There are two mechanisms for terminating execution.
First, a mechanism exists to determine whether there is work yet to be performed anywhere in the environment. When tile states are created, the user is able to declare them as either terminal or non-terminal. On each execution cycle, the system examines the state of each tile in the map, and determines whether any of them are non-terminal. If there are no non-terminal states, execution completes. The compulsory problem solution, later in this paper, makes use of this mechanism.
Second, a mechanism exists for determining that a goal has been
accomplished. Termination states exist for both tile and robot
states. If either a tile or the robot is put in the termination
state, execution stops immediately. The final problem solution
makes use of this mechanism.