R157 - modelint/shlaer-mellor-metamodel GitHub Wiki
R157 / 1:1
Simple Association Reference is housed in exactly one Referring Class
Referring Class houses exactly one Simple Association Reference
An Association that is not formalized by an Association Class is formalized by one of its participating Classes in the direction of a one-unconditional Perspective.
By 'housed' in a Class, we mean that the Reference's referential attributes are all defined in that Class.
Formalization
Simple Association Reference.(From class, Rnum, Domain) -> Referring Class.(Class, Rnum, Domain)