Maximally permissive mutually and globally nonblocking supervisors for discrete event systems

Abstract A supervisor is said to be mutually nonblocking with respect to a pair of specifications if upon completing a task in any of the specifications, it can continue on to complete the task in the other specification, i.e., the two specifications do not block each other. The notion of mutually nonblocking supervisor was introduced by Fabian and Kumar (2000). In this paper we present an algorithm of polynomial complexity for computing a maximally permissive mutually and globally nonblocking supervisor. The algorithm is based on a notion of attractability, and as a special case offers a new way of computing the maximally permissive nonblocking supervisors.