[topicmapmail] multiple Source Locators

[Kal Ahmed]

On Mon, 2004-08-30 at 18:35, Jan Algermissen wrote:
> Stefan Lischke wrote:
> 
> > I think "multiple subject locators" is solving alot of problems, but  on
> > the other hand maybe creates new stuff to think about.
> > 
> > What are you thinking about this issue?
> 
> Stefan,
> 
> I think, that it is a question of DECIDING what the MEANING of a subject locator
> is. If This meaning allows multiple subject locators to address the same 'thing',
> then, yes, we should have a set of them instead of a single one.
> 
> Beware that this also depends on the technology that you deploy topic maps on.
> For example, when used with the Web/URIs, an address can NEVER address a piece
> of data, just abstractions of it, because URIs address resources (abstractions), not
> representations (data). That is an architectural property of the Web and it
> IMHO significantly affects the semantics of 'subject locator'.
> 

I agree. However, allowing multiple subject locators doesn't address
this issue at all - it just creates more confusion by allowing a topic
to have subject locators that address multiple abstractions (and
possibly even multiple data items). IMO, the old heuristic of zero or
one subject locator per subject is a lot easier to understand,
communicate and design around.

> (To add to the confusion: I personally have dropped the use of subject locators
> alltogether in projects that use Topic Maps and HTTP and instead only use
> subject indicators. This creatly improves interoperability with the 
> technology (browsers) and also with RDF.)
> 

I'm intrigued. As I understand it, in RDF you can use URIs as the
equivalent of TM's subject locators as they are currently defined (as in
the world famous "http://.... author 'Ora Lassila'". Does that mean that
you restrict your RDF models to only use the equivalent of subject
indicators ? 

Cheers,

Kal

-- 
Kal Ahmed <kal@techquila.com>
techquila