[sc34wg3] New SAM PSIs

[Mary Nishikawa]

[Dmitry ]
>I think that there are two different models which are discussed in this
>thread.
>
>More precisely, I think that:
>
>It is possible to create different models explaining "class-subclass","
>instance-class" relationships.
>
>It is possible to create useful model (let's call it M0) of "class-subclass"
>," instance-class" relationships that is not based on concept of extensions.
>This model does not have superclass-subclass loops by definition.
>
>Class-subclass model used in SAM (M1) is out of scope of M0, it is a
>different model with different "axioms". I guess one of the first "axioms"
>of M1 is that "A type is a set of individual subjects, each of which is an
>instance of the type."

Now I will go back and read SAM again.
I did not realize that the M0 model is out of scope of SAM.
Is this an XTM syntax versus SAM issue perhaps. I am really not sure and 
would like to confirm this.
(What I mean is, you can create a M0 model in XTM syntax, but this is not 
what is  in SAM?

>*Dmitry
>M0 and M1 use the same terms "class", "subclass", "type", "subtype" but
>because of different "axioms" these terms have different meaning.  It is
>"difficult" to discuss M1 and M0 as one model.
>
>Question that I have: Do we want to discuss M0 if we know that SAM is based
>on M1?

I guess I would like to know if this is the case, then I will go back and
review and compare SAM and the XTM syntax specs, from this perspective.

Cheers,
Mary