Re: [topicmaps-comment] TAO vs. ERA

[Robert Barta <rho@bigpond.net.au>]

On Fri, Jan 11, 2002 at 07:26:17PM +0100, Lars Marius Garshol wrote:
> The same applies elsewhere, so Norway would be "country", "container",
> "containee", "neighbour" (of other countries), "member" (of various
> organizations), etc etc. Clearly, this doesn't work. Norway plays all
> of these roles, but that is different from being an instance of them.
> 
> This doesn't mean that one couldn't explictly assert that Mozart is a
> "composer", but I am kind of uneasy about it. It should be done with
> care. 

In the introductory papers I often read that 'instanceOf' is a special 
association and a shorthand form for

(is-specialisation-of)
specialisation: my-thing
general-thing: my-class

For associations I can choose a scope to constrain its validity,
for instanceOf I can not. In other words, the scope of an instanceOf
is then the unconstrained-scope? Do I interpret something into the
standard which is not here?

> Doesn't that match how we use the topic in a topic map? Composer is a
> concept. You can be an instance of it, or you can play it in relation
> to a piece of music. I being useful as a role does not stop you from
> being used for other things.

Really? The type 'composer' is as you said earlier 'socially
accepted as concept'. Here we are thinking about people playing
some instrument and denoting the tune of songs, operas, musicals...

Playing the role 'composer' in an association is different to me, 
in a subtle sense. Here it is only relevant in the context of the
association:

(composes)
composer: roger-waters
album: the-wall

> | It can be worse. Consider "documentation" that can be considered as
> | a topic type (a set of documents), as a role (in a
> | subject-documentation) or as this latest association type itself
> | (the fact of documenting something) ... There again, you should
> | define three different topics:
> | 1. documentation-as-topic-type
> | 2. documentation-as-role-specification
> | 3. documentation-as-association-type
> 
> I think 1 and 2 are the same here, while 3 is probably not...

Hmmm. This was not really a practical problem yet, so I hope
this is an academic discussion. ;-)

\rho