a NamedElement (EXPRESS model element) that can be defined in either a Schema or a LocalScope, and has (or may have) a unique identifier within that Scope. This is an artifact of the declaration and namespace rules for the EXPRESS language. NamedTypes, Algorithms, Constants, and "SupertypeRules" can be defined at the Schema level or within Algorithms and GlobalRules. The CommonElements whose Scope is a Schema are SchemaElements; the others are LocalElements.

represents the relationship between a CommonElement and the "scope" in which it is defined; also, the scope (set of model elements) in which the id of the CommonElement refers to that CommonElement.