Lecture Notes in Computer Science 1755 EditedbyG.Goos, J. Hartmanis and J. vanLeeuwen Dines Bjørner Manfred Broy Alexandre V. Zamulin (Eds.) Perspectives of System Informatics Third International Andrei Ershov Memorial Conference, PSI’99 Akademgorodok, Novosibirsk, Russia July 6-9, 1999 Proceedings 1 3 SeriesEditors GerhardGoos,KarlsruheUniversity,Germany JurisHartmanis,CornellUniversity,NY,USA JanvanLeeuwen,UtrechtUniversity,TheNetherlands VolumeEditors DinesBjørner TechnicalUniversityofDenmark,DepartmentofInformationTechnology Bldg.244,2800Lyngby,Denmark E-mail:[email protected] ManfredBroy TechnicalUniversityofMunich,ComputerScienceDepartment Arcisstr.21,80290Munich,Germany E-mail:[email protected] AlexandreV.Zamulin A.P.ErshovInstituteofInformaticsSystems av.Ac.Lavrentyev6,Novosibirsk630090,Russia E-mail:[email protected] Cataloging-in-Publicationdataappliedfor DieDeutscheBibliothek-CIP-Einheitsaufnahme Perspectivesofsysteminformatics:proceedings/ThirdInternational AndreiErshovMemorialConference,PSI’99,Akademgorodok, Novosibirsk,Russia,July6-9,1999.DinesBjørner...(ed.).- Berlin;Heidelberg;NewYork;Barcelona;HongKong;London; Milan;Paris;Singapore;Tokyo:Springer,2000 (Lecturenotesincomputerscience;Vol.1755) ISBN3-540-67102-1 CRSubjectClassication(1998):F.3,D.3,D.1,D.2,I.2 ISSN0302-9743 ISBN3-540-67102-1Springer-VerlagBerlinHeidelbergNewYork Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthematerialis concerned,specicallytherightsoftranslation,reprinting,re-useofillustrations,recitation,broadcasting, reproductiononmicrolmsorinanyotherway,andstorageindatabanks.Duplicationofthispublication orpartsthereofispermittedonlyundertheprovisionsoftheGermanCopyrightLawofSeptember9,1965, initscurrentversion,andpermissionforusemustalwaysbeobtainedfromSpringer-Verlag.Violationsare liableforprosecutionundertheGermanCopyrightLaw. ©Springer-VerlagBerlinHeidelberg2000 PrintedinGermany Typesetting:Camera-readybyauthor SPIN:10719596 06/3142–543210 Printedonacid-freepaper                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       