Fourth International Conference on Computability and Complexity in Analysis

June 16-18, 2007, Siena, Italy

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The conference is concerned with the theory of computability and complexity over real-valued data.

Computability and complexity theory are two central areas of research in mathematical logic and theoretical computer science. Computability theory is the study of the limitations and abilities of computers in principle. Computational complexity theory provides a framework for understanding the cost of solving computational problems, as measured by the requirement for resources such as time and space. The classical approach in these areas is to consider algorithms as operating on finite strings of symbols from a finite alphabet. Such strings may represent various discrete objects such as integers or algebraic expressions, but cannot represent general real or complex numbers, unless they are rounded.

Most mathematical models in physics and engineering, however, are based on the real number concept. Thus, a computability theory and a complexity theory over the real numbers and over more general continuous data structures is needed. Unlike the well established classical theory over discrete structures, the theory of computation over continuous data is still in early stages of development, despite remarkable progress in recent years. Many important fundamental problems have not yet been studied, and presumably numerous unexpected and surprising results are waiting to be detected.

Scientists working in the area of computation on real-valued data come from different fields, such as theoretical computer science, domain theory, logic, constructive mathematics, computer arithmetic, numerical mathematics and all branches of analysis. The conference provides a unique opportunity for people from such diverse areas to meet, present work in progress and exchange ideas and knowledge.

The topics of interest include foundational work on various models and approaches for describing computability and complexity over the real numbers. They also include complexity-theoretic investigations, both foundational and with respect to concrete problems, and new implementations of exact real arithmetic, as well as further developments of already existing software packages. We hope to gain new insights into computability-theoretic aspects of various computational questions from physics and from other fields involving computations over the real numbers.

This year CCA 2007 is co-located with the conference CiE 2007, Computability in Europe 2007: Computation and Logic in the Real World, University of Siena, June 18-23, 2007.

Scientific Program Committee

Organizing Committee

Programme & Venue

The tentative programme of the conference is available here:

CCA 2007 Program

The venue for the CCA 2007 talks is the College Santa Chiara (Auditorium). Here you can find a map and instructions how to find the the CCA 2007 from Florence airport.

Group Picture

Some participants of CCA 2007


For information on registration and fees, please go to the following page:

CCA & CiE Registration.


Accommodation can be booked via the CiE 2007 web page:


For CCA 2007 participants eight rooms at the Santa Chiara will be available until June 18, 3 nights starting from June, 15.


Authors are invited to submit a PostScript or PDF version of a paper to



Accepted papers will be published as CCA 2007 proceedings in Electronic Notes in Theoretical Computer Science (ENTCS). In addition, a printed version (as a technical report) will be available at the conference.
It is planned to publish a special issue of the journal Mathematical Logic Quarterly dedicated to CCA 2007 after the conference.


Submission deadline: April 8, 2007
Notification of authors: May 7, 2007
Final Version: May 27, 2007

CCA Steering Committee

Vasco Brattka (Cape Town, South Africa), Peter Hertling (Neubiberg, Germany), Ker-I Ko (Stony Brook, USA), Klaus Weihrauch, chair (Hagen, Germany), Ning Zhong (Cincinnati, USA)

Further Information

For further information, please contact