[sc34wg3] RM4TM SLUO : Objective or Requirement?

[Marc de Graauw]

* Bernard Vatant

| OTOH if SLUO is only an Objective, it should be expressed by:
|
| Recommendation:
| "In a topic map graph, every subject *should be* (as far as possible)
| represented by a
| single node" [3]
|

* Marc de Graauw

| I completely agree. SLUO can never be more than a (very important) design
| guideline. One can never be sure subjects are actually represented by only
one
| node (topic) since human knowledge is only partial...

* Sam Hunting

| I you were Plato and I was Aristotle, I would agree with you -- indeed,
| subjects (The Subject) is ineffable, etc.

The point is not Plato and Aristotle, but the more mundane ISO 13250:2000
definition of subject:

"In the most generic sense, a subject is anything whatsoever, regardless of
whether it exists or has any other specific characteristics, about which
anything whatsoever may be asserted by any means whatsoever."

XTM and SAM (more or less) follow this definition, and this definition implies
that, even in a fully merged Topic Map Graph, one can never be certain that a
single subject is represented by a single node. So either:

- the prose of 3.9 should be relaxed in the way Bernard suggests, or,
- we should discard the old definition of subject and make a new one.

Effectively, if you maintain "In a fully merged topic map graph, every subject
is represented by a single node." (RM4TM 3.9) you have introduced a new
definition of subject, something along the lines of "that which corresponds to
a node in a fully merged TMG".

| But the point of the RM is to give an operational definition of what "as
| far as possible" means -- that's the purpose of Clause 5.
|
| If that's broken, fine, let's fix it, but I'd rather talk about that than
| partial knowledge.

Clause 5 is fine, as is Clause 6. (Clause 6 does not claim that in a fully
merged TMG has only one node for a subject.)

* Sam Hunting

| (I think, BTW, that "objective" and "design guideline" are close, but not
| identical.
<skipped/>

Agreed, I should have said "objective".

Marc