What Topology tells us about Diagnosability in partial order semantics

From a partial observation of the behaviour of a labeled Discrete Event System, fault Diagnosis strives to determine whether or not a given “invisible” fault event has occurred. The diagnosability problem can be stated as follows: does the labeling allow for an outside observer to determine the occurrence of the fault, no later than a bounded number of events after that unobservable occurrence ? In concurrent systems, partial order semantics...