[sc34wg3] Reference Model to SAM - Mapping Issues and Thoughts

[Lars Marius Garshol]

* Steven R. Newcomb
| 
| In fact, I'd prefer that there be only a single description of the
| SAM.

I think we will only have one: the one that we have now. In addition,
there will be an RM-SAM mapping. 

I understand why you say this, but I feel the SAM document we have
now is hard enough to read as it is, and one expressed solely in terms
of the RM would be much harder. Similarly, the SAM is going to be used
by the XTM deserialization spec (is used, actually), by TMCL, and by
TMQL, and again I think building these on SAM-in-RM rather than on
SAM-as-infoset is going to leave us with three very hard to read
specifications. (And hard to write.)

| I think we can achieve that, but you SAM guys really have to be
| explicit about exactly which subjects the SAM recognizes as
| subjects, [...]

We have a problem here: ISO 13250, XTM 1.0, and the SAM all define
"subject" as the same thing. The RM does not define the term, but
seems to use a consistent definition; however, in talking about the RM
you seem to consistently conflate subjects with the nodes used to
represent them.

I think you should take care not to do that. Talking about RDF is
quite awkward because the distinction between RDF nodes and resources,
though formally there, is not much used in talking about RDF.

| Everything that's not a subject isn't subject to merging; it's just
| a property value.

The SAM is already very explicit about this. Read section 4.
 
| The biggest problem with the SAM today is that it doesn't say which
| information items are properties of subjects, and which are
| subjects. 

It says what merging rules there are. As far as I can tell, that's all
you need to know, isn't it? 

| I think this distinction goes to the heart of what Topic Maps are
| all about, and we really must be explicit about it.  Yes, it either
| involves changing the way the SAM is expressed, or it involves
| having two alternative ways of expressing the SAM (which is much
| harder to do without discrepancies).  We can do it either way.

The roadmap says we'll do it twice. I am not at all keen to change
that. Very much the opposite, in fact.

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