Abstract
We study the problem of maintainability of the structure in a non‐homogeneous Markov ystem (NHMS) by input control. The set of maintainable structures is given as the convex hull of n‐points in Rn where n is the number of states of the NHMS. We also study the problem of attainability in a NHMS by input control and an algorithm is provided for the optimal policy in this respect. Finally, we provide applications of the present results to a large British firm