[topicmapmail] Merging of Distributed Topic Maps based on the Subject Identity Measure (SIM) Approach

[Lars Marius Garshol]

* Bernard Vatant
| 
| Amazingly, I've thought a lot lately about typing (or
| classification) as a recommended first step in identification
| process, for both conceptual and technical reasons. I'm happy to see
| you both ploughing in that direction, too. 

I think it's really a natural approach, given that the most telling
piece of information about any topic is really its type.

| In fact, it was a hot and never solved debate, in PubSubj TC, to
| figure out the level of commitment implied by the use of identifying
| properties, whatever their type : name, PSI or any other property
| fit for establishing identity, exact or fuzzy. This is an important
| aspect of this issue - not the only one.

Yep.
 
| So, I wonder if Lars Marius would go as far as rephrasing his above
| paragraph, replacing "name" by "subject indicator", as :
| 
| "If the subject indicators are the same but the types are disjoint,
| then you can safely ignore the subject indicators."
| 
| IOW, would you recommend (as a best practice at least) that the
| merging constraint carried by equality of subject indicators could
| be relaxed when classes are implicitly or formally disjoint (like
| person and place).

Actually, TMDM is very explicit on this: you can't ignore subject
indicators.  Full stop.  So I would say that this should be treated as
a conflict.
 
| OTOH, should not PSIs include somehow the declaration of the class
| of the identified subject, in such a way that use of the PSI for a
| topic in an explicitly disjoint class would be considered as an
| error?

That's a good question, and I think the answer depends on the subject
you are creating a PSI for. I can imagine situations where you are
defining PSIs quite loosely, perhaps for use in a thesaurus or similar
classification system, where you don't want to specify the type. But I
agree that in general you do want to specify it, and that in these
cases it would be highly questionable to use the PSI and type it with
a disjoint type.

Whether we could consider this an error automatically I'm very much
uncertain of, since using the PSI doesn't in itself cause anything to
happen in your local topic map. Your TM system would need to know what
type was claimed for the topic in the PSI, that you'd assigned it a
different type, and that the two were disjoint in order for an error
to occur. (You may have been assuming this, for all I know; I just
want to be clear.)
 
| Of course, this goes into moving ground, because it's clearly
| questioning the "absolute" nature of subject identity, that is
| supposed to be carried by the subject indicator in the TM paradigm.

Yes.

-- 
Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
GSM: +47 98 21 55 50                  <URL: http://www.garshol.priv.no >