[topicmapmail] external resources reifying

[Jan Algermissen]

> Olivier Lamborelle wrote:
> 
> Jan Algermissen wrote
> 
> > I really don't see why this matters at all for you, why not use the syntax as intended? What
> > are the problems you have?
> >
> >
> > Or do you write your own engine, afer all?
> >
> My main concern was that if  topics using the document as occurrence can not refer to the topic reifying the document, it means the address is
> duplicated troughout the topic map, each time a topic use it as occurrence. And there will be no direct link between the occurence and the
> attributes of the occurence, except through a search like "is there any topic in the TM whose subject identity is the same as the resourceRef of
> this topic occurence ?".



Ah, now I see what you mean. It is exactly this kind of problem that the Topic Maps
Reference Model [1] solves completely by providing exactly one single surrogate for each
subject. In a Reference Model conforming application, all information about every
subject will be directly available from a single point.The rpoblem you mention simply
does not exist.

Applications that implement the 'Standard Application Model' (SAM) suffer from the
problem you describe and need to provide proprietary indexes that make the information
you are concerned with directly available. As an end-user you propably won't notice this,
but I think it is worth to point out that the connection you request is not explicitly
a part of the Standard Application (Data) Model but needs to be computed (with exactly
the kind of query you wrote down: "is there any topic in the TM whose subject identity
is the same as the resourceRef of this topic occurence ?".).

I have personally never understood why nearly nobody has ever been concerned with this
particular weakness of the SAM.

Jan


[1] http://www.isotopicmaps.org/tmrm/



> 
> > Be patient, it takes some time and practice. Feel free to ask more.
> >
> Thanks.. I'll work further and wait for new fresh issues...
> 
> Olivier.

-- 
Jan Algermissen                           http://www.topicmapping.com
Consultant & Programmer	                  http://www.gooseworks.org