We consider control questions for finite automata viewed as input/output systems. In particular, we find estimates of the minimal number of states of an automaton able to control a given automaton. We prove that, on average, feedback closed-loop control automata do not have fewer states than open-loop control automata when the control objective is to steer the controlled automaton to a target state. We compare our approach to other ways of formalizing of formalizing analogous control objectives.
Delvenne, J.-C., & Blondel, V. (2006). Complexity of control on finite automata. IEEE Transactions on Automatic Control, 51(6), 977-986. https://doi.org/10.1109/TAC.2006.876948 (Original work published 2006)