DMN11 — dmn3.xsd

This issue separates the dmn3.xsd issues from DMN11-9, which otherwise concerns dmn.xsd.
There are a number of serious problems with dmn3.xsd:
1. Syntactically incorrect. The include of dmn.xsd points to the wrong filename. The only reason why include is needed (syntactically) is to reference tExpression.
2. tExpression is not the right datatype for the elements. See DMN11-9 for why.
3. dmn3.xsd does not represent what 12.2.2 says it does. It is not an interchange format for Level 3 decision models! It is just a schema for a context. And it is not even the right schema for a context. Serialization of a context does not use elements named ContextEntry, List, Relation, etc. You can see that from 10.3.3.3.1 and 10.3.3.3.2. I think it is meant to clarify the semantics of context, but it would never be used in serialization.

For these reasons I propose that 12.2 is modified and dmn3.xsd is removed from the specification. If a separate schema is needed to serialize Level 3, it must contain the whole thing, starting from Definitions. I don't think a separate schema is needed, but we should check if the existing element for output variable, InformationItem, can describe a context.

close and merge with dmn11-91

The issues with dmn3.xsd are addressed by dmn11-61, dmn11-94 and others.