[Sigia-l] Distributed thesaurus?

[Eric Scheid]

From: Lars Marius Garshol <larsga at garshol.priv.no> (23/9/02 4:32 AM)
>> Although, what you've described above with published subjects means
>> this won't really be possible, unless those canonical sources
>> reflect back locations of the various topic maps that are subscribed
>> to that definition ... 
>
>Either I misunderstand you, or it's the other way around. Typically,
>as you spider around you'd find statements such as 
>
>  "Lars Marius lives in Oslo" (from source A)
>  "Oslo is in Norway" (from source B)
>
>and if sources A and B have referred to the same subject indicator (as
>they are likely to, once the OASIS GeoLang TC gets round to publishing
>the indicator set for UN LOCODE) your spider will know that the
>implicit statement
>
>  "Lars Marius lives in Norway"
>
>is also true

All this implied knowledge is dandy. The problem is that "spidering 
around" can only follow links, and if all these links only point to 
subject indicators and they don't point elsewhere (ie. other topic-maps), 
how will you ever get from source A to source B. 

However ...
>> Perhaps if a topic X in my TM included a reference to not only the
>> canonical X, but also to other X's defined in other TMs.
>
>That is possible, actually. Topics can refer to other topics as their
>subject indicators, and they can have as many subject indicators as
>they want.

That answers the problem of how the spider gets around to other topic 
maps then. Question is, does it treat those links as an entry point to a 
wider topic map, or simply as a subject indicator URI? That is, is it 
expected that a spider will examine the content found at a subject 
indicator URI, realise it is a topic map, and then treat it as a topic 
map (and not just a canonical concept reference)?

I'm guessing it would, if the content of the subject indicator URI 
happens to have a doctype declaring it to be a topic map. Right?

>> If I had a topic map on the subject of (say) IA, in which I connect
>> lots of IA subjects, some|many with the thesaurus terminology of
>> BT/NT/RT ...  does the syntax of connecting A->B support B existing
>> elsewhere (ie. not in my topic map).
>
>Absolutely. That's how it works. You say (using the textual syntax
>known as LTM):
>
>  [ontopia : company = "Ontopia A/S"
>   @"http://psi.ontopia.net/ontopia/#1"]
>
>The URI given above points to the subject indicator. (Sorry about that
>example, it's a bit out of date, and so should be taken with a pinch
>of salt.)

No, this isn't what I mean. Setting aside subject indicators for the 
moment (aka. URIs to a canonical definition of the *concept*), I'm 
talking about connecting two topic nodes within a topic-map space, where 
one of those nodes happens to be in a topic map elsewhere.

For example, in my topic-map I might say "X is related by Y to Z", (where 
both X and Z also have subject indicator URIs, but we'll ignore that for 
the moment). Now, instead of Z being defined *within* my topic-map, it is 
defined in *your* topic-map, and I simply point to it.

>If in a different topic map you then say the same thing a topic map
>processor will know that this is a single subject.

This assumes (1) the processor has knowledge of the other topic map, and 
(2) isn't distracted by dozens of other instantiations in even more topic 
maps, and (3) knows how to select which other references to that subject 
indicator I care about.

Putting it another way, I want to say "if you want to know more about X, 
including a really good topic map I'm not embarrassed to link to, then go 
look at X over at [URI]. Meanwhile, ignore any other references to X you 
might happen to know, as the context/quality/politics is suspect."

e.

______________________________________________________________________
eric at ironclad.net.au                 i r o n c l a d   n e t w o r k s
information architect                      http://www.ironclad.net.au/