[sc34wg3] Scope, again

Martin Bryan sc34wg3@isotopicmaps.org
Thu, 28 Nov 2002 09:01:31 -0000


Ok, I'll bite :-) Some comments on carefully selected (and taken out of
context) comments in your response:

>                       topic-name
>                          (T)
>             topic         |        name
>               (R)         |         (R)
>                |          |          |
>                |          |          |
>    (x)--------(C)--------(A)--------(C)--------(x)
>  Paris              Paris has name            "Parijs"
>                        "Parijs"
> (I use Paris to denote the city and the quoted "Parijs" to denote the

The situation with the Dutch term is straightforward, but the
English/French/... name gives us an entirely different set of problems.
Instead of:

>                      topic-scope
>                          (T)
>              topic        |        scope
>               (R)         |         (R)
>                |          |          |
>                |          |          |
>    (A)--------(C)--------(A)--------(C)--------(x)
>  Paris has name      Paris has name          Dutch
>     "Parijs"       "Parijs" in Dutch
>  (A is the assertion
>      above)

we either have a whole set of assertions for single languages, or we need to
create a set in place of the final (x). At what level in the models would
responsibility for a) defining the set, or b) identifying that a name is
used by more than one language, reside?

[NB: The Paris case is a good example of what happens is practice. If a
specific language does not have its own version of a place name then the one
applied by the natives is adopted. So the fact that there is no language
entry for Tamil in the topic map name list for the Paris topic does not mean
that Tamil does not recognize Paris, only that it uses the default name. It
is for this reason that I am very much against treating languages as scopes,
which restrict the rules you can apply to the selection of names.]

> So I would strongly object to using scope as a
> true catchall way to state anything one wants about relationships.
> What this leads to is the question whether scope is truly a general
> to say things about assertions, or, on the contrary, a mechanism to say
> specific things about assertions, namely the circumstances in which we
> assertions to be valid or not.

How true: scope should not be used for differentiating languages - it should
be restricted to the identification of domains in which topics apply.

> From 'Logic, Language and Meaning', L.T.F. Gamut, London 1991, ISBN
> 0-226-28086-1, loosely quoted from page 13:
> In logic, propositions are traditionally supposed to be independent of
> and place, so that they may be said to be unconditionally either true or
> false. Examples:
> (1) Knowledge implies belief.
> (2) 5 + 7 = 12

For reasons why I doutbt (2) see
http://www.sgml.u-net.com/maths-conundrum.doc :-)

> Now scope should be used to do exactly this: adding contexts in which
> assertions are valid.

Yes. But how can you say that "Language of the name Parijs is Dutch" in any
way changes the validity of the assertion that "Paris has the name Parijs"?
[Note that your example assertion does not match the scope statement, which
would assign Dutch as the language of the name, and not add anything at all
to the topic itself (the scope would only qualify the name, not the topic).]

> Context - and scope - is for things we do
> not want to make explicit assertions about.

Or create specific associations for!

> So scope to me is just a way to make a specific kind of assertion: an
> assertion which limits the validity of another assertion.

This is not how I would phrase it. I would suggest that "scope identifies
those domains in which the assertion is known to be valid: if no scope is
stated then the assertion is valid in any domain". Note the subtle
difference due to the fact that something can be known to be valid in one
domain, and yet be valid in another domain without the topic map author
being aware of that fact.

> If different
> people use scope in different ways because the SAM lets them, that is not
> going to help interoperability.

But restricting the ways in which scope can be applied will not help the
acceptance of topic maps. We need to be very careful not to forbid any
situation in which the use of scope is relevant.