Re: [topicmaps-comment] TAO vs. ERA

[Lars Marius Garshol <larsga@garshol.priv.no>]

* Bernard Vatant
|
| I agree considering "murderer" as a type is controversial. I'm
| uneasy myself to be classified as "webmaster" because I maintain a
| website, "teacher" because I've been through that for quite a while,
| "consultant", "chair", "speaker" because now and then I assume those
| functions, "customer" because I buy products and services, and so
| on. Inheritance of all types defined by those roles leads to heavy
| multi-classification with no real interest.

I agree very strongly with this. Moriarty is a "person", who happens
to have played the role of "murderer". If you are going to let role
types also serve as the types of the role players you have to do it
everywhere, which means that whoever played "victim" to Moriarty's
"murderer", will get the type "victim", which IMHO is obviously wrong.

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. 
 
| But it remains a certain number of cases where role and type are
| very difficult to sort out. I think "composer" was indeed such kind
| of example in the scope of classical music.

Yep, mainly because "composer" is a special kind of role, in the sense
that it's socially considered to confer a kind of identity onto the
player of that role in a way that, say, "victim", or "containee", do
not. 

| The difficulty comes when you have to decide if the topic used for
| the role specification
| (composer-as-role-type-in-a-composition-association) should be
| merged or not with the topic used for classification
| (composer-as-subclass-of-artist). 

To me these seem to be the same. Why would you consider them separate? 

| You can do it when you create a topic map from scratch, with
| explicit different names and topic ids for "composer-role" and
| "composer-type" for example.  But if you try to import a classical
| database or thesaurus or whatever classification, you will have hard
| time to make a parser figure which is which, since the same term
| "composer" or tag <composer> will have either semantics ...
| depending on context.

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.

| 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...
 
--Lars M.