The verification algorithm of SPIN is based on an explicit enumeration of a subset of the reachable state-space of a system that is obtained through the formalization of a correctness requirement as an -automaton. This -automaton restricts the state-space to precisely the subset that may contain the counter-examples to the original correctness requirement, if they exist. This method of verification conforms to the method for automata-theoretic verification outlined in [VW86]. SPIN derives

We consider the problem of storing a set S ae \Sigma as a deterministic finite automaton (DFA). Weshow that inserting a new string oe 2 \Sigma or deleting a string from the set S represented as a minimized DFA can be done in expected time O(kj\Sigmaj), while preserving the minimality of the DFA. We then discuss an application of this work to reduce the memory requirements of a model checker based on explicit state enumeration.

There is a need for formal methods to verify correctness of software and hardware systems. Automated verification techniques basically explore the state space of a system in order to establish whether or not it behaves correctly. The main drawback of such methods is the state explosion problem. The size of the state space can grow exponentially in the number of components of the system, especially in asynchronous concurrent systems. In early stages of system development, errors are likely to appear. As a matter of fact, in practice, automated verification has been shown to be more successful in finding errors in systems than in proving correctness. Usually, one applies reachability algorithms like depth-first, and breadth-first search for this purpose. Breadth-first search is, in general, not memory-efficient, but offers shortest counterexamples. On the other hand, depth-first search is more memory-efficient, but delivers suboptimal counterexamples. We propose and analyze the use of...

The verification algorithm of SPIN is based on an explicit enumeration of a subset of the reachable state-space of a system that is obtained through the formalization of a correctness requirement as an -automaton. This -automaton restricts the state-space to precisely the subset that may contain the counter-examples to the original correctness requirement, if they exist. This method of verification conforms to the method for automata-theoretic verification outlined in [VW86].