A Unifying Model Checking Approach for Safety Properties of Parameterized Systems

We present a model checking algorithm for safety properties that is applicable to parameterized systems and hence provides a unifying approach of model checking for parameterized systems. By analysing the conditions under which the proposed algorithm terminates, we obtain a characterisation of a subclass for which this problem is decidable. The known decidable subclasses, token rings and broadcast systems, fall in our subclass, while the main novel feature is that global guards (in form of unnested quantification over index variables) are allowed under certain circumstances. The approach is illustrated by the Bakery algorithm and the Illinois protocol.