Citation

Js. Naor et L. Zosin, A 2-approximation algorithm for the directed multiway cut problem, SIAM J COMP, 31(2), 2001, pp. 477-482

Citations number

7

Language

INGLESE

art.tipo

Article

Categorie Soggetti

Computer Science & Engineering

Journal title

SIAM JOURNAL ON COMPUTING

ISSN journal

0097-5397
â†’ ACNP

Volume

31

Issue

2

Year of publication

2001

Pages

477 - 482

Database

ISI

SICI code

0097-5397(20011011)31:2<477:A2AFTD>2.0.ZU;2-C

Abstract

A directed multiway cut separates a set of terminals T = {s(1),...,s(k)} in
a directed capacitated graph G=(V,E). Finding a minimum directed multiway
cut is an NP-hard problem. We give a polynomial-time algorithm that achieve
s an approximation factor of 2 for this problem. This improves the result o
f Garg, Vazirani, and Yannakakis [ Proceedings of the 21st International Co
lloquium on Automata, Languages, and Programming, Jerusalem, Israel, 1994,
pp. 487-498], who gave an algorithm that achieves an approximation factor o
f 2 log k. Our approximation algorithm uses a novel technique for relaxing
a multiway ow function in order to nd a directed multiway cut. It also impl
ies that the integrality gap of the linear program for the directed multiwa
y cut problem is at most 2.