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On the connectedness of a random graph

Published online by Cambridge University Press:  24 October 2008

G. R. Grimmett
Affiliation:
School of Mathematics, University of Bristol, England
M. Keane
Affiliation:
Department of Mathematics and Informatics, Delft University of Technology, The, Netherlands
J. M. Marstrand
Affiliation:
School of Mathematics, University of Bristol, England

Abstract

Let p = (p(i): i ≥ 0) be a sequence of numbers satisfying 0 ≤ p(i) < 1 for i = 0,1,2,…, and let G be a random graph with vertex set ℤ = {…, — 1, 0, 1,…} and with edge set defined as follows: for each pair i, j of vertices, where ij, there is an edge joining i and j with probability p(ji), independently of the presence or absence of all other edges. We explore the connectedness of G, showing that G is almost surely connected if and only if Σip(i) = ∞ and the (positive) greatest common divisor of the set {i ≥ 1: p(i) < 0} equals 1; if one of these two conditions fails to hold then G is almost surely disconnected. Corresponding results hold in higher dimensions, for random graphs defined on the vertex sets ℤd where d ≥ 2.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1984

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References

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