[topicmapmail] Are Facets Really Simple After All?

[Murray Altheim]

Kal Ahmed wrote:
> On Mon, 2003-12-01 at 00:24, Murray Altheim wrote:
[...]
>>But by the same token, I think simply a pragmatic analysis of
>>what you're proposing should suggest some best practices. By that
>>I mean, a simple reading in English of what you're suggesting.
>>I can understand that an occurrence of the Topic "Paris, France"
>>might be a latitude/longitude for Paris, an important date in
>>its history, a photograph of the Champs Elysees, etc. The standard
>>rightfully doesn't constrain any of this kind of thing; it would
>>make Topic Maps much less interesting and valuable. But I can't
>>imagine that a "correct" occurrence of the Paris Topic would be
>>"2003-11-23T11:34:55", "245,190", or "#bce033" (i.e., the creation
>>date of the Topic in my application, the location of the Topic
>>node in my TouchGraph visualization, or the colour of the displayed
>>node, resp.). That just isn't right. Now, if I never planned to
>>share that Topic Map with anyone, hell, I can do what I like*),
>>but it doesn't *to me* express a correct interpretation of the
>>standard. Even in the inimitable vagueness of its definition of
>>"occurrence", a property of a Topic and an occurrence of a
>>Topic simply aren't the same thing. Certainly not semantically.
> 
> In that case we agree. But you talk here of meta data for the topic (as
> opposed to meta data regarding the subject) for the first time. I was
> simply pointing out that subject meta data is valid "information
> relevant to the subject". I would expect topic meta data to be expressed
> as occurrences of another topic whose subject is the topic construct
> that you are making the assertions about. 

No, not the first time. The first message of the thread I started
on facets outlined two forms, Model A (the "RDF" model) and Model
T (the "facet" model). Metadata about a topic is what I've been
talking about all along. That's what RDF is: metadata about a
single thing, a simple triple. The differentiation between "metadata
about a Topic" and "metadata about a subject" I'm not making. I'm
going to have to answer Bernard, but in my first glance he mentioned
that Topics are binding points. I agree with that. The triples in
Model A are properties attached to the Topic. I consider those
different than occurrences attached to the Topic. Occurrences are
a specialized Association in the model that have their own special
semantics and a special syntax in XTM, the <occurrence> element. We
never created a <facet> element, nor did we a <property> element.

Murray

......................................................................
Murray Altheim                    http://kmi.open.ac.uk/people/murray/
Knowledge Media Institute
The Open University, Milton Keynes, Bucks, MK7 6AA, UK               .

   "Mr Bush, you have to admit it's a pretty remarkable thing for a
    man just to go to a hotel room door and open it and have a woman
    standing there and have sex with her," said Marshall Davis Brown,
    lawyer for Sharon Bush. "It was very unusual," Bush said.
    http://www.nzherald.co.nz/storydisplay.cfm?storyID=3536318