[sc34wg3] RM4TM 2 roleplayers and merging

Marc de Graauw sc34wg3@isotopicmaps.org
Sat, 23 Nov 2002 18:35:23 +0100

RM4TM requires at least two r-nodes in an assertion. The r-nodes can be
x-endpoints in Cx arcs too. And TM Applications can confer SIDP values on
these nodes based on their situations. Couldn't this lead to well-formedness
violations when merging?

When we have an association with two r-nodes, R1 and R2, each of which have
have two SIDP's which I shall call S1 and S1, and they have the following
values conferred on their SIDP's because of their situatedness and the rules
of the governing TM Application:

    S1: 1
    S2: 1

    S1: 2
    S2: 2

If the governing TM Application would require nodes with the same S1 or S2 to
be merged, this would constitute a well-formed and fully merged TM graph
(assuming nodes and arcs not mentioned are also well-formed and fully merged).

Now when we merge with a second Topic Map with a node y which serves as the x
endpoint in one or more Cx arcs, and which has the following SIDP values:

    S1: 1
    S2: 2

The merging process would require R1 and R2 to be merged, yielding an
assertion with only one r-node, and thus the resulting TM graph would not be

So is it possible that two Topic Maps which each are well-formed and fully
merged merge to a Topic Map which is no longer well-formed? Or should TM
Applications forbid this, and if so, how?