[topicmapmail] occurrence abuse ?

[Steve Pepper]

At 13:29 21/08/02 -0400, Sam Hunting wrote:
>Steve Pepper:
> > My position is that there is absolutely nothing wrong with using
> > occurrences for codes, phone numbers, addresses, and the like.
> > In fact, it is eminently sensible and perfectly in line with the
> > "intention" of the "fathers". It is not a question of "laziness"
> > but of pragmatism and the requirements of the application.
>
>Is it your position that this should be the preferred practice for topic
>map applications that use the SAM?

Not at all. As I said, it's a question of the application requirements
and the intention of the topic map author. If there is a defensible
reason for creating topics for such things, fine. However, the advice
I would give would be to "err on the side of caution", i.e. use
occurrences unless you have a good reason not to.

>I'd be curious to see how, in your view, RM "moderates" TMPM4 in this regard.

It's mostly a matter of terminology. TMPM4 talked in terms of T-nodes
and A-nodes. Whether it was intentional or not (on the part of the
authors of TMPM4), people tended to equate T-nodes with topics. In the
RM there is only one node-type, so that tendency is no longer
encouraged to the same extent.

>Steve Pepper:
> > Put another way: A topic is a nexus for information about a given
> > subject. If you know that you are only going to have one piece of
> > information for topics of a certain type (say, phone numbers), then
> > it's worth considering whether you can get by without creating
> > topics for those things at all.
>
>What you you mean, "create a topic"?

Compare the following examples (in LTM syntax, for brevity):

(1)  [ontopia = "Ontopia"]
        {ontopia, phone, [[+47 23233080]]}

(2)  [ontopia = "Ontopia"]
      [ontopias-phone-number = "+47 23233080"]
        has-phone-number( ontopia, ontopias-phone-number )

In (1) there is just one topic - [ontopia] - and we express the phone number
as an occurrence of that topic (curly braces are the notation for occurrences
in LTM).

In (2) there are two topics - [ontopia] and [ontopias-phone-number] - and
we express the relationship between the two using an association (ordinary
parens are the notation for associations in LTM).

Using approach (2) we had to "create a topic" for the phone number in
order to capture the information.

I think this should explain what I mean by "create a topic".

Steve

--
Steve Pepper, Chief Executive Officer <pepper@ontopia.net>
Convenor, ISO/IEC JTC1/SC34/WG3  Editor, XTM (XML Topic Maps)
Ontopia AS, Waldemar Thranes gt. 98, N-0175 Oslo, Norway.
http://www.ontopia.net/ phone: +47-23233080 GSM: +47-90827246