[sc34wg3] revised draft Reference Model document N0298

Martin Bryan sc34wg3@isotopicmaps.org
Tue, 16 Apr 2002 09:52:21 +0100


Steve

> Do I understand you to be discussing a third kind of
> thing, which you call "concept"?  Or is "concept" for
> you the same thing as "subject"?

As you know I am strong on the role of definitions. Let me use your Texan
example to explain the difference between a concept, a terrritory and a map.

The concept of Texas can be defined in English as "That part of the United
States under the jurisdiction of the legislative assemblies of  the State of
Texas". Now the advantage of using a concept to define this territory (or
any delineable thing or class of object) is that it is independent of
space-time constraints. So if it is deciced that a county in New Mexico
should be transferred to Texas, or vice versa, then the concept of Texas
does not change. Similarly the concept of Texas did not change when the US
tried to extend its jurisdiction beyond the Rio Grande in the last century.
Territory is always physical. Maps are always simplifications. Concepts
should be "definitions that allow one to determine whether or not the labels
of a topic can legitimately be applied to a particular object).

> A *relationship type* whose instances are relationships
> between published things, on the one hand, and
> publishers, on the other, is absolutely not the same
> thing as the *role* played by publishers in such
> relationships, even if we describe or name both of them
> using the same words.

I agree, but this was not the distiction I was making. The distinction was
between the internal "relationship type" that exists because there is an
association between an ISO13250 topic element that identifies a particular
edition of a particular publication and an ISO13250 topic element that
identifies a particular publishing organization (e.g. the relationship
between the ISO13250 standard itself and ISO and/or IEC) and that between
the "role" of an information occurrence within a particular ISO13250 topic
element and an externally identified organization that happened to have the
same relationship as the association, but which cannot be expressed as such
without creating a new ISO13250 topic element which, for some reason, the
author of the map does not wish to do. The role played by both of these
identifiers is identical, but the way the map is created differs because
there is a fundamental difference between internal references and external
ones within ISO13250.

> You seem to be arguing that
>
>   the act of translating a topic map document into a
>   graph of nodes in which there is exactly one node per
>   subject
>
> should be nondeterministic.

Not my argument at all. I am trying to ascertain whether, if it is necessary
for systems to create more than one node in a dRM to represent an ISO13250
topic element, it is permissible to create nodes of different types to
represent the same ISO13250 topic element. Your rules seem to suggest to me
that this is not permitted.

> > Sometimes the topics in a topic map do not allow you
> > to formally define all the associations that a topic
> > may need.
>
> I don't understand how this can be so.  What prevents a
> topic map author from saying whatever he wants to say?
> How can an author's own <topic>s prevent him from
> declaring any <association>s he wants to declare?

Its not a question of whether he "can" define all the subjects he refers to
but whether he "needs" to. For example, on a web site I manage we
distinguish between different classes of standard producing bodies. We
provide details of "formal standards bodies" as "Diffuse topics", but we
deliberately do not provide details of companies such as Microsoft, Sun or
IBM, that create proprietary standards. Yet we list proprietary standards as
well as formal ones among our "Diffuse topics". For those standards that
have links to bodies that we have provided details of within our web site we
want internal associations between the standard and the information on the
standards body we have chosen to provide. For other standards we simply want
to provide a reference to the external company web site or offices through
an occurrence of a specified type. This is a deliberate policy designed not
to overload the internal map with unwanted information.

> (I do think the question of whether unspecified
> assertion types are implicit, vs. genuinely absent, is
> one of the things that we should all discuss, if only
> to be sure that we understand the implications.)

I'm not sure under what conditions an assertion type can be implied, so I am
unable to comment on this. Hopefully this will be clarified in Barcelona.

> > 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.
>
> I don't understand why you say this.  I believe just
> the opposite: that the dRM is, among other things, an
> attempt to provide a firm foundation on which to define
> durable sets of assertion types, and that the SAM is a
> conscientious effort to define a set of durable
> assertion types, among other things.

I have no doubt you do, or that dRM and SAM will help some applications of
topic maps. What I mean be "well-maintained topic maps" is one that is not
overloaded with unnecessary information that the user has to navigate
through to get to the information he or she needs. As the map's author I
should not have to create a navigable node for every company that ever
submitted an IT standard to the world. I should be able to create a
"relevant subset of standards producing bodies" from those nodes that are of
direct relevance to my user community. Users should only see the set of
nodes whose scope or role meets their requirements profile. This is what I
am looking to achieve using dRM or SAM.

Martin