Title
On guarding the vertices of rectilinear domains
Abstract
We prove that guarding the vertices of a rectilinear polygon P, whether by guards lying at vertices of P, or by guards lying on the boundary of P, or by guards lying anywhere in P, is NP-hard. For the first two proofs (i.e., vertex guards and boundary guards), we construct a reduction from minimum piercing of 2-intervals. The third proof is somewhat simpler; it is obtained by adapting a known reduction from minimum line cover. We also consider the problem of guarding the vertices of a 1.5D rectilinear terrain. We establish an interesting connection between this problem and the problem of computing a minimum clique cover in chordal graphs. This connection yields a 2-approximation algorithm for the guarding problem.
Year
DOI
Venue
2008
10.1016/j.comgeo.2007.02.002
Comput. Geom.
Keywords
DocType
Volume
connection yield,geometric optimization,minimum clique cover,boundary guard,rectilinear polygon,approximation algorithms,rectilinear terrain,np-hardness,minimum line,rectilinear domain,2-approximation algorithm,known reduction,guarding,interesting connection,minimum piercing,chordal graph
Journal
39
Issue
ISSN
Citations 
3
Computational Geometry: Theory and Applications
23
PageRank 
References 
Authors
1.22
16
2
Name
Order
Citations
PageRank
Matthew J. Katz122519.92
Gabriel S. Roisman2241.60