Abstract
We propose a new variation of the art gallery problem. We first define the guards visibility graph in which all vertices represent guards and there is an edge between two guards if and only if these two guards can see each other. Our minimum cooperative guards problem requires that the resulting guards visibility graph of the solution must be connected and of course the number of guards is minimized. We show that this problem is NP-hard for general polygons. We also propose two linear algorithms for solving this problem on k-spiral polygons, for k=1 and 2