[sc34wg3] XTM 1.1 issues: reification

Patrick Durusau sc34wg3@isotopicmaps.org
Tue, 06 Dec 2005 17:41:05 -0500


Responding to only part of your excellent post on the XTM 1.1 issues:

>--- Reification
>The reification processing in the current XTM draft is very heavy,
>basically because reification is explicit in the model, but not in the
>syntax, so you have to wait until the entire document is read before
>joining up the reification connections.
>The solution is to make it explicit in the syntax. We thought of four
>  1) -reifier- attribute on anything that can be reified
>     cut ID from everything, except <topic>
>     bad: have to add everywhere, not consistent with general XTM 1.0
>          syntax design
>  2) <reifier> sub-element on anything that can be reified with
>     <topicRef> inside
>      bad: have to add everywhere
>           very intrusive
>           becomes very ugly indeed inside <topicMap>
>  3) -reifies- attribute on <topic>
>     bad: not consistent with general XTM 1.0 syntax design
>  4) <reifies> sub-element on <subjectIdentity>, with xlink:href
>     <reificationRef>? <reifiedRef>? <reifiesRef>? <subjectRef>?
>     favourite: <reificationRef>
>     bad: can't think of a good name
>     bad: means when you process the topic you don't know what
>          it reifies, so you have to remember until you find the thing
>The editors haven't really landed here, but are proceeding with 4) as
>a working hypothesis for the moment. However, suggestions further down
>imply that 1) might be made to work better.
I have a suggestion for reification in the model that might help with 
this issue in XTM 1.1.

What if topics were not required for reification?

I realize that is a serious departure from prior treatment of 
reification, but the model already specifies, even in the absence of a 
reifying topic, how to merge the various information items in the model.

Tokens in an information system always represent some subject. It is 
simply the nature of tokens in an information system that they have 
meaning to someone within a framework of tokens. But, standing alone, 
they do not reify subjects.

What is of the essence of reification is the occurrence of properties 
together that collectively enable an information item to represent a 
subject. That is to say a subject is "reified" when it is represented by 
properties that serve together to identify a subject.

Although as I  mentioned this is a serious departure from the current 
stance on reification, it would avoid the various options you list for 
changing XTM 1.1, none of which looks all that attractive.

I think the division of labor as it were, between topics, associations 
(relationships between topics), and occurrences (a specialized form of 
association) still obtains with my proposal without the overhead of 
having to track topics for reification connections.

There may be some serious flaw that I have not noticed in this proposal 
but after reading your comments on changes needed to XTM 1.1 I thought 
it would be worth suggesting.

Hope you are having a great day!


PS: After NOON tomorrow I am going to be on the road and may or may not 
have regular email access until I get back in office on Saturday.

Patrick Durusau
Chair, V1 - Text Processing: Office and Publishing Systems Interface
Co-Editor, ISO 13250, Topic Maps -- Reference Model
Member, Text Encoding Initiative Board of Directors, 2003-2005

Topic Maps: Human, not artificial, intelligence at work!