[sc34wg3] RM4TM SLUO : Objective or Requirement?

Lars Marius Garshol sc34wg3@isotopicmaps.org
23 Nov 2002 11:41:39 +0100

* Bernard Vatant
| Question en paasant : Why not use the word "topic" instead of "node"
| throughout? 

* Sam Hunting
| Steve will correct me, but in the same way we tried to reserve
| association for the SAM, and assertion for the RM, we tried to
| reserve topic for the SAM, and node for the RM.

I think this was good practice and a very good decision. We would very
quickly cause problems for ourselves if we used the same terminology
for the constituents of different models.
| 3.4.1 does mean what it says -- "every node represents a single subject."

That's not the problem. The problem is when RM4TM says the obverse:

  "every subject is represented by a single node"

since that is something no set of merging rules can guarantee. The
effect of what 3.9 says:
| See also 3.9:
|    In a well-formed topic map graph, every node represents a single
|    subject, but some subjects may be represented by more than one node. In
|    a fully merged topic map graph, every subject is represented by a
|    single node. 

is that it is unknowable when a TMG is fully merged, because being
able to verify this requires both deep subject matter expertise and
deep knowledge of what the author intended. The full identity of each
subject may not even be known.

The real problem here, I think, is that RM4TM defines terms for TMGs
at two different levels of "conformance", but only one of them can be
tested automatically. I think it is far better to say that in a
fully-merged TMG there are no more merges left to be performed
according to the merging rules.

The SAM has the following to say in section 4:

  Merging is a process applied to topic map information in order to
  reduce the number of redundant topics representing the same
  subject. This specification requires merging to be performed in
  certain cases, but these are insufficient to guarantee that there
  will always be one topic per subject. Applications are therefore
  allowed to merge topics in cases where it is not clear that the
  topics represent different subjects.
| An objective like the SLUO is just that -- a goal, an end, a telos,
| that for which we strive. In the real world of engineeering
| constraints, trade-offs must be made, but that doesn't mean that the
| overall objective is not sound.

Sure, but you should be careful not to make the term "fully-merged"

Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
ISO SC34/WG3, OASIS GeoLang TC        <URL: http://www.garshol.priv.no >