The surviving rate of planar graphs

  • Authors:
  • Jiangxu Kong;Weifan Wang;Xuding Zhu

  • Affiliations:
  • -;-;-

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2012

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Abstract

Let G be a connected graph with n=2 vertices. Let k=1 be an integer. Suppose that a fire breaks out at a vertex v of G. A firefighter starts to protect vertices. At each time interval, the firefighter protects k-vertices not yet on fire. At the end of each time interval, the fire spreads to all the unprotected vertices that have a neighbor on fire. Let sn"k(v) denote the maximum number of vertices in G that the firefighter can save when a fire breaks out at vertex v. The k-surviving rate @r"k(G) of G is defined to be @?"v"@?"V"("G")sn"k(v)/n^2, which is the average proportion of saved vertices. In this paper, we show that every planar graph G with minimum degree @d satisfies @r"4(G)311 if @d=5, @r"4(G)319 if @d=4, and @r"4(G)19 if @d@?3. This improves a result in [W. Wang, S. Finbow, P. Wang, The surviving rate of an infected network, Theoret. Comput. Sci. 411 (2010) 3651-3660].