Decomposition of multiple coverings into many parts

  • Authors:
  • Janos Pach;Geza Toth

  • Affiliations:
  • Hungarian Academy of Sciences, Budapest, Hungary;Hungarian Academy of Sciences, Budapest, Hungary

  • Venue:
  • SCG '07 Proceedings of the twenty-third annual symposium on Computational geometry
  • Year:
  • 2007

Quantified Score

Hi-index 0.00

Visualization

Abstract

Suppose that the whole plane (or a large region) is monitored by aset S of stationary sensors such that each element s ∈ S canobserve an axis-parallel unit square R(s) centered at s, whichis called the range of s. Each sensor s is equipped witha battery of unit lifetime. Is it true that if every point of theplane belongs to the range of many sensors, then we can monitorthe plane for a long time without running out of power? If S canbe partitioned into k parts S1, S2,..., Sk such that, foreach i, the sensors in Si together can observe the wholeplane, then the plane can be monitored with no interruption fork units of time. Indeed, we can first switch on all sensorsbelonging to S1. After these sensors run out of battery, we canswitch on all elements of S2, etc.We arrive at the following problem. Let m(k) denote the smallestpositive integer m such that any m-fold covering of the planewith axis-parallel unit squares splits into at least kcoverings. We show that m(k)=O(k2), and generalize this resultto translates of any centrally symmetric convex polygon in theplace of squares. From the other direction, we know only that m(k) ≥ ⌊4k/3⌋ -1.