Copyright © 2004 by the Association for Computing Machinery, Inc. and the Society for industrial and Applied Mathematics. All Rights reserved. Printed in The United States of America. No part of this book may be reproduced, stored, or transmitted in any manner without the written permission of the publisher. For information, write to the Association for Computing Machinery, 1515 Broadway, New York, NY 10036 and the Society for Industrial and Applied Mathematics, 3600 University City Science Center, Philadelphia, PA 19104-2688

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262


G2 G1 G4 u G6 G7 D G
5

G3

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Some old clusters

u D

Before

Tlocal

After The shaded area forms the new cluster U'

264


265


266


267


268


r

r'

edges of T edges of T' bridge edges

269


270