Date and place of birth: May 13, 1958, Rotterdam (Netherlands)
Present citizenship: Dutch
Citizenship at birth: Dutch
Family status: Unmarried
Postbus 9512, 2300 RA Leiden
Present position: Universitair docent (assistant professor)
|Graduation:||September 28, 1979 (Universiteit Leiden)|
|Defense Ph-D. thesis:||September 7, 1983 (Universiteit Leiden)
Supervisor: Prof. dr. R. Tijdeman
|Research area:||Number theory.
In particular Diophantine approximations, finiteness problems for the number of solutions of Diophantine equations and Diophantine inequalities, and estimates for the number of solutions.
|Editorial work:||Editor of Compositio Mathematica|
for longer periods
(all on invitation):
Courses to first and second year mathematics students:|
Linear algebra, Algebra (rings), Algebra (fields and Galois theory)
Courses to third and higher years mathematics students: Basic number theory, Combinatorics, Cryptography, Computational number theory, Algebraic number theory, Diophantine approximation, Analytic number theory
Courses to non-mathematical students:
|Organization and administration:||- Member of the program committee of Eurocrypt 1987 (Amsterdam)
- Member of the organization committees of the Dutch Mathematical Conferences 1994, 2006, 2007.
- Writer (together with Jaap van de Griend) of the "zelfstudie t.b.v. de visitatiecommissie onderwijs wiskunde 1996" (report for a Dutch committee investigating the quality of the mathematics curricula at the various Dutch universities)
- Organizer of the workshop "Diophantine approximation" and the symposium in honour of the 60th birthday of Prof. Robert Tijdeman in 2003 (together with Frits Beukers and Pieter Moree)
- Organizer of the instructional conference "Solvability of Diophantine equations" and the workshop "Solvability of Diophantine equations" in 2007 (together with Mike Bennett, Frits Beukers and Rob Tijdeman)
- Organizer of the symposium "Number Theory and Discrete Mathematics" in honour of the 65th birthday of Prof. Robert Tijdeman in 2008 (together with Fred Bakker, Joost Batenburg and Lodewijk Kallenberg)
- Organizer of the General mathematics colloquium in Leiden 1996-2009 (together with Floske Spieksma and Frank Redig)
- Assistant education coordinator for mathematics 2010 -- (class schedules and study guide)
|Research experience:||From 1979-1983 I worked as a Ph-D student in Leiden, under
supervision of Rob Tijdeman and Frits Beukers. The purpose of my
Ph-D research was to give as good as possible estimates for the number
of solutions of Diophantine equations, using techniques from
From 1984-1988 I worked as a researcher at the CWI in Amsterdam in the cryptography group of David Chaum. There, my research was focused on cryptographic protocols and on the Data Encryption Standard.
In 1988 I went back to Leiden and continued the research I started as a Ph-D student. From 1988-1993 I was a KNAW fellow, and since 1993 a Universitair Docent in the Leiden number theory group. Since then I have been working on Diophantine approximation, Diophantine equations and Diophantine inequalities, in particular on matters such as the Thue-Mahler equation, discriminants and resultants of binary forms, decomposable form equations, S-unit equations, Faltings' Product Theorem, Schmidt's Subspace Theorem, symmetric improvements of Liouville's inequality, approximation of algebraic numbers by algebraic numbers of bounded degree.
My research in the past few years concerns generalizations and refinements of Schmidt's Subspace Theorem, estimating the number of equivalence classes of pairs of binary forms with given resultant, approximation of complex algebraic numbers by algebraic numbers of bounded degree, complexity of expansions of real algebraic numbers with respect to a given base, multiply monogenic orders, effective finiteness results for points from the intersection of a subvariety of a linear torus and a group of finite rank over the algebraic closure of Q, effective results on unit equations over finitely generated domains. I have recently finished a book with Kálmán Györy on unit equations. Kálmán and I are presently working on a second book on Diophantine problems related to discriminants of polynomials and binary forms.
|Lectures:||List of lectures|
Papers on number theory:|
A. Bérczes, B. Brindza, Y. Bugeaud, C. Pontreau, R.G. Ferretti, I. Gaál, K. Györy, N. Hirata-Kohno, P.Moree, H.P. Schlickewei, W.M. Schmidt, T.N. Shorey, J.H. Silverman, C.L. Stewart, R. Tijdeman, U. Zannier
Papers on cryptography: