[topicmapmail] PSIs?

[Murray Altheim]

Lars Marius Garshol wrote:
 > * Murray Altheim
 > |
 > | Okay, I can certainly state that the "PSI" URLs are the ones to use,
 > | since they point to the XTM document.
 >
 > That would help. It would mean that you don't conform to the OASIS
 > recommendations, though.

I don't follow. If I publish a spec that includes an XTM document, and
use its IDs as the PSIs (i.e., make it clear that they are the PSI URLs),
but also have subject identity with the URLs found in the XSD spec,
what's wrong with that? It's not leaving any ambiguity if the spec
says use the ones I have created. I'm very uncomfortable defining
PSIs that happen to have a base URL in the W3C namespace/domain, and
there might even be legal barriers to me doing so. I can, however,
publish something within my own namespace/domain and claim subject
identity with W3C/XSD, which is what I've done.

 > | If you've included that topic map (datatypes.xtm) in your system, it
 > | shouldn't matter, eh?
 >
 > I don't think it's appropriate to assume that people must do that.

They don't need to, it's just an option.

 > | The PSI in datatypes.xtm has subject identity with the XSD sID.
 >
 > Unless it also has the PSI URLs in there you'll have to load the file
 > over HTTP to get the equivalence declarations between the PSI and
 > "sID" URLs. That won't work in all cases, of course.

They wouldn't in order to use the PSI set, it's just that if they
did, they'd have subject identity with any other PSI that used the
XSD definitions, which is whole point of my having them (and to me,
the whole point of doing this in topic maps).

 > * Lars Marius Garshol
 > |
 > | Why not make the <subjectIndicatorRef/> in the XTM document point to
 > | the URI derived from the XSD Recommendation? Then you have no loop,
 > | and everything should be fine. You can have a single URI and simplify
 > | your document quite a bit.
 >
 > * Murray Altheim
 > |
 > | Well, that's how it actually is right now.
 >
 > In that case, why not just ignore the "PSI" URLs and only use the
 > "sID" ones? Then you only have a single set of URIs and all is well.

Because, as I mentioned above, I want merging behaviour with anyone
else's topics that match the XSD subjects.

 > | I wouldn't want to do that, since the XSD spec is *semantically*
 > | the canonical definition for what these PSIs mean.
 >
 > That makes sense to me.
 >
 > | I think all this is resolved by (as you say) simply stating that
 > | within topic map environments, the "PSIs" as listed are the ones to
 > | use. The "sID" are noted as being subject identifiers within the
 > | topic map and as links to definitions, but shouldn't be used (but
 > | could be if the datatypes.xtm is brought into a system of maps).
 >
 > Well, the whole point of creating published subjects is to define a
 > *single* URI that identifies each subject. This means defining two for
 > every single one. Surely you agree that that's not good?

There is only one single PSI identifier for each subject. I don't
see any harm in including the XSD URL as a binding point as well,
so long as my documentation (both in the spec and in the comments
of the XTM document) make it clear which to use as the PSI.

Murray

......................................................................
Murray Altheim                  <http://kmi.open.ac.uk/people/murray/>
Knowledge Media Institute
The Open University, Milton Keynes, Bucks, MK7 6AA, UK

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