The integrity of a cubic graph

  • Authors:
  • A. Vince

  • Affiliations:
  • Department of Mathematics, University of Florida, Gainesville, FL

  • Venue:
  • Discrete Applied Mathematics
  • Year:
  • 2004

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Abstract

Integrity, a measure of network reliability, is defined as I(G) = minS ⊂ E {|S| + m(G - S)}, where G is a graph with vertex set V and m(G-S) denotes the order of the largest component of G - S. We prove an upper bound of the following form on the integrity of any cubic graph with n vertices: I(G) n + O(√n) Moreover, there exist an infinite family of connected cubic graphs whose integrity satisfies a linear lower bound I(G) βn for some constant β. We provide a value for β, but it is likely not best possible. To prove the upper bound we first solve the following extremal problem. What is the least number of vertices in a cubic graph whose removal results in an acyclic graph? The solution (with a few minor exceptions) is that n/3 vertices suffice and this is best possible.