[topicmapmail] Identities and names (WAS - A somewhat new topic maps format)

[Bernard Vatant]

Hello Daniel

> In response to your main message - yes, very important.

Seems that everyone agrees on that today. Good thing. More below.

> In response to your PS2 - you say "Or maybe the other way round ??"

Note that was written while re-reading Alice Through the Looking Glass, in
the excellent version annotated by Martin Gardner. So ... It's *not* My Own
Invention ... [1]

> I would say definitely the other way round.

Makes sense ...

> "Bunzilla" is the (or a) name of Murray's rabbit
> "Bunzilla" is also the (or a) name of Peter's rabbit
> "http://www.altheim.com/bunny/#bid0537" is what the name "Bunzilla" is
> called in the scope of Murray's topic map of bunny names and the subject
> indicator formalism.

Actually, Murray's page is not a proper topic map IMO, but a PSI set ...

> "X is called 'A'" is synonymous with "'A' is a name of X"

I guess Lewis Carroll would have bought that one :)

> So you can also say
> "http://www.altheim.com/bunny/#bid0537" is a name of the name
> "Bunzilla".

Right. But as Murray states in his answer, this name has some declared
identification context and mechanism (or protocol), so it's not exactly
*any* kind of name ... See below.

> Strictly, we know that in Topic Map terminology,
> "http://www.altheim.com/bunny/#bid0537" is the subject indicator for the
> topic whose subject is the name "Bunzilla".

Well, you should update your terminology here, to agree with most recent
both SAM and PubSubj TC specifications:
"http://www.altheim.com/bunny/#bid0537" (the URI) is the subject
identifier. The subject indicator is whatever human-readable resource you
get when pulling this handle through http protocol ... can of worms ...

> But in ordinary language, a name serves precisely the function that a
> subject indicator does in the topic maps formalism - it indicates to the
> hearer/reader what subject is being spoken of. A topic maps subject
> indicator is therefore a particular kind of name.

There again, it seems you confuse subject identifier and subject indicator.

The subject identifier is indeed a name, and as such it can be used for
identification in a clearly defined context, and through a clearly defined
protocol : for example the context of a Topic Map application, the protocol
being interpretation of subjectIndicatorReference by a TM engine for
merging topics.

Of course, the subject identifier barely indicates the subject to the
(human) reader. Without leading to a subject indicator, the URI
"http://www.altheim.com/bunny/#bid0537" does not say much. But note - this
is an overlooked thing - that getting to whatever subject indicator you get
through this URI is just another use of the same name for identification
purpose, but in another context (human use) and another protocol (getting a
human-readable resource through http).

So, in the notion of PSI, we have figured two uses of the name-identifier
in two different contexts and through two different protocols (a
computer-only one, and a computer-human interaction one). Now, the same
subject identifier could be used also in other contexts and through other
protocols as well - for example in ontologies, but in a way that remains to
be defined. And indeed, figuring out how subject identifiers can be used
across different contexts and through different protocols is the crucial
interoperability challenge we face now. It goes beyond the "Web identity
crisis" about URIs, or this crisis is just one aspect of it, and in fact it
goes beyond PSIs, because PSIs are linked to this very specific protocol of
dereferencing URIs through http for human consumption.

Bernard

[1] For the (hopefully improbable) reader still unaware of Lewis Carroll's
pionneering work in those difficult matters back in 1871, when the oldest
and wisest of us all were barely born, this is a *must* background reading:
"Alice Through the Looking Glass, Chapter VIII : It's My Own Invention" .
The "Annotated Alice" by Martin Gardner should still be available  although
it was published in the 60's - Penguin Books - ISBN 0 14 00 1387 3.

Bernard Vatant
Senior Consultant
Knowledge Engineering
Mondeca - www.mondeca.com
bernard.vatant@mondeca.com