Using Abstraction in Model Checking Z Specifications

The Z notation is a language used for writing formal specifications of a system. However, tool support for this language is lacking. One such tool that is not generally available is a model checker. Model checking is a method used to verify that a system has certain properties, this is important since it can provide full verification of a finite state system without the user having sophisticated knowledge. Originally applied in hardware systems, it is now commonly available for application in software systems. One of the drawbacks of model checking is that it applies to finite state systems, since it works by performing a complete state space exploration. However, the size of the systems that model checkers can now cope with has increased rapidly. In this paper, the use of abstraction as a means to make model checking feasible for arbitrary Z specifications is investigated. Several experiments have shown that the abstract models have fewer states than the concrete ones or have the same number of states as the concrete one.