[sc34wg3] Association items

Patrick Durusau sc34wg3@isotopicmaps.org
Wed, 08 Jun 2005 20:00:13 -0400

This one was sent yesterday and was the first time I noticed that my 
posts weren't making it to the list. :-(


This is mainly directed at Lars and Graham but I thought others might be 
interested in the question and any ensuing discussion.

I am trying to model the various parts of the TMDM as assertions and in 
the course of re-reading the TMDM, I ran across the following at 5.7 
Association Items:

"An association is a representation of a relationship between one or 
more subjects."

I mined the SC34WG3 archives for prior discussion of this point and 
found Lars' post of April 18, 2003, subject line: Re: [sc34wg3] 
Questions on N0396 (2) one or more association memberships, pointing out:

This is a carry-over from HyTM and XTM., both of which allow unary
associations. The rationale, I have been told, was that unary
associations are essentially assertions about a single subject, such

is-inquisitive(jan : person)

SAM has ot have this because HyTM and XTM have it.

(For those of you with a historical interest, see Note 41 in ISO 
13250:1999 for HyTM and 2.2.4 Association for XTM. BTW, for newcomers to 
the community, "SAM" was the prior name for what has become the TMDM.)

There is no question Lars is correct about HyTM and XTM, but I am less 
certain that answers the question about how to model a "unary" association.

Note 41 (from ISO 13250) says: "Thus, the containing assoc element can 
assert that a topic has one or more specific relationships to itself."

Although it is represented in syntax as a "unary" association, shouldn't 
it be modeled as an association with two roles, etc.?

This is not the only place where the issue comes up, as topic name, for 
example, is mentioned as a specialized kind of occurrence (TMDM, page 
11) and it is later noted that an occurrence is a specialized form of an 
association (TMDM, page 13).

NOTE: I am NOT suggesting any change in syntax, processing, etc., but am 
asking if the "unary" association in syntax should be modeled as though 
it were an association with two (or more) roles, role players, etc. Some 
parts of which are implied, for example with topic name if it is 
considered ultimately to be a form of an association (I take it the 
roles are implied even though the role players are known).

Hope everyone is having a great day!


PS: For those of you who are interested, the example that Lars' gives 

is-inquisitive(jan : person)

Can be  seen  as  two roles: characteristic/person, with two role 
players: is-inquisitive/jan.

Suppose in the best tradition of English anyway, the role of 
characteristic is silent. ;-)

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!