The Mathematical Institute Newsletter is maintained by Jan-Hendrik Evertse. The newsletter is issued the first week of each month, except for July and August. The electronic version of the newsletter can be found on http://www.math.leidenuniv.nl/~evertse/newsletter.shtml
(go to the homepage of the Mathematical Institute and click on "Newsletter").

Copy for the March 2005 newsletter, such as announcements, personal notes, visits to conferences, guests (with place of origin and date of arrival and departure), lectures of general interest, Ph.D. thesis defenses (with title of thesis), etc. should be sent by e-mail to evertse at math.leidenuniv.nl before February 27. Copy should be submitted in English plaintext, so that it can be inserted into the newsletter without time consuming typing or translating work.

Agenda and announcements

• Appointments for Ronald Cramer
   
  Ronald Cramer has been elected to the Board of Directors of the International Association of Cryptologic Research (IACR) for the 2005-2007 term, see http://www.iacr.org.
   
  Ronald Cramer has been chosen as a member of "De Jonge Akademie" ("The Young Academy"). This is a program, recently established by the KNAW (Royal Netherlands Academy of Arts and Sciences) meant for excellent young researchers, working at Dutch universities or institutes, who received their Ph.D. less than ten years ago, and who have distinguished themselves by receiving important grants or honours. The KNAW has chosen altogether 40 scientists (23 men and 17 women) by means of a public selection procedure to become a member of DJA. In 2006 the number of DJA-members will be increased to 50. A DJA-membership lasts at most five years. The purpose of the DJA-program is to foster interaction between young researchers from various disciplines working on Dutch universities or institutes, and to encourage young researchers to develop a vision on the future of their own field and neighbouring fields. Each DJA-member receives an annual traveling grant. Further, DJA organizes annual interdisciplinary two day conferences, open to invitees only, with lectures by 10 DJA-members. For further information (in Dutch) see http://www.knaw.nl/organisatie/dja.html.

• Jan Hogendijk receives award for book
   
  The World Prize for the Book of the Year of the Islamic Republic of Iran has selected the book "The Enterprise of Science in Islam: New Perspectives", J.P. Hogendijk, A.I. Sabra, eds., MIT Press, Cambridge Massachusetts, 2003, to be the best work in the field of Islamic studies within the European-American countries.

• Staff meeting and reception in honour of Bas Edixhoven's VICI-grant on Wednesday February 9
   
  The next staff and faculty meating will take place on February 9 from 4:00-5:00 pm in room 176. Afterwards there will be a reception at the FOO-bar (on the ground floor near to lecture room 313) on occasion of the recent award of a VICI-grant to Bas Edixhoven.

• General Colloquium lectures on Thursday February 10 in Delft and February 17 in Leiden
   
  This spring there will be a cooperation between the general mathematics colloquia of Delft and Leiden. The following people from Leiden (in alphabetical order) have agreed to give a lecture in Delft: Bas Edixhoven, Jan-Hendrik Evertse, Sara van de Geer, Marcel de Jeu, Sjoerd Verduyn-Lunel. The following people from Delft (in alphabetical order) have agreed to speak in Leiden: Roger Cooke, Klaas Pieter Hart, Arnold Heemink, Kees Oosterlee, Ben de Pagter. The first two lectures will be given by Sara van de Geer (in Delft) and Klaas Pieter Hart (in Leiden).

  February 10, 4:00-5:00 pm, Delft:
  Sara van de Geer: Adaptive learning
  

  February 17, 4:00-5:00, Leiden, Snellius room 174:
  Klaas Pieter Hart: Embeddability of the measure algebra

  For further information see http://www.math.leidenuniv.nl/~evertse/colloquium.shtml.

  Stieltjes Onderwijsweek: "Global and Variational Methods for ODEs and PDEs" from February 14-18 at Lorentz Center
   
  This workshop is meant for Master's students in their final year and Ph.D. students. Lectures are given by Jan Bouwe van den Berg, Felix Otto (presently Stieltjes Professor), Mark Peletier and Rob van der Vorst. The workshop is coordinated by Mark Peletier (TU Eindhoven). Further information.

• Intercity Number Theory Seminar on Friday February 18
   
  The Intercity Number Theory Seminar of February 18 is held in Leiden, with lectures by Capi Corrales, Clemens Fuchs, Robin de Jong and Eleonora Pellegrini. For further information see http://www.math.leidenuniv.nl/~desmit/ic.

• Inaugural lecture by Jan Hogendijk on Tuesday March 8 and seminar on March 8
   
  On March 8 Jan Hogendijk will give his inaugural lecture at Leiden University. Preceding his lecture there will be three other lectures on the theme "Mathematics across cultures" (Snellius, room 312).

  11:00-12:00:		Liesbeth de Wreede (Universiteit Utrecht): "Number is the measure of all": Snellius on the use of numbers in geometry
  12:00-  1:00:		Kim Plofker (Universiteit Utrecht and IIAS Leiden): Heron's formula and the geometry of quadrilaterals in Indian mathematics
  1:45-  2:45:		Karen Parshall (University of Virginia): The British Development of the Theory of Invariants (1841-1895)
  Jan Hogendijk's inaugural lecture will take place in the Academiegebouw, Rapenburg 73, Leiden.
  4:00-  5:00:		Jan Hogendijk's inaugural lecture: Geschenken uit het Oosten
  5:00:		Reception

  For more information on the program, take a look at: http://www.math.leidenuniv.nl/~jdaems/oratie.

• New full professors

  - Prof. Ronald Cramer in cryptology per June 1, 2004 (one day per week in Leiden, four days per week at CWI)

  I'd like to take this opportunity to introduce myself briefly to those colleagues I have not met so far. My name is Ronald Cramer, and as of June 1st 2004 I am Professor of Cryptology at the Mathematical Institute, with an appointment of one day per week. When not in Leiden, I lead the research group Cryptology and Information Security at CWI in Amsterdam, also since June 1st last year.
  My research is mainly concerned with mathematical cryptology, i.e., the mathematical techniques that are central to the design and analysis of methods for digital security, such as that provided by encryption or digital signatures.
  It's a great pleasure for me to be back in Holland after having worked abroad for 7½ years, at the ETH Zurich and the University of Aarhus. I am not a stranger to the Mathematical Institute, as I completed my undergraduate studies here in 1992, with specialization "algebra, number theory, geometry." After having completed my PhD research in cryptology at CWI at the end of 1996, I moved to ETH.
  Besides research and teaching my main professional activities include membership of the editorial board of Journal of Cryptology, the Board of Directors of the International Association of Cryptologic Research (IACR) and various program committees for international conferences. In March "De Jonge Akademie" of the KNAW will kick off, and I'm very much looking forward to my participation. My Cryptology course will start in the Fall.
  Presently Jan Hogendijk and I share the Kloosterman room 224A. I'm here mostly on Fridays or Thursdays. Don't hesitate to stop by, here or at CWI!

• New Ph.D. students

  - Christian Svensson per February 1, 2005 with Marcel de Jeu and Sergei Silvestrov (Lund)

• Guests of Peter Stevenhagen:

  - Eleonora Pellegrini (Pisa): During the next spring she will visit the number theory group. She is presently a Ph.D. student of Roberto Dvornicich. On February 18 she will give a lecture at the Intercity Number Theory seminar. group to work on her Ph.D. thesis with Bart de Smit.
  - Capi Corrales (Madrid): As part of a sabbatical she will visit our institute during the next spring, starting February 12. On February 18 she will give a lecture at the Intercity Number Theory Seminar.

• Guest of Rob Tijdeman:

  - Jaroslav Hancl (Ostrava): From February 8 to March 2 he will visit our institute and work with Rob Tijdeman in the framework of the Socrates/Erasmus agreement.

Visits/lectures outside our institute

- Peter Stevenhagen: On February 16 he will give an evening lecture on the "Ouderdagen 2005" (Parents' Days 2005) titled "Getaltheorie en Bankgeheim."

- Bart de Smit and Hendrik Lenstra: They will both give a lecture "Escher en het Droste-effect." Bart will speak on February 16 at the Geulincx College, Faculty Club Leiden, and Hendrik on February 25 at the Natuurkundig Gezelschap te Middelburg.

- Marcel de Jeu and Christian Svensson: From February 14-18 they will visit the University of Lund to cooperate with Sergei Sivestrov and Jun Tomiyama.

- Bert Peletier: From February 25-March 5 he will be in Cambridge, Massachusetts, where he will visit among others Boston University. There he will give a lecture on February 28.

Technical reports

MI 2005-01		M.V.S. Frasson: Symbolic computation of spectral projections and its application to neutral delay systems
MI 2005-02		F. Spieksma: Ave, Lyapunov functions!
MI 2005-03		C.J. van Duin. L.A. Peletier, I.S. Pop: A new class of entropy solutions of the Buckley-Leverett equation