Some readers have requested clarification about the assumptions on the capabilities of searchlights. In particular, about whether boundary searchlights can rotate past their adjacent walls. As stated in the literature, a searchlight is a rotatable beam sensor which ``cannot penetrate the environment boundary''. It is intended here that the environment boundary only restricts a searchlight's ability to sense, not its rotation. All searchlights, even those located on the environment boundary, are free to rotate 360 degrees. A beam may thus have length zero if its respective searchlight is aiming into a wall, but it is free to aim there. This assumption on searchlight rotation capabilities is the most natural because it means that there is no discontinuity in a searchlight's rotation range as its location approaches and then goes onto the environment boundary. There also are important computational implications of the assumption, e.g., to guarantee a rotation monotone schedule exists as in Conjecture 3.1 of the IJCGA paper A Complete Algorithm for Searchlight Scheduling.

Last modified: Sun Feb 5 23:07:46 MST 2012