>. My thesis is also that roles should not be subsumed
> under people (persons) but neither the reverse as you suggest as your
> general solution: I hold that they should form two independent
> hierarchies (multiple classification; IF roles are naturally best
> described by is_a hierarchies, which I doubt.)

Roles are assigned to tasks, which are performed by departments of
organizations.

>Anyway your example is
> ambiguous: I do not understand whether you mean is_relations and
> part_of relations: anyway, in both cases we get problems:
> >In general you have a structure such as:
> >    Organization
> >        Department
> >            Position
> >                Person
> >where role is defined by the position held.

What I should have done was show the generalized hierarchy as

Organization
   Department
     Task
       Result
          Responsible Person

which are all linked by HAS_A relationship. This is a part-of relationship
in most cases, but I'm not convinced that it is part-of for the last link in
the tree:-(

> A department IS not an organization etc, it is PART of an
> organization etc. However, if we take the hierarchy to mean
> partinomy, than a person is part of a position. This cannot be what
> you mean (neither that a person IS a position). Probably you may want
> to express that a (generic) position may be held by more than one
> person? Can you be more explicit?

I meant that, and also that, as my example showed, the same person can play
the same role in different organizations at the same time, something that is
difficult to show if you insist on assigning the role to the person. Roles
belong to tasks.

> I share your intuition that organizations are built from roles. In
> fact, in the ontology I am developing an organization is an assembly
> of two entities: positions (reflecting the `responsibility'
> hierarchies in arganizations) and roles (reflecting the kind of
> activities that a person taking a role is required to execute).
> However, I am not sure that this is a sharp distinction, because in
> many respects for instance legal roles and legal positions mean the
> same...
> (another topic for debate...)

One person can undertake many tasks for an organization, which may be
assigned to different departments, though the person only reports officially
to one of the departments. (Consider the task of cleaning a department's
offices each night: its rarely done by a member of the department.)
Responsibility for administration and responsibility for tasks are often not
parallel.

Martin Bryan