If no ModellingRuleexists then the Nodeis neither considered for instantiation of a type nor for subtyping.

If a Nodereferenced by a TypeDefinitionNodedoes not reference a ModellingRuleit indicates that this Nodeonly belongs to the TypeDefinitionNodeand not to the instances. For example, an ObjectType Nodemay contain a Propertythat describes scenarios where the type could be used. This Propertywould not be considered when creating instances of the type. This is also true for subtyping, that is, subtypes of the type definition would not inherit the referenced Node.