Title
How Many Lions Are Needed To Clear A Grid?
Abstract
We consider a pursuit-evasion problem where some lions have the task to clear a grid graph whose nodes are initially contaminated. The contamination spreads one step per time unit in each direction not blocked by a lion. A vertex is cleared from its contamination whenever a lion moves to it. Brass et al. [5] showed that i lions are not enough to clear the n x n-grid. In this paper, we consider the same problem in dimension d > 2 and prove that Theta(n(d-1)/root d) lions are necessary and sufficient to clear the n(d)-grid. Furthermore, we analyze a problem variant where the lions are also allowed to jump from grid vertices to non-adjacent grid vertices.
Year
DOI
Venue
2009
10.3390/a2031069
ALGORITHMS
Keywords
Field
DocType
lion and man, safe path planning, avoidance number, pursuit games, graph separator, graph search, isoperimetric inequality
Mathematical optimization,Combinatorics,Vertex (geometry),Clearance,Lattice graph,Isoperimetric inequality,Mathematics,Grid
Journal
Volume
Issue
ISSN
2
3
1999-4893
Citations 
PageRank 
References 
4
1.16
6
Authors
4
Name
Order
Citations
PageRank
Florian Berger1237.05
Alexander Gilbers241.50
Ansgar Grüne3828.73
Rolf Klein4465.08