We study deterministic discounted optimal control problems associated with
discrete-time systems. It is shown that, for small discount rates, the cont
rollability properties of the underlying system can guarantee the convergen
ce of the discounted value function to the value function of the average yi
eld. An application in the theory of exponential growth rates of discrete i
nclusions is presented. This application motivates the analysis of infinite
-horizon optimal control problems with running yields that are unbounded fr
om below.