UMLR — More detail on Express

What is a symbol? Suggest: a symbol such as "+" may be used to define the functionality of a particular expression node.

Are there any semantics for the inherited name? Suggest: the inherited name may be used to give distinct identifications to expression nodes.

Are there any semantics for the inherited type? Suggest: the inherited type may be used to identify the type resulting from evaluation of the expression node.

What type should be used for a set of values? Suggest: a domain-specific type system may be appropriate to represent a richer or more specific variety of values than can be modeled directly in UML.