Theory of Computing ------------------- Title : The Minimum Bisection in the Planted Bisection Model Authors : Amin Coja-Oghlan, Oliver Cooley, Mihyun Kang, and Kathrin Skubch Volume : 13 Number : 8 Pages : 1-22 URL : https://theoryofcomputing.org/articles/v013a008 Abstract -------- In the planted bisection model a random graph $G(n,p_+,p_-)$ with $n$ vertices is created by partitioning the vertices randomly into two classes of equal size (up to $+/- 1$). Any two vertices that belong to the same class are linked by an edge with probability $p_+$ and any two that belong to different classes with probability $p_- < p_+$ independently. The planted bisection model has been used extensively to benchmark graph partitioning algorithms. If $p_{+/-}=2d_{+/-}/n$ for numbers $0\leq d_- < d_+$ that remain fixed as $n\to\infty$, then w.h.p. the "planted" bisection (the one used to construct the graph) will not be a minimum bisection. In this paper we derive an asymptotic formula for the minimum bisection width under the assumption that $d_+ -d_- > c\sqrt{d_+ \ln d_+}$ for a certain constant $c> 0$. A preliminary version of this paper appeared in the Proceedings of the 19th International Workshop on Randomization and Computation (RANDOM 2015).