2021/11/05 by Zhiyang He, Jason Li, He, Zhiyang +1 · 1 citation
Computer Science · Mathematics · #05C85 #Combinatorics (math.CO) #Data Structures and Algorithms (cs.DS) #FOS: Computer and information sciences #FOS: Mathematics #cs.DS #math.CO #msc:05C85
paper · pdf · doi:10.48550/arxiv.2111.03221
arxiv created 2021/12/01 · arxiv updated 2021/12/02
In the minimum k-cut problem, we want to find the minimum number of edges whose deletion breaks the input graph into at least k connected components. The classic algorithm of Karger and Stein runs in O(n2k-2) time, and recent, exciting developments have improved the running time to O(nk). For general, weighted graphs, this is tight assuming popular hardness conjectures. In this work, we show that perhaps surprisingly, O(nk) is not the right answer for simple, unweighted graphs. We design an algorithm that runs in time O(n(1-ε)k) where ε>0 is an absolute constant, breaking the natural nk barrier. This establishes a separation of the two problems in the unweighted and weighted cases.