KERML — isComposite, semantics

Composite features (Feature::isComposite=true) are described as

Values of a composite feature, on each instance of the feature's domain, cannot exist after the featuring instance ceases to exist. This only applies to values at the time the instance goes out of existence, not to other things in the co-domain that might have been values before that.

but this semantics is not math/modeled and Core does not include models of time.