[sc34wg3] Draft Reference Model

Sam Hunting sc34wg3@isotopicmaps.org
Fri, 22 Nov 2002 21:38:47 -0500 (EST)

On Mon, 18 Nov 2002, Jan Algermissen wrote:

> Graham Moore wrote:
> > 
> > One other quikie...
> > 
> > In the RM is there a built in type 'Set'? Or are role player nodes always Sets?
> Graham,
> a quick answer.
> No, in the RM there is no notion of setness, all there is, is the
> constraint that there may not be more than one player for a single
> role.
> This constraint ensures that any group of subjects that play the same
> role in a relationship (as it understood in the world outside the
> graph) will be represented by a single node in the graph
> representation. This is important, since this set is a subject (the
> set of players of a certain role in a certain assertion) and so there
> must be a node for it.
> For example, if we did not have that node, how would we reason about
> (=make assertions about) the cardinality of that set, in order to
> validate any cardinality constraints imposed on the number of players
> of a certain role.

For example, we might which to make an assertion about (=constrain for
some application) a set of scope components (like the drawing I put on the
board in Montreal).


Sam Hunting
eTopicality, Inc.

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