[sc34wg3] revised draft Reference Model document N0298

Martin Bryan sc34wg3@isotopicmaps.org
Mon, 15 Apr 2002 08:20:11 +0100


Steve

> If you believe we should stop invoking the "map
> vs. territory" distinction by means of the
> terminological dipole of "topic" vs. "subject", then
> maybe we can call nodes in graphs "subject nodes".
> What do you think about that idea?

I like the idea of using "subject nodes" to identify what dRM records. This
is what they are in the model. They are "the points in the model at which
this concept (what you seem to call the "territory" of the "subject", a
phrase I am not sold on) is used".

> If we're religious about saying "topic node" when we
> mean node, then why shouldn't we also be religious
> about saying "<topic> element" when that's what we
> mean?

No particular reason, though I object to having to use the angle brackets,
especially as these fail to make it clear that the attributes of a "topic
element" are more important than its content (if you don't believe me try
writing topic maps without identifiers!)

> I don't think it would be right to do that.  I don't
> see how a subject that is a role can be the same
> subject as a subject that is an assertion type -- even
> if both subjects happen to have the same name.
>
> > I quoted the example of a topic called
> > "PublishedBy". This could be an association
> > type.
>
> Sure, it could be, but *is* it?  It is the topic map
> author's responsibility to have exactly one subject in
> mind for each topic.

I deliberately chose PublishedBy as an example of something that can both be
internal to the topic map and external to the topic map without changing the
basic concept of "having been responsible for the publishing of". I can see
this concept as being both a valid occurrence type and a valid end point of
an association. I see no point in having to create two topic elements, one
for "the association of being responsible for publishing" and one for "the
role of being responsible for publishing". I can understand, however, why
two topic nodes might be needed for this purpose.

The problem I have with much of the work currently being done with topic
maps is the implied conclusion that internal associations are more important
than external relationships. This is clearly not the case. In my opinion a
topic map is only as useful as the external resources it leads users to.
Without being able to identify the use of topics in information resources a
topic map cannot be used to enhance the semantic web. Sometimes the topics
in a topic map do not allow you to formally define all the associations that
a topic may need. In such cases you are forced to used occurrences to point
to resources outside of the topic map to define associations. The concept
that you must "create a topic for any association you wish to express" is
not one that appeals to me, nor one that makes long-term sense for topic
maps. We need to have well-maintained topic maps, with well defined
associations, if we are to ensure that they will be usable over time. The
current models do not seem to be helping this goal.

Martin