Sami Lifsches
University of Groningen
Department of Mathematics and Computing Science
We will discuss the connections between Hybrid Systems, Tree Automata and
Monadic second-order Logic. Our main result is that a Hybrid System is
controllable by a tree automaton if and only if it is definable in the
monadic theory of the binary tree. A system that is not controllable may
become one if "looking ahead" is allowed. In that case, the system can be
approximated by a definable, controllable system.