Intercity Number Theory Seminar
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2002

February 8, Leiden (UL), Room 174.

10:30-11:30  J. Hancl, Irrationality and transcendence of series of rational numbers
11:45-12:45 Jan-Hendrik Evertse, Multivariate Diophantine equations with many solutions

The building will close at 13:00 because of the "Dies". At 15:00 an honorary doctorate will be given to H. Brezis in the Pieterskerk in Leiden

March 8, Utrecht, Room K11
13:00-14:45  Gunther Cornelissen, Diophantine sets and abelian varieties.
15:00-16:45 Frits Beukers, Factorisation on a quantum computer

March 22, Groningen, Room RC 59

11:45 - 12:30   Jaap Top,Introduction to Drinfeld modules
13:15 - 15:00   Gert-Jan van der Heiden, A local-global problem for elliptic curves and Drinfeld modules
15:15 - 17:00   Lenny Taelman, Moduli of Drinfeld modules

April 4, Eindhoven

At the first of the two days of the Nederlands Mathematisch Congres the bi-annual Beeger lecture will be given by Bjorn Poonen. In the afternoon there will be a number theory session "Minisymposium getaltheorie" organised by Peter Stevenhagen and Rob Tijdeman.
11:45-12:45  Bjorn Poonen Beeger lecture
13:45-14:15 Bart de Smit
14:20-14:50 Pieter Moree
14:55-15:25 Johnny Edwards

April 26, VU Amsterdam, Room N343 (route)
11:00-12:00 Lenny Taelman, Lie symmetries and Galois groups of linear differential equations
12:15-12:45 &
13:30-14:00
Jaap Top, Introduction to (generalized) symmetries of evolution equations
14:15-15:15 Peter van der Kamp Classifying integrable systems using number theory

May 17, Eindhoven (TUE, route), HG 6.09
11:30-12:15 Andries Brouwer, Introduction to Lie algebras
Abstract: Definition of Lie algebras and root systems, and the classification of split (semi-)simple Lie algebras in characteristic 0.
13:15-14:00 Willem de Graaf, Constructing homomorphisms between Verma modules
Abstract: Fix a Borel subalgebra b of a simple Lie algebra g. Then g-modules induced from irreducible b-modules are called Verma modules of g. The space of homomorphisms between two Verma modules (w.r.t. the same b) is at most one-dimensional, and any such homomorphism which is non-zero is in fact injective. Hence, there is a natural notion of inclusion among Verma modules. This talk describes how to implement Verma modules in GAP, and how to compute explicitly the non-zero homomorphisms among them.
14:15-15:00 Don Taylor, Computations in semisimple algebraic groups
Abstract: Semisimple algebraic groups are closely related to semisimple Lie algebras. In particular, the root systems classifying the latter give rise to a normal form of elements of the former: the so-called Steinberg presentation. This raises various computational questions, such as: how to find the Steinberg presentation of an element of a semisimple algebraic group, which is given by its matrix in some representation of that group?
15:15-16:00 Jan Draisma, The adjoint representation of certain Lie algebras of polynomial vector fields
Abstract: The action of a complex simple algebraic group G on a homogeneous space G/P where P is a parabolic subgroup with Abelian unipotent radical gives rise to an action of the Lie algebra g of G by vector fields on some open dense part U of G/P. The Lie algebra D of all vector fields on U can thus be viewed as a g-module, the action being given by the commutator. As such, D turns out to have a beatiful structure; for example, its composition factors seem to be parameterized by certain double cosets in the Weyl group of g.

May 31, Leiden, Room 174
11:30-12:15 Tom Schmidt, Galois orbits of congruence curves defined by nonarithmetic groups
12:30-13:15 Robert Carls, Counting points by a method of Mestre
14:15-15:00 Stefania Cavallar, On the Three-Large-Primes Variant of the Number Field Sieve
15:15-16:00 Christiaan van de Woestijne, Quadratic Forms over Finite Fields
16:15-17:00 Reinier Bröker, The Hopf-algebroid of formal grouplaws

Fall 2002

September 13 Mathematisch Instituut Leiden, Room 412
11:00-11:45,
12:00-12:45
Hendrik Lenstra, Primality testing in polynomial time
after Agrawal, Kayal and Saxena [PDF].
13:45-14:30 Rob Tijdeman, Catalan's conjecture. An introduction
after Mihailescu; see Bilu's paper [ PS, PDF])
14:45-15:30 Pingzhi Yuan, Simultaneous quadratic equations
15:45-16:45 Ronald van Luijk, Elliptic curves with large rank over function fields
after Douglas Ulmer [Mathematics ArXiv]
September 27 Lorentz Center Leiden, room N201 in the Huygens building.
This meeting is part of EANT.
10.15-11.15 Rene Schoof, Applications of class field theory
11.45-12.45 Capi Corrales, The support problem
14.00-15.00 Bas Edixhoven, Complex multiplication and Galois action
15.30-16.30 Juergen Klueners, Constructive Galois theory
October 11 Groningen, room RC150
11:30-12:30 Alf van der Poorten, Quadratic number fields with small regulator
13:30-14:30 Rob Tijdeman, Introduction to Catalan's conjecture, part II
see Bilu's paper [ PS, PDF]) on Mihailescu's proof
14:45-15:45 Remke Kloosterman, Extremal elliptic surfaces
16:00-17:00 Jaap Top, Character sums and K3's with Picard number 19
October 18 CWI, first three talks in room M280, last talk in Z011.
11:00-11:50 Alf van der Poorten, Some questions suitable for the Monthly
12:10-13:00 Joost Batenburg, Discrete tomography
14:00-15:00 Szabolcs Tengely, The Runge-type diophantine argument in Mihailescu's proof
15:30-16:00 Hendrik Lenstra, Escher en het Droste-effect
November 1 Utrecht. The morning talks take place in room 611 of the Mathematical Institute.
The afternoon lecture, which is due to the hospitality of the automorphic forms seminar will be at the Buys-Ballot Lab, room 105b.
11:15-12:00 Reinier Bröker, Stickelberger's theorem and Catalan's conjecture
12:15-13:00 Bas Jansen, Thaine's theorem on annihilating class-groups
14:15-16:00 Don Zagier, Traces of singular moduli
November 22 Nijmegen; parallel with Najaarssymposium WG
The WG-talks (te Riele, Bosma, Forum) take place in N0016 (CZ N1), the others in N0011 (CZ N5).
11:00-11:45 Herman te Riele, Toegepaste getaltheorie: de alomtegenwoordigheid van de priemgetallen
12:00-12:30 H.W. Lenstra, x2 = yn+1
13:30-14:15 Wieb Bosma, Computer Algebra toegepast
14:30-15:15 Szabolcs Tengely, On Cassels' relations
15:15-16:00 Bas Edixhoven, Equations for covers of P1
16:15-17:00 Forum, "Wiskunde studie de breedte in?"
December 6 Leiden, room 412.
12:00-13:00 Adriaan Herremans, Arithmetic with modular symbols
14:00-14:30 Reinier Bröker, Mihailescu's theorem on Wieferich pairs
14:45-15:45
16:00-17:00
H.W. Lenstra, Mihailescu's proof of Catalan's conjecture