Max Cut and the Smallest Eigenvalue

dc.creatorTrevisan, Luca
dc.date2008-06-12
dc.date2008-12-08
dc.date.accessioned2026-07-07T12:09:40Z
dc.date.available2026-07-07T12:09:40Z
dc.descriptionWe describe a new approximation algorithm for Max Cut. Our algorithm runs in $\tilde O(n^2)$ time, where $n$ is the number of vertices, and achieves an approximation ratio of $.531$. On instances in which an optimal solution cuts a $1-ε$ fraction of edges, our algorithm finds a solution that cuts a $1-4\sqrtε + 8ε-o(1)$ fraction of edges. Our main result is a variant of spectral partitioning, which can be implemented in nearly linear time. Given a graph in which the Max Cut optimum is a $1-ε$ fraction of edges, our spectral partitioning algorithm finds a set $S$ of vertices and a bipartition $L,R=S-L$ of $S$ such that at least a $1-O(\sqrt ε)$ fraction of the edges incident on $S$ have one endpoint in $L$ and one endpoint in $R$. (This can be seen as an analog of Cheeger's inequality for the smallest eigenvalue of the adjacency matrix of a graph.) Iterating this procedure yields the approximation results stated above. A different, more complicated, variant of spectral partitioning leads to an $\tilde O(n^3)$ time algorithm that cuts $1/2 + e^{-Ω(1/\eps)}$ fraction of edges in graphs in which the optimum is $1/2 + ε$.
dc.identifierhttps://arxiv.org/abs/0806.1978
dc.identifierhttp://arxiv.org/abs/0806.1978
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/209701
dc.subjectData Structures and Algorithms
dc.titleMax Cut and the Smallest Eigenvalue
dc.typetext

Files

Collections