Runtime veri?cation is a recent direction in formal methods research, which is complementary to such well-established formal veri?cation methods as model checking. Research in runtime veri?cation deals with formal languages suitable for expressing system properties that are checkable at run time; algorithms for checking of formal properties over an execution trace; low-overhead means of extracting information from the running system that is su?cient for checking of the property. Applications of runtime veri?cation technology include po- deployment monitoring of system correctness and...