Re: [xtm-wg] Modified diagram for Association Template

["Thomas B. Passin" <tpassin@home.com>]

Hans Rath has really highlighted the fact that the relation between an
association template and the resulting association is more that a set of
simple relationships, as is stated in Daniels's diagram.  Instead, it is a
type-instance relationship (not, I think, a supertype-subtype relationship).
To capture this properly, there would need to be additional syntax to support
type-instance modeling.  There would also have to be some semantics defined
(in prose, I suppose) to explain the meaning of "type" and "instance" in this
context.

It would be better (clearer) to acknowledge this first and to create the
corresponding concepts, rather than to simply create ad-hoc restrictions.  To
do this properly, it would probably be necessary to be able to reify (as they
say in RDF-land) a template, and to assert that each component of the instance
association would have to be an instance of the corresponding component of the
template.  The definition of "instance" would presumably include all those
kinds of restrictions that Hans is talking about.

That's a lot to do!  No wonder the first edition of Topic Maps didn't have
templates.

Cheers,

Tom Pasin

Hans Holger Rath wrote -

>
> Daniel Rivers-Moore wrote:
> >
> > Attached is a modified graphic for the conceptual model of Association
> > Template.
> >  ...
>
> I miss in all models I have seen so far the possibility
> to control the number of roles in an assoc.
>
> E.g. the assoc template "meeting" has these roles:
> - meeting room (exactly 1)
> - participant (minimum 2, maximum - let's say - 35)
> - chair person (min 0, max 1)
> - minutes (min 0, max 1)
>
> We could express this by metadata assignments
> (= resourceData occurrences) to the template roles.
>
>
> I am also missing the possibility to control the
> possible scope values of an assoc. The mechanism
> should be the same as the one for the role player
> classes.
>
>
> Another issue related to assoc templates are
> topic templates. Why not templating a topic?
> Candidates to be controlled by a topic template
> are:
> - number and kind of topic names,
> - scope of names,
> - number of occurrences of certain type,
> - number and kind of names of occurrences,
> - scope of occurrences,
> - association the topic instance has to play
> a certain role in (e.g. every person in the map
> has to play the "person" role in the "birth" assoc).
>
>
> Furthermore I would like to see a statement in the spec
> that a topic (= player instance) could be of the class of
> the player or "of one of its direct or indirect subclasses"
> (the subclass is defined by the predefined superclass-subclass
> assoc). This would extremely reduce the number of necessary assoc
> templates and role templates.
>
'''


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