Re: [topicmaps-comment] referring to a topic from outside a TM

["H. Holger Rath" <holger.rath@empolis.com>]

"Thomas B. Passin" wrote:
> ... snip ...
>
> {me]
> This would be easy to arrange from a programming point of view.  But
> consider that you use this interface to retrieve a single topic:
> 
> <topic id='tt-flood-portsmouth-1936'>
>     <baseName><baseNameString> The Great Portsmouth
> Flood</baseNameString></basename>
>     <instanceOf><topicRef
>         link:href='http://theSourceOfTheMap.com/#tt-flood-portsmouth-1926'/>
>     </instanceOf>
> </topic>
> 
> It turns out that you do not have the class topic with
> id='tt-flood-portsmouth-1936'.  As a person, you can read the baseNameString
> of the imported topic and perhaps know what it represents (depending on the
> actual name).   But your processor cannot.  It may not even be valid to
> insert this topic into your map, since it references an  unknown topic.
> 
> Even if you could use the topic as is, its associations and occurrences are
> probably what you really want, and they each have their own types,
> superclasses, etc.  You really want a whole subgraph, but how do you know
> what subgraph you want, and how do you ask for that subgraph?
> 
> The interface to get associations by topic id definitely will help, but it's
> not really going to be enough, I think.  That's why I see this subject as
> complicated and important.

The ISO topic maps committee SC34 WG3 talked about this issue last August
and identified it as very important issue to make "global knowledge
interchange" work with topic maps. We named it the "Topic Map Addressing
Scheme (TOMAS)", which could be based on a special URN scheme. But we
have not discussed it in detail because other things have to be finalized
before (e.g., data model).

We know that TOMAS is *really* necessary and that it is not a trivial thing.
But we will address it.

Cheers,
--Holger

-- 
Dr. H. Holger Rath
- Director Research & Development -

empolis * GmbH
Bertelsmann MOHN Media Group
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