Given that the XMI spec contains a metamodel for XML Schema it would be possible to express the Schema production rules using QVT as a transformation from the MOF metamodel to the XSD metamodel. This would create a more rigorous specification that could be automated

The XMI is not explicit as to how to serialize values of the PrimitiveType UnlimitedNatural. In practice, and in the normative metamodels for UML as well as MOF, the value ‘’ has been used to represent ‘unlimited’ (as opposed to the value ‘-1’ which was used at UML/MOF 1.x). Rule 2i in section 6.3 states: Use this production rule to serialize an attribute whose type is not an object and whose value can be represented by a string. Multi-valued attributes cannot be serialized as XML attributes. If the attribute’s type is one of the types defined by the XML Schema Part 2: Datatypes specification, serialize the value as specified in that specification. PROPOSED RESOLUTION Add the following sentence to the end of the above paragraph: “Unless specified otherwise, values of other types may be serialized as strings using any permitted visual notation for that type. This applies to values for the Primitive Type UnlimitedNatural, where unlimited is serialized, as well as displayed, as ‘’.

There are two typo's for element 2h:FeatureAttrib. >From Document: ------------------- 2h:FeatureAttrib ::= X2i:MIValueAttribute | 2jXMIReferenceAttribute ------------------- - X is misplaced for 2i element - missing colon for 2j element Should be: ------------------- 2h:FeatureAttrib ::= 2i:XMIValueAttribute | 2j:XMIReferenceAttribute -------------------

There are two issues in this section of the document pertaining to referencing elements which only exist in the specification for the previous version, formal/05-05-01 (which is a changebar version of formal/03-05-02). First issue: 1:Document references 2:ContentElements. Here, 2:ContentElements does not exist in the formal/05-09-01 specification. Second issue: 1a:XMI references 5j:Extension. Here, 5j:Extension does not exist in the formal/05-09-01 specification.