Preface Volume 20

AbstractThis volume contains the Proceedings of the Fifteenth Conference on the Mathematical Foundations of Programming Semantics. The Conference was held on the campus of Tulane University, New Orleans, LA from April 28 to May 1, 1999. The meeting was co-chaired by Stephen Brookes and Michael Mislove.The papers in this volume were selected by the Program Committee from submissions received in response to a Call for Papers, or were solicited by the Organizers and the Program Committee. As has been customary with past MFPS Conferences, these final Proceedings are being published after the meeting has concluded to allow the authors to have a chance to revise their papers. Thanks are due to a number of people who have helped organize and plan the conference. Among this group are the Program Committee chaired by Achim Jung (Birmingham) and Andre Scedrov (Pennsylvania), and whose members include the following: Stephen Brookes CMUPeter O'Hearn Queen Mary and WestfieldAdriana Compagnoni Stevens InstituteCatuscia Palamidessi Penn StateKathleen Fisher AT&TPrakash Panangaden McGillPaul Gastin LIAFADusko Pavlovic KestrelAndrew Gordon Microsoft ResearchAndrew Pitts CambridgeReinhold Heckmann SaarbrückenA. W. Roscoe OxfordCatherine Meadows NRLGiuseppe Rosolini GenoaMichael Mislove TulaneJan Rutten CWIEugene Stark Stony BrookAlso, thanks are due to the anonymous referees who helped review the submissions for the meeting.The invited speakers at the meeting were: Martin Abadi(Compaq Systems Research Center)Matthew Hennessy(University of Sussex)Tom Henzinger(University of California at Berkeley)Max Kanovich(Russian Humanities State University)Uday Reddy(University of Illinois)Peter Selinger(University of Michigan)There were two special sessions during the meeting. The first was organized by Uday Reddy (Illinois) and Peter O'Hearn (Queen Mary and Westfield College) on Object-Oriented Prorgamming. It began with an invited address by Professor Reddy, and included talks by Paulo Sergio Almeida (Universidade do Minho), Vivana Bono (Torino), Kim Bruce (Williams College), and Peter O'Hearn. The papers from this session are grouped together in this Proceedings volume.The second special session focused on Security Protocols. It was organized by Catherine Meadows (NRL) and Dennis Volpano (Naval Postgraduate School). It began with an invited address by Martin Abadi (Compaq Systems Research Center), and an introductory talk by Catherine Meadows, followed by by Paul Syverson (NRL), Geoff Smith (Florida International University), Dominique Bolignano (Trusted Logic), Carl Gunter (Pennsylvania), Pat Lincoln (SRI International) and George Necula (UC Berkeley). Cathy and Dennis have kindly prepared a short introduction to security protocols for this proceedings, which is followed by the group of papers from this session.The Organizers for the MFPS series are Stephen Brookes (CMU), Michael Main (Colorado), Austin Melton (Kent State), Michael Mislove (Tulane) and David Schmidt (Kansas State). On behalf of the participants, we wish to express our thanks both to the Office of Naval Research, and especially to Dr. Ralph Wachter, who have generously supported this series.Lastly, we also wish to thank Ms. Geralyn Caradona, who provided her usual efficient attention to discharging the many details of arranging for the meeting needs. Without her efforts, the meeting would not have run as {smoothly} nor have been as productive and enjoyable as it was for the participants