R500 - modelint/shlaer-mellor-metamodel GitHub Wiki
R500 / 1:1c
Lifecycle specified pattern of behavior for exactly one Class
Class behavior pattern is specified by zero or one Lifecycle
By definition, a Lifecycle defines the common behavior on all instances a Class.
A Class, may exhibit such limited behavior (a single state, for example) that it does not warrant the specification of a Lifecycle. So while we can imagine a Lifecycle on every Class, in practice we build them only for Classes with interesting behavior.
Since a Class is defined as a set of things with the same behavior, it stands to reason that a Class can specify at most one Lifecycle.