The Mathematical Institute Newsletter is maintained by Jan-Hendrik Evertse. The newsletter will be 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 December newsletter, such as announcements, personal notes, visits to conferences, guests, lectures of general interest, Ph.D.-defenses, etc. should be sent by e-mail to evertse at math.leidenuniv.nl before November 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
 

• Compositio Afternoon on Friday November 7
   
  As of January 1, 2004 Compositio Mathematica will be published by the London Mathematical Society and Cambridge University Press on behalf of the Foundation Compositio Mathematica. This joyful event will be celebrated with two lectures on November 7 and a reception at the Korteweg-de Vries Instituut in Amsterdam. Those interested are cordially invited. For further information please contact Gerard van der Geer ( geer at science.uva.nl)
  The program for the afternoon of November 7, 2003 is: (see also http://www.science.uva.nl/~geer/compositiodag.html)
   
  

  3:00 pm		C. Deninger: Elliptic curves over finite fields and transversal index theory
  4:15 pm		V. Remmert: The Founding Years of Compositio Mathematica: 'Ce périodique foncièrement international'
  5:00 pm		Reception offered by the London Mathematical Society and Cambridge University Press

• Lecture by Prof. Dmitry Logachev (Universidad Simon Bolivar, Venezuela) on Monday November 10
   
  Professor Dmitry Logachev (guest of Bas Edixhoven, see below) will give a lecture at the geometry seminar on Monday November 10. For further information see the website of the geometry seminar, http://www.math.leidenuniv.nl/~gabor/geom_sem.html
  Title: Action of Hecke correspondences on subvarieties of Shimura varieties
  Time/place: 4:00-5:00 pm, room 402.

• Ph.D. defense by Richard Groenewegen on Tuesday November 18
   
  On November 18 at 2:15 pm Richard Groenewegen will defend his Ph.D. thesis, titled Vector bundles and geometry of numbers.
  His supervisor is Prof. Hendrik Lenstra and his co-supervisor Dr. Bart de Smit. The ceremony is at the usual place (Senaatskamer, Academiegebouw, Rapenburg 73).

• Talk by ing. Theun de Vreede (Haagse Hogeschool) on Thursday November 20
   
  Theun de Vreede will give a talk at the students seminar about his graduation project. He has graduated under supervision of Bart de Smit on an interactive extension of the 'Escher project'. The audience will be Eschered during the talk (which will be in Dutch).
  Title: Escher, live!
  Time/place: 16:00 in room 174 or 412.

• KWG-Kaleidoskoopdag on Thursday November 27
   
  Every year, there is a 'Kaleidoskoopdag' at one of the Dutch universities, under the auspices of the Koninklijk Wiskundig Genootschap (Royal Dutch Mathematical Society), with lectures (in Dutch) for undergraduate mathematics students. The Kaleidoskoopdag of 2003 takes place in Leiden, and it is organized by the student union 'De Leidsche Flesch.' The subject is Cryptography. Speakers include Peter Stevenhagen and Henk van Tilborg (Technical University of Eindhoven).

• Christmas buffet dinner on Thursday December 18
   
  The annual Christmas buffet dinner of 2003 will take place on December 18. Further details will follow.

• Wall screen contest
   
  On each floor of our building, the walls of the corridors have been provided with new screens, showing all sorts of illustrations. Each floor (the I-group on the ground floor, the computer science department on the first floor and the mathematics department on the second floor) had to design its own wall screens, in the frame of a contest organized by the real estate office of our university. This contest has been won by the mathematics department team, consisting of Aldine Aaten, Sophie Raynor, Fred Bakker, Peter Stevenhagen, Sara van de Geer, Sander Hille, Franz Merkl and Bart de Smit.
  The awarded prize is, that the walls on both sides of the door on the west side of the canteen will be filled up with epoch-making mathematical art. The design of this will be supervised by Hendrik Lenstra and Bart de Smit. Bart de Smit will collect all concrete suggestions.

Personal notes
 

• New employees (Ph-D students):
   
  

  - drs. Bernadetta Tarigan per September 1, 2003 (Prof.dr. Sara van de Geer, NWO)

  Bernadetta Tarigan will work in the project entitled "Classification and Adaptation"

• New employees (student assistants for education from September 1, 2003- January 1, 2004):

  - P. Bruin

  - mrs. S. Raynor

  - M. van der Schans

  - A. Stolk

  - A. Veldman

  - E. de Vries

• New employees (student assistants for public relations per September 1, 2003):

  - E. Jongsma

  - F.D. Werkhoven

• New employees (computer support):

  - drs. F.J.E. Bemmelen (helpdesk) per August 1, 2003

  - K.F.D. Rietveld (systems management) per August 1, 2003

• New employees (other):

  - Dr. B. Hanzon

  Dr. Bernard Hanzon is a visiting collaborator in the group of Sjoerd Verduyn Lunel. His speciality is mathematical systems theory with applications in financial econometry.

Guests
 

• Guests of P. Stevenhagen:

  - Tommy Bülow (University of Copenhagen) from September-November.

• Guest of H.W. Lenstra and P. Stevenhagen:

  - Jan Bouw (Teacher in Research/Leraar in Onderzoek). He will visit our institute on Fridays.

• Guest of B. Edixhoven:

  -Prof. Dmitry Logachev (Universidad Simon Bolivar, Venezuela). He will visit our institute on November 10-12.

Visits/lectures outside our institute

- Peter Stevenhagen: On November 10 he will give a colloquium lecture at the IU Bremen (How to construct your personal elliptic curve), On November 20 he will give a 'Basic Notions in Mathematics'-talk in the Mathematics colloquium in Utrecht, titled: Algebraic Numbers. On November 27 he will give a lecture at the 'WG-kaleidoskoopdag' on cryptography organized by the student union 'De Leidsche Flesch'.
- Bert Peletier: From November 3-15 he will visit the Rutgers University at New Brunswick (New Jersey, USA).

Technical reports

MI 2003-15

F. Merkl and S.W.W. Rolles: Edge-reinforced random walk on a ladder.