The aim of the symposia on "Real Numbers and Computers" is to bring together specialists from various research areas, all concerned with problems related to computations based on real numbers. These computations may use any number system implemented by a software package or in hardware, including floating and fixed point, "serial", "on line", continued fractions, "exact", multiple precision, interval and stochastic arithmetic. Results are sought on both applied and fundamental questions. Important topics discussed during these conferences include but are not limited to:
  • Foundation and properties of number systems
  • Computability and complexity
  • Formal aspects and automatic proof checking
  • Links with number theory and automata theory
  • Basic arithmetic operations
  • Implementation of the standard and special functions
  • Engineering of floating and fixed point algorithms
  • Symbolic manipulation of numbers
  • Accuracy and reliability for applications and industry
  • Robust geometric algorithms and exact geometric computation
  • Hardware design support and implementations
The conference will feature invited lectures and contributed talks.

Invited Lectures

Benno Fuchssteiner, Paderborn, Germany
Simon Plouffe, Montreal, Canada
Stefan Schirra, Magdeburg, Germany


Registration deadline: October 24, 2004


Program Committee

Jean-Paul Allouche, Orsay, France
Jean-Claude Bajard, Montpellier, France
Vasco Brattka, Cape Town, South Africa
Jean-Marie Chesneaux, Paris, France
Marc Daumas, Lyon, France
Martín Escardó, Birmingham, United Kingdom
Guy Even, Tel Aviv, Israel
Christiane Frougny, Paris, France (Chair)
Peter Kornerup, Odense, Denmark
Philippe Langlois, Perpignan, France
Dominique Michelucci, Dijon, France
Paolo Montuschi, Torino, Italy
Michael Parks, Sun, United States
Siegfried Rump, Hamburg, Germany
Laurent Thery, Sophia Antipolis, France

Steering Committee

Jean-Claude Bajard, Montpellier, France
Jean-Marie Chesneaux, Paris, France
Marc Daumas, Lyon, France
Christiane Frougny, Paris, France
Peter Kornerup, Odense, Denmark (Chair)
Dominique Michelucci, Dijon, France
Jean-Michel Muller, Lyon, France

Organizing Committee

Vasco Brattka, Cape Town, South Africa (Publicity Chair)
Norbert Müller, Trier, Germany (Local Organizer)

Contributed Talks

  • Generating formally certified bounds on values and round-off errors
    Marc Daumas & Guillaume Melquiond

  • A proven correctly rounded logarithm in double-precision
    de Dinechin, Loirat, Muller

  • On intermediate precision required for correctly-rounding decimal-to-binary floating-point conversion
    M. Hack

  • An extension of Chaitin's halting probability Omega to measurement operator in infinite dimensional quantum system
    K. Tadaki

  • Bridging the gap between formal specification and bit-level floating-point arithmetic
    S. Boldo

  • A fast algorithm for Julia sets of hyperbolic rational functions
    Robert Rettinger

  • On the hierarchy of Delta_02-numbers
    Xizhong Zheng

  • Automata, Borel functions and real numbers in Pisot basis
    Cagnard, Simonnet

  • A comparison of real and complex pseudozero sets for polynomials with real coefficients
    Graillat, Langlois

  • Software division and square root using Goldschmidt's algorithm
    Peter Markstein

  • A comparison of polynomial evaluation schemes
    L. Fousse, S. Schmitt

  • The generic multiple-precision floating-point addition with exact rounding (as in the MPFR library)
    Vincent Lefevre

There will also be an informal session open to present work in progress. Potential speakers might contact Christiane Frougny (Christiane.Frougny@liafa.jussieu.fr) with an intended title for such a presentation. Here you can find the preliminary
of the conference.
This is a picture of some conference participants.

Special Issue

A special issue on Real Numbers and Computers of the journal

Theoretical Informatics and Applications

is to follow the conference. Authors of the conference will be strongly encouraged to propose expanded work for review and inclusion. Here is the current

Call for Papers.

Registration & Accomodation

Participants are invited to register for the conference until

November 7, 2004

by sending the following fax form to Norbert Müller: Registration Form. The conference fee is 120 Euro. Accomodation is offered by the Dagstuhl Center for 80 Euros per day (including all meals). There are only a few possibilities of staying until Thursday, on a first-come-first-serve basis. This also applies to double rooms.


The conference takes place in the International Conference and Research Center for Computer Science Schloß Dagstuhl in Wadern, Germany from November 15-17, 2004. On the webpage of the center, further information on travelling and information for guests are available.
The closing of the conference will be on Wednesday at noon and the lunch will end at about 1 p.m..

© 2003-2004 Vasco Brattka