EXPRESS11 — Many 'subsets' properties should be 'redefines'

The metamodel defines a number of high-level common properties that are (or should be) constrained to subclass-subclass relationships in practice. Unfortunately many of these relationships are described as ‘subsets’ of the properties, while the EXPRESS specification is clear that they are constraints and therefore should be redefinitions. (Alternatively, some the high-level relationships could just be derived unions.)

The RTF agrees that almost all of the ‘subsets’ relationships to namespace or ‘of-type’ should be ‘redefines’. Similarly, the redefinitions of Expression.evaluation should be properly modeled by ‘redefines’.
The namespace relationships are repaired in the resolution to Issue 19031. The remaining ones – Instance ‘of-type’ and typed Expressions – are corrected here. The relationship between the IndeterminateRef expression and the Indeterminate Instance class is added.
These changes have no real affect on implementations, but they improve automatically generated code.