Lee Riemenscheider's comments

[Leon Starr]

Hi Leon,

I'm going suggest some more changes to the metamodels. I would send
them as BridgePoint models, but I don't presently have a copy
installed at home. Hopefully, Cortland Starrett will be sending me a
beta copy of the Linux version soon. I don't know if I can still
import version 5.1 models anyway.

I think these changes will allow the metamodels to properly support
generalization instances. i.e., a superclass and subclass make one
instance. At least that's what led to these changes.

Class and Attribute Subsystem:
1. Remove R21.
2. Add the <<imported>> class, Instance.
3. Relate Instance to Identifier as:
"An Instance has uniqueness determined by one or more Identifiers."
"An Identifier determines uniqueness of one Instance."
NOTES: Classes don't really have a need for identifiers. Instances
always require an identifier, either implicit or explicit.

Population Subsystem:
1. Remove the Population class.
2. Remove R403.
3. Relate Instance to Class with association class, Class Population
as:
"A Class is populated by zero to many Instances as a Class
Population."
"An Instance populates one or more Classes via a Class Population."
NOTES: In the absence of descriptions for this subsystem, I had some
trouble trying to determine exactly what was the class, Population. I
settled on it's meaning as, "population of instances", which led to me
thinking that it was redundant with the classes, Class Population and
Instance.

Domain Subsystem:
1. Replace Population with Instance and R8 now reads:
"A Domain gets data from zero to many Instances."
"An Instance supplies data to only one Domain."

Let me know what you think of these changes.

Thank you,
Lee Riemenschneider