[sc34wg3] Documenting merging rules in TMDM

Steve Pepper sc34wg3@isotopicmaps.org
Sat, 13 Mar 2004 14:07:59 +0100

I omitted to draw your attention to the fact that the
Topic Maps Data Model was recently approved as a CD by
National Bodies. Congratulations to everyone involved!

There were some useful comments from Japan and the US which
we will have to consider. I would like to address one of
them here.

The US National Body considers it to be a "severe defect"
that there is no means of "documenting an extension to
the data model for additional merging rules" in the TMDM.

While I disagree on the severity of this "defect", I agree
that there might be a real user requirement here that we
should try to satisfy.

In order to see how the requirement might be satisfied, it
would be useful to have a representative selection of the
kind of merging rules the US NB is talking about. Quite
apart from anything else, this would ensure that we have
the same understanding of the requirement.

I would therefore urge everyone, and the US National Body
in particular, to put forward examples of the kind of
merging rules we need to be able to express, so that we
have something tangible to discuss in Amsterdam.

To get the ball rolling, I will propose a couple of simple
ones myself:

R1  Merge topics that have the same name in the same scope.

R2  Merge topics that have identical occurrences of type
    'home page'.

R3  Merge topics of type 'person' that have identical
    occurrences of type 'email address'.

R4  Merge topics of type 'company' that have one or more
    names in common are 'located in' the same 'country'.

R5  Merge topics that play the role of 'parent' with respect
    to the same topic.

Some questions:

Q1. Are these examples of the kind of thing the US NB is
    thinking of?

Q2. How representative are they?

Q3. What other examples can you come up with?

Q4. What would be an example of the most complicated kind
    of merging rule you think the standard should be able
    to document?

Q5. Should it be possible to document the rules in a
    formal, machine-processable manner?

Q6. Should it be possible to express rules using criteria
    that are not present in the topic map to which the
    rules apply? (In my examples, all rules are expressed
    in terms of constructs in the topic map in question.)

Q7. Should the merging rules cover the merging of anything
    other than topics?

If we get answers to these questions, and a representative
set of merging rules, we might be able to resolve this issue
in Amsterdam.

Best regards,


Steve Pepper <pepper@ontopia.net>
Chief Strategy Officer, Ontopia
Convenor, ISO/IEC JTC 1/SC 34/WG 3
Editor, XTM (XML Topic Maps 1.0)