Cooperative guards in art galleries
The art gallery problem was originally posed by Victor Klee in 1973 as the question of determining the minimum number of guards sufficient to see every point of the interior of an n-vertex simple polygon. The guard is assumed to be a stationary point which can see any other point that can be connected to it by a line segment within the art gallery. The first result is due to Chvátal (1975), who proved that ⌊n/3⌋ guards are occasionally necessary and always sufficient to cover a polygon with n vertices....