**Diophantine Approximation**

July
28 – August 2, 2003

Diophantine Approximation is the branch of number theory dealing
with problems such as whether certain given numbers are rational or irrational,
or algebraic or transcendental, and how well given numbers can be approximated
by rational or algebraic numbers. The field has many applications, for instance
to Diophantine equations or Diophantine geometry. The purpose of the workshop
was to discuss new developments in Diophantine approximation and its
applications. There were about 50 registered participants all over the world,
which had been invited by the coordinators. On July 30 there was a special
symposium for a general audience in honor of Professor Robert Tijdeman.

During the workshop there were lectures in the morning
and in the late afternoon, with large breaks in between. Thursday afternoon and
Saturday afternoon were free. Most of the lectures were half hour reports on
new work. In addition there were some survey lectures of 45 minutes. In the
lectures, a very broad range of Diophantine approximation was covered:
irrationality and transcendence problems, approximation of real numbers by
algebraic numbers, applications to Diophantine equations, elliptic curves and
Diophantine geometry, connections with Nevanlinna theory, transcendence results
for Drin’feld modules, and computational aspects of Diophantine approximation.

The meeting was a succesfull one. The level of the lectures was
good to excellent, a large area of the subject was covered, and there was ample
time for informal contacts and discussions. Beginning next year there will be a
special issue of Acta Arithmetica in honor of Rob Tijdeman. In this issue a number
of papers presented during the conference will appear.

Another important factor in the success was the congenial
atmosphere of the Lorentz Center with its offices and meeting places. The
friendly cooperation and the efforts of its staff made the workshop into a
smooth operation. We would like to thank them heartily for it.

**F.** **Beukers **(University
Utrecht, The Netherlands)

**J-H.** **Evertse** (Leiden University, The Netherlands)

**P.** **Moree** (University Amsterdam, The Netherlands)