We consider dynamic systems on time scales under the control of two agents.
One of the agents desires to keep the state of the system out of a given set
regardless of the other agent's actions. Leitmann's avoidance conditions are
proved to be valid for dynamic systems evolving on an arbitrary time scale.Comment: Revised edition in JOTA format. To appear in J. Optim. Theory Appl.
145 (2010), no. 3. In Pres