English

On percolation and the bunkbed conjecture

Combinatorics 2009-11-30 v2 Probability

Abstract

We study a problem on edge percolation on product graphs G×K2G\times K_2. Here GG is any finite graph and K2K_2 consists of two vertices {0,1}\{0,1\} connected by an edge. Every edge in G×K2G\times K_2 is present with probability pp independent of other edges. The Bunkbed conjecture states that for all GG and pp the probability that (u,0)(u,0) is in the same component as (v,0)(v,0) is greater than or equal to the probability that (u,0)(u,0) is in the same component as (v,1)(v,1) for every pair of vertices u,vGu,v\in G. We generalize this conjecture and formulate and prove similar statements for randomly directed graphs. The methods lead to a proof of the original conjecture for special classes of graphs GG, in particular outerplanar graphs.

Keywords

Cite

@article{arxiv.0811.0949,
  title  = {On percolation and the bunkbed conjecture},
  author = {Svante Linusson},
  journal= {arXiv preprint arXiv:0811.0949},
  year   = {2009}
}

Comments

13 pages, improved exposition thanks to anonymous referee. To appear in CPC

R2 v1 2026-06-21T11:38:52.120Z