UML22 — UML 2 Issue: definition of navigability

PROBLEM STATEMENT
There is no definition for navigability or navigation in the Spec. Other
concepts of similar importance, such as visibility, multiplicity, etc., are
defined in the Spec, so it is not clear why it should be assumed that this
concept does not require a definition.

PROPOSED SOLUTION
Add definition in Section 4 (Terms and definitions): The navigability of a
binary association specifies the ability of an instance of the source
classifier to access the instances of the target classifier by means of the
association instances (links) that connect them. Navigability is closely
related to the possibility of sending messages through associations (a
message cannot be sent through an association instance against its
navigability, that is, navigability is required for sending messages through
associations), but they remain nonetheless different concepts.

Discussion: This issue was resolved in UML 2.1 where an explanation of navigability was provided (see page 41 top in formal/07-02/05) Revised Text: N/A Disposition: Closed, no change