[sc34wg3] RM4TM issue : is role player always a set?

Lars Marius Garshol sc34wg3@isotopicmaps.org
23 Nov 2002 12:14:06 +0100

* Bernard Vatant
| That is the way I understand the logic of RM4TM. But if it is, we
| need a specific representation of the set-member relationship.

* Steven R. Newcomb
| Now, here, I agree with you, Bernard!  It's something I think the
| SAM cannot avoid doing.  And, maybe, the SAM will define different
| *kinds* of sets, too.  I don't know.  (I'm not proposing such a
| thing; I'm merely recognizing the possibility.  I tend to think we'd
| do better to define a single, totally generalized "set-member"
| assertion type.)

As I said in my reply to Sam the SAM needs sets for one single purpose
and beyond that it has no relationship with sets. The only issue here
is to make sure that the sets used by the RM-SAM mapping fit with
those used by the SAM itself. 

What the RM does for its internal purposes is actually a whole
different piece of cake and we don't need to worry about matching
these two up. (Well, maybe you need to worry slightly, since it is
better to reuse the same set notion for both cases, but it's not a
major issue.)
* Bernard Vatant
| Otherwise, what are the role players in the set-member assertion? We
| have a recursivity problem here ...
* Steven R. Newcomb
| How is there a recursivity problem?  Can't a set be a set of sets?

Sure, but if role players must always be sets and sets are composed
from assertions you never get to the actual role players because a
recursive infinity of sets containing more sets gets in the way.

Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
ISO SC34/WG3, OASIS GeoLang TC        <URL: http://www.garshol.priv.no >