Abstract. We consider the problem of verifying whether one action theory can simulate a second one. Action theories provide modular descriptions of state machines, and simulation means that all possible sequences of actions in one transition system can be matched by the other. We show how Answer Set Programming can be used to automatically prove simulation by induction from an axiomatisation of two action theories and a projection function between them. Our interest in simulation of action theories comes from general game-playing robots as systems that can understand the rules of new games and learn to play them effectively in a physical environment. A crucial property of such games is their playathat is, each legal play sequence in the abstract game must be executable in the real environment.