[xtm-wg] Re: Feedback on Processing Requirements F3.2

[Steve Pepper <pepper@ontopia.net>]

At 10:34 08/02/01 -0500, Luis J. Martinez wrote:
>[Graham wrote:]
> > the intent is that is the topic IS a proxy for a resource, using resource
> > ref - that it cant play the role of class in this assoc.
>
> > The intent I think is correct the wording is not strong enough.
>
>...
>
>I don't get this. So, there a difference between a topic with an
>addressable subject and a topic with an addressable subject where the
>topic is just a proxy to a resource. There is a difference in the syntax,
>but there is not difference in the object model. Is there? Besides,
>that is not what the spec says in F3.2.
>
>I think I understand you, but I don't want to pretend. Can you explain
>this to me?

Luis, I think you are misunderstanding Graham. It seems to me that
you are conflating resources as addressable subjects with resources
as subject indicators. In your original note you wrote:

At 22:02 07/02/01 -0500, you wrote:

>F.3.2 Equivalence of <instanceOf> and <association> contains that
>is an XTM Error when:
>The Class role is played by a topic with an addressable subject. 
>
>I interpret that a topic with an addressable subject is considered a
>concrete topic which can not play the abstract Class role in a
>Class-Instance association.

I don't know what you mean by "concrete" here, but, yes, what we
are saying is that an addressable subject cannot, by definition,
play the role of class. You then go on to say:

>I don't find this necessary. A topic representing the Human concept
>can have an addressable subject in a comprehensive ontology. But, that
>does prevent the topic being used as an abstract meaning in a topic
>map.

A topic that reifies the concept "Human" can have a *subject indicator*
that is a resource (i.e. an addresable information resource) in a
comprehensive ontology.

That is different from what you say. Any topic whose addressable
subject is a resource in an ontology reifies *the subject that IS
that resource*, not the thing described or otherwise indicated by
the resource.

If, in a <subjectIdentity> element, you address the Library of 
Congress Catalog entry for "Human" using a subjectIndicatorRef, you
are reifying the concept "Human".

If you address the same resource using a resourceRef, you are
reifying the entry "Human" in the LCC.

>So, I think that a topic can play the role of Class in a
>Class-Instance association regardless if it contains a addressable
>subject or not.

I hope you now agree that a topic that reifies a resource (in other
words, a topic with an addressable subject) cannot, by definition,
play the role of class.

Steve

--
Steve Pepper, Chief Technology Officer <pepper@ontopia.net>
Convenor, ISO/IEC JTC1/SC34/WG3  Editor, XTM (XML Topic Maps)
Ontopia AS, Maridalsveien 99B, N-0461 Oslo, Norway.
http://www.ontopia.net/  phone: +47-22805465  GSM: +47-90827246


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