 2004 13:52:43 +0200

Robert Barta wrote:

> I appreciate the approach many people have to first define a data
> model to somehow capture the information they have in mind. This is
> what RM/SAM/TMDM all try to do with varying degree of ... elegance.
> But to define what a data structure really "is", it's meaning, the
> whole gist of it, you can _only_ do with ..... operations.

IMHO, the data model is what enables you to reason about operations.
If you do not know about the notion of 'topic' and that topics may have
properties (no matter whether TMDM or RM) there is no way to talk about
operations on topics and properties.

In your stack example, the data model is (in a broad sense) object orientation:
you know you can represent a stack as an object and that you can invoke 
methods on it. You know that objects have identity etc.
So, no operations without a data model.

What I think (and I think this is what you actually refer to) is that
there must not be anything in the data model that goes beyond the
basics that enable to talk about the 'operations'.

Regarding the RM, the aim is exactly this essence.

In the case of the TMDM it is also the essence (here using the XML
infoset formalism) but the TMDM also adds semantics (What is a name?,
what is an occurrence?)[1]


[1] Off thread (trying to explain rather to start a fight): These
    additional or inherent semantics are exactly the difference between the
    two camps (RM vs TMDM). IMHO, the semantics are harmful because they
    complicate the model and hide the structural essence that the RM is
    trying to find (or hopefully has found). 

    For example, the TMDM needs several object types (Topic, Association,
    Occurrence, etc) while the RM needs only one (Topic).

Jan Algermissen                           http://www.topicmapping.com
Consultant & Programmer	                  http://www.gooseworks.org