Re: Another round of subject identity crisis c.2011

Hi Andrew,

[...]
> Hmmm.... I understand what you're saying, but I'm not sure I get
> it.  Maybe it's just personal perspective warpage going on here, but
> in this case, why is the extra level of redirection necessary?  This
> is probably old ground, but why wouldn't you just put the metadata
> on the thing itself ant treat the thing as a topic?

Let's try another, concrete example. :) Imagine I have created a PSI
for the city "Bremen":

    http://psi.example.org/Bremen - "Freie Hansestadt Bremen".


Now I like to attach information to the PSI, like when I created it,
if it is stable etc. If I'd state:

    http://psi.example.org/Bremen
        created-by(Lars-Heuer);
        psi:status(psi:experimental);
        created-at(2011-03-09);
    .

I'd effectively say that the *city* Bremen was created by me and has
an experimental status. That's obviously wrong.

The usage of a subject locator

    = http://psi.example.org/Bremen
        created-by(Lars-Heuer);
        psi:status(psi:experimental);
        created-at(2011-03-09);
    .

makes clear that the statements created-by etc. refer to the resource
and not to the subject "Bremen".

I have two topics which describe different aspects of the IRI
<http://psi.example.org/Bremen> and the topics wouldn't automatically
merge (since one uses the address as subject identifier and the other
as subject locator).

[...]
> If I want to make type-based statements about the content from said
> resource, I do something like this:

> dublin = http://en.wikipedia.org/wiki/Dublin
>         isa city;
>         population: 506211;
>         ... ;
>         .

Here you're saying that the *webpage* is an instance of "city" and has
a population. I think you want to use a subject identifier here:


  dublin http://en.wikipedia.org/wiki/Dublin
         isa city;
         population: 506211;
         ... ;
         .

would say: The subject described by
<http://en.wikipedia.org/wiki/Dublin> is an instance of "city" and has
a population of ... .

> What you're effectively saying above is that there's no way to
> publish networked topic maps, right?  If both locators and
> identifiers are treated as opaque, this must be true.

I haven't said that, I hope. Why shouldn't it possible to publish
publish networked topic maps?

Let's assume you have information about Dublin published at
<http://psi.example.andrew/Dublin>.

I have published information about Bremen at
<http://psi.example.lars/Bremen>.

A bus tour operator uses the PSIs in it topic map and publishes
somewhere the following topic map:

    distance(location: <http://psi.example.andrew/Dublin>,
             location: <http://psi.example.lars/Bremen>,
             km: km-1300)

    km-1300 - "1300".

I an agent reads the topic map, it can easily hop to your server and
receive more information about Dublin and to my server to fetch more
information about Bremen (assuming that we both are smart guys which
deliver not rubbish HTML but topic maps if we're asked for the right
media type).

[...]
> Therefore, if subject locators are addressable, and, by definition,
> they're subjects - but only until the address resolution takes
> place.  Once you have this, you have a "something".  In my view, the
> only way networked topic maps will work is if you can attempt to
> introspect that something, at some level,

Yes that's possible.

[...]
> t1 isa =http://psi.example.org/v1/mytype .

> is that legal?

Yes, that would be legal. If that's useful is another question.


[...]

Sorry, I have to stop here. I'll try to come back to the rest of your
e-mail this evening.


Best regards,
Lars
-- 
Semagia 
<http://www.semagia.com>

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