[topicmapmail] inheritance question

[Graham Moore]

Hi Max,=20

In short nothing you do in the XTM (short of actually connecting the
instances to B will connect them to B). =20

This is because XTM is an interchange syntax and doesn't DO anything =
(much
at least). However, implementations and query languages based on XTM =
could
provide you with the features you require.

It depends what you are trying to say, if you are trying to say that all
instances of A are instances of B then using the class-subclass =
relationship
(via PSIs) will help you do this. It is of course dependent on using a =
TM
implementation that supports class-subclass in a transitive fashion.

In this case you would make A a subclass of B and you would be done. =
Every
time you created an instance of A it would also be an instance of B.

However if you are looking to express something other than instance-ness
then you need to do something in terms of inferencing. i.e. every topic =
that
is an instance of A is also an employee at MIT. And at the moment
interpretation of these kinds of rules will be different across TM
implementations.

I hope this helps,=20

Graham

----------------------------------------------------------------
Graham Moore, Ontopian            moore@ontopia.net
GSM: +47 926 82 437           http://www.ontopia.net


-----Original Message-----
From: topicmapmail-admin@infoloom.com
[mailto:topicmapmail-admin@infoloom.com] On Behalf Of Max Voskob
Sent: 30 September 2003 04:17
To: Topicmapmail

Dear XTM experts,

I have a class A and 225 topics that are instances of this class.
If I create an association between class A and another class (say B) =
then
will this asscociation apply to all the instances of class A?

If not, is there any other shorcut to associate class B with all the =
topics
that are instances of class A? I don't want to create an association =
with
225 members and I don't want to remember about adding new members to =
this
association when I create a new instance of class A.

Thanx for your help!

Max Voskob






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