**16-18 June 2007
Siena, Italy**

Call for Papers CCA 2007 Fourth International Conference on COMPUTABILITY AND COMPLEXITY IN ANALYSIS June 16-18, 2007, Siena, Italy http://cca-net.de/cca2007/ Authors are invited to submit a PostScript or PDF version of a paper to <cca-submission@FernUni-Hagen.de> Submission deadline: March 15, 2007 Notification of authors: April 15, 2007 Final versions: May 5, 2007 Conference: June 16-18, 2007 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. http://www.amsta.leeds.ac.uk/~pmt6sbc/cie07.html SCOPE of CCA 2007 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.