[sc34wg3] Draft Reference Model

Bernard Vatant sc34wg3@isotopicmaps.org
Fri, 15 Nov 2002 18:04:34 +0100

Some first comments on RM4TM

1. General comments on the "topic map graph".

The definitions are much clearer than in previous version. I think it is now possible to
propose a quite accurate rendition in a mathematical language that graph theory people
will understand (if not agree with). Although it seems to me now quite clear that RM4TM is
*not* likely to be mapped on the hypergraph model that we (P.Auillans, P.Ossona de Mendes,
B.Vatant) have presented a few months ago, at first sight the hypergraph model could be
mapped to some (more constrained) subclass of RM4TM.
My concern is also to know if an axiomatization of RM4TM as a mathematical graph will meet
a documented and well-known type of graph, or some weird form that nobody has cared to
study yet.

I will investigate on all that, and could report in Baltimore if I am given the
opportunity to do it.

2. Subject Identity Discriminating Properties (SIDPs) vs Other Properties (OPs)

It is, if I get it well, the coolest thing in all the proposal, and the way to settle all
the identity-names-scope debate.

3. Minor various comments

>   Well-formed node Case 3 ("a-node")
>   The node serves as the A endpoint of two or more AC arcs.

Why "two or more"? There are many cases of assertions with a single role type (take
"sibling" for example)
Is this case ruled out by the model? I would suggest "one or more" here

>   Well-formed node Case 4 ("c-node")
>   The node serves as the C endpoint of a single CR arc.

That means role type is mandatory. I'm very happy with that, vs <roleSpec> being optional
in XTM 1.0.
OTOH assertion type is still optional ...

>   Well-formed node Case 3 ("a-node")
>   The node may or may not serve as the A endpoint of one AT arc.

I'm curious about the rationale making role type mandatory and assertion type optional.
(BTW both are mandatory in Mondeca ITM)

>   Subjects of Case 6 nodes

> The subject of a t-node is a class of relationship,
> including the roles that can be played in instances of the class,
> and the values that are conferred on the properties of role players
> by virtue of their situations as players of specific roles in instances of the class.

Those are "assertionPattern-role-rolePlayerConstraints" of the Draft Reference Model?
Have they been put out of the graph? Or does RM4TM leaves free the way of expressing those

>   Semantics of role playing
>   No multiple role players of a single role type
> Note 21:  However, the subject of a role player can be a group of subjects ...

I'm uneasy with that. Having several subjects playing the same role in an assertion looks
to me more natural than having to create first a subject which is a group of subjects ...
If I think I am linked to my children by a "father-child" relationship, have I to consider
them first as a group? Or if I don't want that, split this assertion is so many assertions
that I have children.

I would like the rationale of Note 21 to be expanded. On this father-child relationship,
for example.

Well, that's it for today I guess. More to come certainly


Bernard Vatant
Consultant - Mondeca
Chair - OASIS TM PubSubj Technical Committee

----- Message d'origine -----
De : "Steven R. Newcomb" <srn@coolheads.com>
À : <sc34wg3@isotopicmaps.org>
Envoyé : jeudi 14 novembre 2002 00:22
Objet : [sc34wg3] Draft Reference Model

> A draft of the long-awaited Reference Model is now
> available at http://www.isotopicmaps.org/rm4tm/.
> I would like to thank:
> * Vicky Newcomb, my partner in everything, and no less
>   so than usual in this.  She did the HTML rendition
>   and the graphics.  (Everyone has already seen the
>   graphics).
> * Sam Hunting and Jan Algermissen, without whose
>   essential intellectual and spiritual contributions,
>   and many months of constant hard work, this draft
>   would not exist.
> * Martin Bryan, who made essential improvements to this
>   draft.
> * Michel Biezunski, whose constant monitoring of the
>   progress of this draft, and the insights and
>   criticisms he contributed to the development process
>   of the Reference Model, were invaluable.  (Also, we
>   should all bear in mind that, without Michel's
>   incredible and sometimes lonely persistence over many
>   years, none of this Topic Map stuff would be
>   happening today.)
> -- Steve
> Steven R. Newcomb, Consultant
> srn@coolheads.com
> Coolheads Consulting
> http://www.coolheads.com
> voice: +1 972 359 8160
> fax:   +1 972 359 0270
> 1527 Northaven Drive
> Allen, Texas 75002-1648 USA
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