R501 - modelint/shlaer-mellor-metamodel GitHub Wiki

R501 / 1:1c

Assigner resolves competition on exactly one Association

Association competition is resolved by zero or one Assigner

---

Only those Associations where Instances on each side are competing to reference the other side require an Assigner. Typically, most Associations are non-competitive and can be easily managed with Class Methods or State Procedures on one or both sides.

On a given Association, there either is or isn’t an Assigner defined.