RE: [gmt-dev] evolving GMT in a fully open process that allows ot hers t

["Willink, Ed" <Ed.Willink@xxxxxxxxxxxxxxx>]

Hi

> Terminology-wise, to prevent meta modellers (users 
> who develop a
> meta model) from unadvertently slipping into the solution space, the
> following elements are required for meta modeling:
> 
> (a) CONCEPT - to represent the items being modelled
> (b) RELATIONSHIP - to represent binary relationships between concepts
> (c) ROLE - to represent the "Role" of one Concept in relation 
> to another
> Concept via a Relationship. Each Relationship needs to 
> provide a Role for
> the Concept at the "source" end of the Relationship and a Role for the
> Concept at the "target" end of the Relationship.
> (d) CONTAINER - a grouping mechanism for Concepts and 
> Relationships (which
> contain Role definitions)
> (e) PROPERTY - All the elements (a) ... (d) may contain any number of
> "atomic" Properties

I don't think this has been thought through.

If these terms are similar to conventional terms, then users will be well
confused.

If these terms are very different then users will be well confused unless
a major re-exposition of the prevailing state of the art is undertaken.

Modelling exists at multiple levels M0, M1, M2, M3. Introducing a new
set of names because the M1/M2 names can confuse will require yet
more names at M2/M3 or wherever.

For instance at the next level of abstraction all the above are CONCEPTS,
and at the same level of abstraction, a PROPERTY, CONTAINER and CONCEPT
are all varieties of 'thing'. Perhaps PROPERTY should be an ATOMIC CONCEPT,
derivation, and CONTAINER a COMPOUND CONCEPT derivation. Migration from
atomic to non-atomic is a regular occurence as a model elaborates. This
should not involve a major change of term. I'm not at all happy
about the equivalence of COMPOUND CONCEPT and COMPOUND RELATIONSHIP.

GMT is coming along too late, and with insufficient momentum, to redefine
the established terminology.

GMT must make the best of current practice.

If more precise concepts are needed then a term such as GmtClass or
GmtRelationship should be used wherever the more precise meaning matters.

	Regards
			
		Ed Willink

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