2013/06/18 by Louis, Anand, Makarychev, Konstantin
#Data Structures and Algorithms (cs.DS) #FOS: Computer and information sciences
paper · doi:10.48550/arxiv.1306.4384
Given a graph G, the sparsest-cut problem asks to find the set of vertices S which has the least expansion defined as ϕG(S) := \fracw(E(S,S))min \setw(S), w(S), where w is the total edge weight of a subset. Here we study the natural generalization of this problem: given an integer k, compute a k-partition \setP1, …, Pk of the vertex set so as to minimize ϕk(\setP1, …, Pk) := maxi ϕG(Pi). Our main result is a polynomial time bi-criteria approximation algorithm which outputs a (1 - \e)k-partition of the vertex set such that each piece has expansion at most Oε(√(log n log k)) times OPT. We also study balanced versions of this problem.