New optimality conditions for average-payoff continuous-time Markov games in Polish spaces

Abstract

This paper concerns two-person zero-sum games for a class of average-payoff continuous-time Markov processes in Polish spaces. The underlying processes are determined by transition rates that are allowed to be unbounded, and the payoff function may have neither upper nor lower bounds. We use two optimality inequalities to replace the so-called optimality equation in the previous literature. Under more general conditions, these optimality inequalities yield the existence of the value of the game and of a pair of optimal stationary strategies. Under some additional conditions we further establish the optimality equation itself. Finally, we use several examples to illustrate our results, and also to show the difference between the conditions in this paper and those in the literature. In particular, one of these examples shows that our approach is more general than all of the existing ones because it allows nonergodic Markov processes.