XMI21 — XMI for TypeLibrary::Objects::Object is Unspecified

Issue for XMI for MOF 2

The specification of XMI for MOF 2 does not describe handling of MOF's
object type, which is a supertype of ordinary class types as well as data
types. Particularly, it does not describe what XML results from the
following small example. The whole model is this:

In a package M there is one class X having one owned attribute named Y of
type TypeLibrary::Objects::Object with multiplicity 1..1.

Consider the following 4 instances of X:

1. An instance of X having Y set to the second instance of X.
2. An instance of X having Y set to the integer 3.
3. An instance of X having Y set to the string "this UNICODE string".
4. An instance of X having Y set to that same fourth instance of X.

What would an XMI-based serialization of these four instances of X look
like?

What would an XML schema for the package M look like?