An algorithm for computing the mask value of the supremal normal sublanguage of a legal language

We consider the problem of finding the mask value of the supremal normal sublanguage L/sub R/ of some given language L. We describe a straightforward algorithmic solution that can be applied to existing off-line procedures for determining the supremal controllable and normal sublanguage of L and that does not require an explicit calculation of L/sub R/. This problem is fundamental because it is related to the supervisory control problem under partial observation. Our algorithm applies only to closed languages.<
>