[sc34wg3] SAM 3.4.4 Reification and 3.4.5 Properties

Luis J. Martinez sc34wg3@isotopicmaps.org
15 Apr 2003 23:35:36 -0400


> Basically, the subject world is the world in which you and I live.
> The topic world is the world of topic maps (abstractly conceived), and
> the last layer is that of the SAM representation of topic maps (still
> abstract, but no longer quite as abstract). Every layer represents, or
> models, the layer above it.

> In topic maps, subjects are represented by topics and topics in turn
> are represented by topic items. So subjects in one sense are already
> in the SAM, through the topics that represent them.

> We could of course add subject items to the model, but they would then
> differ completely from all the other item types in the model. They
> would be members of the subject world intruding into a lower level
> that already has a representation of them.

I understand that subjects are in a different layer of abstraction than
the topic maps items and are already represented by topic items. But,
the SAM is responsible to describe how to manage subjects for
merging. That functionality is part of SAM, therefor subjects probably
should be treated as first class objects under the SAM framework.

> That's not to say that your suggestion is wholly wrong. I think for a
> conceptual model that would make sense, but the SAM is a data model
> designed to support interoperability (XTM/HyTM/CXTM) and the
> definition of query and constraint languages.

This exact point is one that I don't completely get. The SAM looks to
me like a implementation design document, very detail. Why does the
SAM has to be so specific? Should this model leave the details up to
implementation, like the locator items? 

I am realizing that what I am looking for if the description of the
application semantics of Topic Maps. I think that the RM/TMM is more
abstract and the SAM is very low level, almost an API. So, is there
something missing in between? 


Luis J. Martinez
email: luisjm@luisjm.com