UMLR — Definition of invariant condition

This is not the normal interpretation of invariant conditions, and I believe it has no support in UML 2.4.1. The typical definition for invariant condition is that it must be true (it must hold) whenever it is checked, pre, post, and during. However, it need not hold while the object is not at a stable point and not query-able (not inspectable), but it must be true when and if the condition can be checked (by normal means). In an environment with multi-threading, this is often done with locks of some sort.